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William Burroughs and I first went into techniques of writing, together, back in room No. 15 of the Beat Hotel during the cold Paris spring of 1958... Burroughs was more intent on Scotch-taping his photos together into one great continuum on the wall, where scenes faded and slipped into one another, than occupied with editing the monster manuscript... "Naked Lunch" appeared and Burroughs disappeared. He kicked his habit with Apomorphine and flew off to London to see Dr Dent, who had first turned him on to the cure. While cutting a mount for a drawing in room No. 15, I sliced through a pile of newspapers with my Stanley blade and thought of what I had said to Burroughs some six months earlier about the necessity for turning painters' techniques directly into writing. I picked up the raw words and began to piece together texts that later appeared as "First Cut-Ups" in "Minutes to Go" (Two Cities, Paris 1960). When Burroughs returned from London in September 1959, Gysin not only shared his discovery with his friend but the new techniques he had developed for it. Burroughs then put the techniques to use while completing "Naked Lunch" and the experiment dramatically changed the landscape of American literature. Gysin helped Burroughs with the editing of several of his novels including "Interzone", and wrote a script for a film version of "Naked Lunch", which was never produced. The pair collaborated on a large manuscript for Grove Press titled "The Third Mind", but it was determined that it would be impractical to publish it as originally envisioned. The book later published under that title incorporates little of this material. Interviewed for "The Guardian" in 1997, Burroughs explained that Gysin was "the only man that I've ever respected in my life. I've admired people, I've liked them, but he's the only man I've ever respected." In 1969, Gysin completed his finest novel, "The Process", a work judged by critic Robert Palmer as "a classic of 20th century modernism".
A consummate innovator, Gysin altered the cut-up technique to produce what he called permutation poems in which a single phrase was repeated several times with the words rearranged in a different order with each reiteration. An example of this is "I don't dig work, man / Man, work I don't dig." Many of these permutations were derived using a random sequence generator in an early computer program written by Ian Sommerville. Commissioned by the BBC in 1960 to produce material for broadcast, Gysin's results included "Pistol Poem", which was created by recording a gun firing at different distances and then splicing the sounds. That year, the piece was subsequently used as a theme for the Paris performance of Le Domaine Poetique, a showcase for experimental works by people like Gysin, François Dufrêne, Bernard Heidsieck, and Henri Chopin. With Sommerville, he built the Dreamachine in 1961. Described as "the first art object to be seen with the eyes closed", the flicker device uses alpha waves in the 8–16 Hz range to produce a change of consciousness in receptive viewers.
Later years. In April 1974, while sitting at a social engagement, Gysin had a very noticeable rectal bleeding. In May he wrote to Burroughs complaining he was not feeling well. A short time later he was diagnosed with colon cancer and began to receive cobalt treatment. Between December 1974 and April 1975, Gysin had to undergo several surgeries, among them a very traumatic colostomy, that drove him to extreme depression and to a suicide attempt. Later, in "Fire: Words by Day – Images by Night" (1975), a crudely lucid text, he would describe the horrendous ordeal he went through. In 1985 Gysin was made an American Commander of the French Ordre des Arts et des Lettres. He'd begun to work extensively with noted jazz soprano saxophonist Steve Lacy. They recorded an album in 1986 with French musician Ramuntcho Matta, featuring Gysin singing/rapping his own texts, with performances by Lacy, Don Cherry, Elli Medeiros, Lizzy Mercier Descloux and more. The album was reissued on CD in 1993 by Crammed Discs, under the title "Self-Portrait Jumping".
Death. On 13 July 1986 Brion Gysin died of lung cancer. Anne Cumming arranged his funeral and for his ashes to be scattered at the Caves of Hercules in Morocco. An obituary by Robert Palmer published in "The New York Times" described him as a man who "threw off the sort of ideas that ordinary artists would parlay into a lifetime career, great clumps of ideas, as casually as a locomotive throws off sparks". Later that year a heavily edited version of his novel, "The Last Museum", was published posthumously by Faber & Faber (London) and by Grove Press (New York). As a joke, Gysin had contributed a recipe for marijuana fudge to a cookbook by Alice B. Toklas; it was included for publication, becoming famous under the name Alice B. Toklas brownies. Burroughs on the Gysin cut-up. In a 1966 interview by Conrad Knickerbocker for "The Paris Review", William S. Burroughs explained that Brion Gysin was, to his knowledge, "the first to create cut-ups": A friend, Brion Gysin, an American poet and painter, who has lived in Europe for thirty years, was, as far as I know, the first to create cut-ups. His cut-up poem, "Minutes to Go", was broadcast by the BBC and later published in a pamphlet. I was in Paris in the summer of 1960; this was after the publication there of "Naked Lunch". I became interested in the possibilities of this technique, and I began experimenting myself. Of course, when you think of it, "The Waste Land" was the first great cut-up collage, and Tristan Tzara had done a bit along the same lines. Dos Passos used the same idea in 'The Camera Eye' sequences in "USA". I felt I had been working toward the same goal; thus it was a major revelation to me when I actually saw it being done.
Influence. According to José Férez Kuri, author of "Brion Gysin: Tuning in to the Multimedia Age" (2003) and co-curator of a major retrospective of the artist's work at The Edmonton Art Gallery in 1998, Gysin's wide range of "radical ideas would become a source of inspiration for artists of the Beat Generation, as well as for their successors (among them David Bowie, Mick Jagger, Keith Haring, and Laurie Anderson)". Other artists include Genesis P-Orridge, John Zorn (as displayed on the 2013's Dreamachines album) and Brian Jones. Selected bibliography. Gysin is the subject of John Geiger's biography, "Nothing Is True Everything Is Permitted: The Life of Brion Gysin", and features in "Chapel of Extreme Experience: A Short History of Stroboscopic Light and the Dream Machine", also by Geiger. "Man From Nowhere: Storming the Citadels of Enlightenment with William Burroughs and Brion Gysin", a biographical study of Burroughs and Gysin with a collection of homages to Gysin, was authored by Joe Ambrose, Frank Rynne, and Terry Wilson with contributions by Marianne Faithfull, John Cale, William S. Burroughs, John Giorno, Stanley Booth, Bill Laswell, Mohamed Hamri, Keith Haring and Paul Bowles. A monograph on Gysin was published in 2003 by Thames and Hudson. Works. Prose Radio Cinema Music Painting
Bulgarian Bulgarian may refer to:
BCG vaccine The Bacillus Calmette–Guérin (BCG) vaccine is a vaccine primarily used against tuberculosis (TB). It is named after its inventors Albert Calmette and Camille Guérin. In countries where tuberculosis or leprosy is common, one dose is recommended in healthy babies as soon after birth as possible. In areas where tuberculosis is not common, only children at high risk are typically immunized, while suspected cases of tuberculosis are individually tested for and treated. Adults who do not have tuberculosis and have not been previously immunized, but are frequently exposed, may be immunized, as well. BCG also has some effectiveness against Buruli ulcer infection and other nontuberculous mycobacterial infections. Additionally, it is sometimes used as part of the treatment of bladder cancer. Rates of protection against tuberculosis infection vary widely and protection lasts up to 20 years. Among children, it prevents about 20% from getting infected and among those who do get infected, it protects half from developing disease. The vaccine is injected into the skin. No evidence shows that additional doses are beneficial.
Serious side effects are rare. Redness, swelling, and mild pain often occur at the injection site. A small ulcer may also form with some scarring after healing. Side effects are more common and potentially more severe in those with immunosuppression. Although no harmful effects on the fetus have been observed, there is insufficient evidence about the safety of BCG vaccination during pregnancy. Therefore, the vaccine is not recommended for use during pregnancy. The vaccine was originally developed from "Mycobacterium bovis", which is commonly found in cattle. While it has been weakened, it is still live. The BCG vaccine was first used medically in 1921. It is on the World Health Organization's List of Essential Medicines. , the vaccine is given to about 100 million children per year globally. However, it is not commonly administered in the United States. Medical uses. Tuberculosis. The main use of BCG is for vaccination against tuberculosis. BCG vaccine can be administered after birth intradermally. BCG vaccination can cause a false positive Mantoux test.
The most controversial aspect of BCG is the variable efficacy found in different clinical trials, which appears to depend on geography. Trials in the UK consistently show a 60 to 80% protective effect. Still, those trials conducted elsewhere have shown no protective effect, and efficacy appears to fall the closer one gets to the equator. A 1994 systematic review found that BCG reduces the risk of getting tuberculosis by about 50%. Differences in effectiveness depend on region, due to factors such as genetic differences in the populations, changes in environment, exposure to other bacterial infections, and conditions in the laboratory where the vaccine is grown, including genetic differences between the strains being cultured and the choice of growth medium. A systematic review and meta-analysis conducted in 2014 demonstrated that the BCG vaccine reduced infections by 19–27% and reduced progression to active tuberculosis by 71%. The studies included in this review were limited to those that used interferon gamma release assay.
The duration of protection of BCG is not clearly known. In those studies showing a protective effect, the data are inconsistent. The MRC study showed protection waned to 59% after 15 years and to zero after 20 years; however, a study looking at Native Americans immunized in the 1930s found evidence of protection even 60 years after immunization, with only slightly waning in efficacy. BCG seems to have its greatest effect in preventing miliary tuberculosis or tuberculosis meningitis, so it is still extensively used even in countries where efficacy against pulmonary tuberculosis is negligible. The 100th anniversary of the BCG vaccine was in 2021. It remains the only vaccine licensed against tuberculosis, which is an ongoing pandemic. Tuberculosis elimination is a goal of the World Health Organization (WHO). The development of new vaccines with greater efficacy against adult pulmonary tuberculosis may be needed to make substantial progress. Efficacy. Several possible reasons for the variable efficacy of BCG in different countries have been proposed. None has been proven, some have been disproved, and none can explain the lack of efficacy in low tuberculosis-burden countries (US) and high tuberculosis-burden countries (India). The reasons for variable efficacy have been discussed at length in a WHO document on BCG.
Mycobacteria. BCG has protective effects against some nontuberculosis mycobacteria. Cancer. BCG has been one of the most successful immunotherapies. BCG vaccine has been the "standard of care for patients with bladder cancer (NMIBC)" since 1977. By 2014, more than eight different considered biosimilar agents or strains used to treat nonmuscle-invasive bladder cancer. Method of administration. A pre-injection tuberculin skin test is usually carried out before administering the BCG vaccine. A reactive tuberculin skin test is a contraindication to BCG due to the risk of severe local inflammation and scarring; it does not indicate immunity. BCG is also contraindicated in certain people who have IL-12 receptor pathway defects. BCG is given as a single intradermal injection at the insertion of the deltoid. If BCG is accidentally given subcutaneously, then a local abscess may form (a "BCG-oma") that can sometimes ulcerate, and may require treatment with antibiotics immediately, otherwise without treatment it could spread the infection, causing severe damage to vital organs. An abscess is not always associated with incorrect administration, and it is one of the more common complications that can occur with the vaccination. Numerous medical studies on the treatment of these abscesses with antibiotics have been done with varying results, but the consensus is once pus is aspirated and analysed, provided no unusual bacilli are present, the abscess will generally heal on its own in a matter of weeks.
The characteristic raised scar that BCG immunization leaves is often used as proof of prior immunization. This scar must be distinguished from that of smallpox vaccination, which it may resemble. When given for bladder cancer, the vaccine is not injected through the skin but is instilled into the bladder through the urethra using a soft catheter. Adverse effects. BCG immunization generally causes some pain and scarring at the site of injection. The main adverse effects are keloids—large, raised scars. The insertion to the deltoid muscle is most frequently used because the local complication rate is smallest when that site is used. Nonetheless, the buttock is an alternative site of administration because it provides better cosmetic outcomes. BCG vaccine should be given intradermally. If given subcutaneously, it may induce local infection and spread to the regional lymph nodes, causing either suppurative (production of pus) or nonsuppurative lymphadenitis. Conservative management is usually adequate for nonsuppurative lymphadenitis. If suppuration occurs, it may need needle aspiration. For unresolved suppuration, surgical excision may be required. Evidence for the treatment of these complications is scarce.
Uncommonly, breast and gluteal abscesses can occur due to haematogenous (carried by the blood) and lymphangiomatous spread. Regional bone infection (BCG osteomyelitis or osteitis) and disseminated BCG infection are rare complications of BCG vaccination, but potentially life-threatening. Systemic antituberculous therapy may be helpful in severe complications. When BCG is used for bladder cancer, around 2.9% of treated patients discontinue immunotherapy due to a genitourinary or systemic BCG-related infection, however while symptomatic bladder BCG infection is frequent, the involvement of other organs is very uncommon. When systemic involvement occurs, liver and lungs are the first organs to be affected (1 week [median] after the last BCG instillation). If BCG is accidentally given to an immunocompromised patient (e.g., an infant with severe combined immune deficiency), it can cause disseminated or life-threatening infection. The documented incidence of this happening is less than one per million immunizations given. In 2007, the WHO stopped recommending BCG for infants with HIV, even if the risk of exposure to tuberculosis is high, because of the risk of disseminated BCG infection (which is roughly 400 per 100,000 in that higher risk context).
Usage. The person's age and the frequency with which BCG is given have always varied from country to country. The WHO recommends childhood BCG for all countries with a high incidence of tuberculosis and/or high leprosy burden. This is a partial list of historic and active BCG practices around the globe. A complete atlas of past and present practice has been generated. As of 2022, 155 countries offer the BCG vaccine in their schedule. Manufacture. BCG is prepared from a strain of the attenuated (virulence-reduced) live bovine tuberculosis bacillus, "Mycobacterium bovis", that has lost its ability to cause disease in humans. It is specially subcultured in a culture medium, usually Middlebrook 7H9. Because the living bacilli evolve to make the best use of available nutrients, they become less well-adapted to human blood and can no longer induce disease when introduced into a human host. Still, they are similar enough to their wild ancestors to provide some immunity against human tuberculosis. The BCG vaccine can be anywhere from 0 to 80% effective in preventing tuberculosis for 15 years; however, its protective effect appears to vary according to geography and the lab in which the vaccine strain was grown.
Several companies make BCG, sometimes using different genetic strains of the bacterium. This may result in different product characteristics. OncoTICE, used for bladder instillation for bladder cancer, was developed by Organon Laboratories (since acquired by Schering-Plough, and in turn acquired by Merck & Co.). A similar application is the product of Onko BCG of the Polish company Biomed-Lublin, which owns the Brazilian substrain M. bovis BCG Moreau which is less reactogenic than vaccines including other BCG strains. Pacis BCG, made from the Montréal (Institut Armand-Frappier) strain, was first marketed by Urocor in about 2002. Urocor was since acquired by Dianon Systems. Evans Vaccines (a subsidiary of PowderJect Pharmaceuticals). Statens Serum Institut in Denmark has marketed a BCG vaccine prepared using Danish strain 1331. The production of BCG Danish strain 1331 and its distribution was later undertaken by AJVaccines company since the ownership transfer of SSI's vaccine production business to AJ Vaccines Holding A/S which took place on 16 January 2017. Japan BCG Laboratory markets its vaccine, based on the Tokyo 172 substrain of Pasteur BCG, in 50 countries worldwide.
According to a UNICEF report published in December 2015, on BCG vaccine supply security, global demand increased in 2015 from 123 to 152.2 million doses. To improve security and to [diversify] sources of affordable and flexible supply," UNICEF awarded seven new manufacturers contracts to produce BCG. Along with supply availability from existing manufacturers, and a "new WHO prequalified vaccine" the total supply will be "sufficient to meet both suppressed 2015 demand carried over to 2016, as well as total forecast demand through 2016–2018." Supply shortage. In 2011, the Sanofi Pasteur plant flooded, causing problems with mold. The facility, located in Toronto, Ontario, Canada, produced BCG vaccine products made with substrain Connaught such as a tuberculosis vaccine and ImmuCYST, a BCG immunotherapeutic and bladder cancer drug. By April 2012 the FDA had found dozens of documented problems with sterility at the plant including mold, nesting birds and rusted electrical conduits. The resulting closure of the plant for over two years caused shortages of bladder cancer and tuberculosis vaccines. On 29 October 2014 Health Canada gave the permission for Sanofi to resume production of BCG. A 2018 analysis of the global supply concluded that the supplies are adequate to meet forecast BCG vaccine demand, but that risks of shortages remain, mainly due to dependence of 75 percent of WHO pre-qualified supply on just two suppliers.
Dried. Some BCG vaccines are freeze dried and become fine powder. Sometimes the powder is sealed with vacuum in a glass ampoule. Such a glass ampoule has to be opened slowly to prevent the airflow from blowing out the powder. Then the powder has to be diluted with saline water before injecting. History. The history of BCG is tied to that of smallpox. By 1865 Jean Antoine Villemin had demonstrated that rabbits could be infected with tuberculosis from humans; by 1868 he had found that rabbits could be infected with tuberculosis from cows and that rabbits could be infected with tuberculosis from other rabbits. Thus, he concluded that tuberculosis was transmitted via some unidentified microorganism (or "virus", as he called it). In 1882 Robert Koch regarded human and bovine tuberculosis as identical. But in 1895, Theobald Smith presented differences between human and bovine tuberculosis, which he reported to Koch. By 1901 Koch distinguished "Mycobacterium bovis" from "Mycobacterium tuberculosis". Following the success of vaccination in preventing smallpox, established during the 18th century, scientists thought to find a corollary in tuberculosis by drawing a parallel between bovine tuberculosis and cowpox: it was hypothesized that infection with bovine tuberculosis might protect against infection with human tuberculosis. In the late 19th century, clinical trials using "M. bovis" were conducted in Italy with disastrous results, because "M. bovis" was found to be just as virulent as "M. tuberculosis".
Albert Calmette, a French physician and bacteriologist, and his assistant and later colleague, Camille Guérin, a veterinarian, were working at the Institut Pasteur de Lille (Lille, France) in 1908. Their work included subculturing virulent strains of the tuberculosis bacillus and testing different culture media. They noted a glycerin-bile-potato mixture grew bacilli that seemed less virulent and changed the course of their research to see if repeated subculturing would produce a strain that was attenuated enough to be considered for use as a vaccine. The BCG strain was isolated after subculturing 239 times during 13 years from a virulent strain on glycerine potato medium. The research continued throughout World War I until 1919 when the now avirulent bacilli were unable to cause tuberculosis disease in research animals. Calmette and Guerin transferred to the Paris Pasteur Institute in 1919. The BCG vaccine was first used in humans in 1921. Public acceptance was slow, and the Lübeck disaster, in particular, did much to harm it. Between 1929 and 1933 in Lübeck, 251 infants were vaccinated in the first 10 days of life; 173 developed tuberculosis and 72 died. It was subsequently discovered that the BCG administered there had been contaminated with a virulent strain that was being stored in the same incubator, which led to legal action against the vaccine's manufacturers.
Dr. R. G. Ferguson, working at the Fort Qu'Appelle Sanatorium in Saskatchewan, was among the pioneers in developing the practice of vaccination against tuberculosis. In Canada, more than 600 children from residential schools were used as involuntary participants in BCG vaccine trials between 1933 and 1945. In 1928, the BCG vaccine was adopted by the Health Committee of the League of Nations (predecessor to the World Health Organization (WHO)). Because of opposition, however, it only became widely used after World War II. From 1945 to 1948, relief organizations (International Tuberculosis Campaign or Joint Enterprises) vaccinated over eight million babies in Eastern Europe and prevented the predicted typical increase of tuberculosis after a major war. The BCG vaccine is very efficacious against tuberculous meningitis in the pediatric age group, but its efficacy against pulmonary tuberculosis appears variable. Some countries have removed the BCG vaccine from routine vaccination. Two countries that have never used it routinely are the United States and the Netherlands (in both countries, it is felt that having a reliable Mantoux test and therefore being able to accurately detect active disease is more beneficial to society than vaccinating against a relatively rare condition).
Other names include "Vaccin Bilié de Calmette et Guérin vaccine" and "Bacille de Calmette et Guérin vaccine". Research. Tentative evidence exists for a beneficial non-specific effect of BCG vaccination on overall mortality in low-income countries, or for its reducing other health problems including sepsis and respiratory infections when given early, with greater benefit the earlier it is used. In rhesus macaques, BCG shows improved rates of protection when given intravenously. Some risks must be evaluated before it can be translated to humans. The University of Oxford Jenner Institute is conducting a study comparing the efficacy of injected versus inhaled BCG vaccine in already-vaccinated adults. Type 1 diabetes. , BCG vaccine is in the early stages of being studied in type 1 diabetes (T1D). COVID-19. Use of the BCG vaccine may provide protection against COVID-19. However, epidemiologic observations in this respect are ambiguous. The WHO does not recommend its use for prevention . , 20 BCG trials are in various clinical stages. , the results are extremely mixed. A 15-month trial involving people thrice-vaccinated over the two years before the pandemic shows positive results in preventing infection in BCG-naive people with type 1 diabetes. On the other hand, a 5-month trial shows that re-vaccinating with BCG does not help prevent infection in healthcare workers. Both of these trials were double-blind randomized controlled trials.
Bunsen Bunsen may refer to:
Common buzzard The common buzzard (Buteo buteo) is a medium-to-large bird of prey which has a large range. It is a member of the genus "Buteo" in the family Accipitridae. The species lives in most of Europe and extends its breeding range across much of the Palearctic as far as northwestern China (Tian Shan), far western Siberia and northwestern Mongolia. Over much of its range, it is a year-round resident. However, buzzards from the colder parts of the Northern Hemisphere as well as those that breed in the eastern part of their range typically migrate south for the northern winter, many journeying as far as South Africa. The common buzzard is an opportunistic predator that can take a wide variety of prey, but it feeds mostly on small mammals, especially rodents such as voles. It typically hunts from a perch. Like most accipitrid birds of prey, it builds a nest, typically in trees in this species, and is a devoted parent to a relatively small brood of young. The common buzzard appears to be the most common diurnal raptor in Europe, as estimates of its total global population run well into the millions.
Taxonomy. The first formal description of the common buzzard was by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his "Systema Naturae" under the binomial name "Falco buteo". The genus "Buteo" was introduced by the French naturalist Bernard Germain de Lacépède in 1799 by tautonymy with the specific name of this species. The word "buteo" is Latin for a buzzard. It should not be confused with the Turkey vulture, which is sometimes called a buzzard in American English. The Buteoninae subfamily originated from and is most diversified in the Americas, with occasional broader radiations that led to common buzzards and other Eurasian and African buzzards. The common buzzard is a member of the genus "Buteo", a group of medium-sized raptors with robust bodies and broad wings. The "Buteo" species of Eurasia and Africa are usually commonly referred to as "buzzards" while those in the Americas are called hawks.
The "Buteo" species of Eurasia and Africa are usually commonly referred to as "buzzards" while those in the Americas are called hawks. The two species may belong to the same species complex. Three buzzards in Africa are likely closely related to the common buzzard based on genetic materials, the Mountain buzzard ("Buteo oreophilus"), Forest buzzards ("Buteo trizonatus") and the Madagascar buzzard ("Buteo brachypterus"), to the point where it has been questioned whether they are sufficiently distinct to qualify as full species. However, the distinctiveness of these African buzzards has generally been supported. Genetic studies have further indicated that the modern buzzards of Eurasia and Africa are a relatively young group, showing that they diverged at about 300,000 years ago. Nonetheless, fossils dating earlier than 5 million year old (the late Miocene period) showed "Buteo" species were present in Europe much earlier than that would imply, although it cannot be stated to a certainty that these would have been related to the extant buzzards.
Subspecies and species splits. Some 16 subspecies have been described in the past and up to 11 are often considered valid, although some authorities accept as few as seven. Common buzzard subspecies fall into two groups. The western "buteo" group is mainly resident or short-distance migrants and includes: The eastern "vulpinus" group includes: At one time, races of the common buzzard were thought to range as far in Asia as a breeding bird well into the Himalayas and as far east as northeastern China, Russia to the Sea of Okhotsk, and all the islands of the Kurile Islands and of Japan, despite both the Himalayan and eastern birds showing a natural gap in distribution from the next nearest breeding common buzzard. However, DNA testing has revealed that the buzzards of these populations probably belong to different species. Most authorities now accept these buzzards as full species: the eastern buzzard ("Buteo japonicus"; with three subspecies of its own) and the Himalayan buzzard ("Buteo refectus"). Buzzards found on the islands of Cape Verde off of the coast of western Africa, once referred to as the subspecies "B. b. bannermani", and Socotra Island off of the northern peninsula of Arabia, once referred to as the rarely recognized subspecies "B. b. socotrae", are now generally thought not to belong to the common buzzard. DNA testing has indicated that these insular buzzards are actually more closely related to the long-legged buzzard ("Buteo rufinus") than to the common buzzard. Subsequently, some researchers have advocated full species status for the Cape Verde population, but the placement of these buzzards is generally deemed unclear.
Description. The common buzzard is a medium to large sized raptor that is highly variable in plumage. Most buzzards are distinctly round headed with a somewhat slender bill, relatively long wings that either reach or fall slightly short of the tail tip when perched, a fairly short tail, and somewhat short and mainly bare tarsi. They can appear fairly compact in overall appearance but may also appear large relative to other more common raptorial birds such as kestrels and sparrowhawks. The common buzzard measures between in length with a wingspan. Females average about 2–7% larger than males linearly and weigh about 15% more. Body mass can show considerable variation. Buzzards from Great Britain alone can vary from in males, while females there can range from .
Beyond the nominate form ("B. b. buteo") that occupies most of the common buzzard's European range, a second main, widely distributed subspecies is known as the steppe buzzard ("B. b. vulpinus"). The steppe buzzard race shows three main colour morphs, each of which can be predominant in a region of breeding range. It is more distinctly polymorphic rather than just individually very variable like the nominate race. This may be because, unlike the nominate buzzard, the steppe buzzard is highly migratory. Polymorphism has been linked with migratory behaviour. The most common type of steppe buzzard is the rufous morph which gives this subspecies its scientific name ("vulpes" is Latin for "fox"). This morph comprises a majority of birds seen in passage east of the Mediterranean. Rufous morph buzzards are a paler grey-brown above than most nominate "B. b. buteo". Compared to the nominate race, rufous "vulpinus" show a patterning not dissimilar but generally far more rufous-toned on head, the fringes to mantle wing coverts and, especially, on the tail and the underside.
buteo". Compared to the nominate race, rufous "vulpinus" show a patterning not dissimilar but generally far more rufous-toned on head, the fringes to mantle wing coverts and, especially, on the tail and the underside. The head is grey-brown with rufous tinges usually while the tail is rufous and can vary from almost unmarked to thinly dark-barred with a subterminal band. The underside can be uniformly pale to dark rufous, barred heavily or lightly with rufous or with dusky barring, usually with darker individuals showing the U as in nominate but with a rufous hue. The pale morph of the steppe buzzard is commonest in the west of its subspecies range, predominantly seen in winter and migration at the various land bridge of the Mediterranean. As in the rufous morph, the pale morph "vulpinus" is grey-brown above but the tail is generally marked with thin dark bars and a subterminal band, only showing rufous near the tip. The underside in the pale morph is greyish-white with dark grey-brown or somewhat streaked head to chest and barred belly and chest, occasionally showing darker flanks that can be somewhat rufous.
The underside in the pale morph is greyish-white with dark grey-brown or somewhat streaked head to chest and barred belly and chest, occasionally showing darker flanks that can be somewhat rufous. Dark morph "vulpinus" tend to be found in the east and southeast of the subspecies range and are easily outnumbered by rufous morph while largely using similar migration points. Dark morph individuals vary from grey-brown to much darker blackish-brown, and have a tail that is dark grey or somewhat mixed grey and rufous, is distinctly marked with dark barring and has a broad, black subterminal band. Dark morph "vulpinus" have a head and underside that is mostly uniform dark, from dark brown to blackish-brown to almost pure black. Rufous morph juveniles are often distinctly paler in ground colour (ranging even to creamy-grey) than adults with distinct barring below actually increased in pale morph type juvenile. Pale and rufous morph juveniles can only be distinguished from each other in extreme cases. Dark morph juveniles are more similar to adult dark morph "vulpinus" but often show a little whitish streaking below, and like all other races have lighter coloured eyes and more evenly barred tails than adults.
Dark morph juveniles are more similar to adult dark morph "vulpinus" but often show a little whitish streaking below, and like all other races have lighter coloured eyes and more evenly barred tails than adults. Steppe buzzards tend to appear smaller and more agile in flight than nominate whose wing beats can look slower and clumsier. In flight, rufous morph "vulpinus" have their whole body and underwing varying from uniform to patterned rufous (if patterning present, it is variable, but can be on chest and often thighs, sometimes flanks, pale band across median coverts), while the under-tail usually paler rufous than above. Whitish flight feathers are more prominent than in nominate and more marked contrast with the bold dark brown band along the trailing edges. Markings of pale "vulpinus" as seen in flight are similar to rufous morph (such as paler wing markings) but more greyish both on wings and body. In dark morph "vulpinus" the broad black trailing edges and colour of body make whitish areas of inner wing stand out further with an often bolder and blacker carpal patch than in other morphs.
In dark morph "vulpinus" the broad black trailing edges and colour of body make whitish areas of inner wing stand out further with an often bolder and blacker carpal patch than in other morphs. As in nominate, juvenile "vulpinus" (rufous/pale) tend to have much less distinct trailing edges, general streaking on body and along median underwing coverts. Dark morph "vulpinus" resemble adult in flight more so than other morphs. Similar species. The common buzzard is often confused with other raptors especially in flight or at a distance. Inexperienced and over-enthusiastic observers have even mistaken darker birds for the far larger and differently proportioned golden eagle ("Aquila chrysaetos") and also dark birds for western marsh harrier ("Circus aeruginosus") which also flies in a dihedral but is obviously relatively much longer and slenderer winged and tailed and with far different flying methods.
Inexperienced and over-enthusiastic observers have even mistaken darker birds for the far larger and differently proportioned golden eagle ("Aquila chrysaetos") and also dark birds for western marsh harrier ("Circus aeruginosus") which also flies in a dihedral but is obviously relatively much longer and slenderer winged and tailed and with far different flying methods. Pale individuals are sometimes also mistaken with pale morph short-toed eagles ("Circaetus gallicus") which are much larger with a considerably bigger head, longer wings (which are usually held evenly in flight rather than in a dihedral) and paler underwing lacking any carpal patch or dark wing lining. More serious identification concerns lie in other "Buteo" species and in flight with honey buzzards, which are quite different looking when seen perched at close range. The European honey buzzard ("Pernis apivorus") is thought in engage in mimicry of more powerful raptors, in particular, juveniles may mimic the plumage of the more powerful common buzzard.
The European honey buzzard ("Pernis apivorus") is thought in engage in mimicry of more powerful raptors, in particular, juveniles may mimic the plumage of the more powerful common buzzard. While less individually variable in Europe, the honey buzzard is more extensive polymorphic on underparts than even the common buzzard. The most common morph of the adult European honey buzzard is heavily and rufous barred on the underside, quite different from the common buzzard, however the brownish juvenile much more resembles an intermediate common buzzard. Honey buzzards flap with distinctively slower and more even wing beats than common buzzard. The wings are also lifted higher on each upstroke, creating a more regular and mechanical effect, furthermore their wings are held slightly arched when soaring but not in a V. On the honey buzzard, the head appears smaller, the body thinner, the tail longer and the wings narrower and more parallel edged. The steppe buzzard race is particularly often mistaken for juvenile European honey buzzards, to the point where early observers of raptor migration in Israel considered distant individuals indistinguishable.
The steppe buzzard race is particularly often mistaken for juvenile European honey buzzards, to the point where early observers of raptor migration in Israel considered distant individuals indistinguishable. However, when compared to a steppe buzzard, the honey buzzard has distinctly darker secondaries on the underwing with fewer and broader bars and more extensive black wing-tips (whole fingers) contrasting with a less extensively pale hand. Found in the same range as the steppe buzzard in some parts of southern Siberia as well as (with wintering steppes) in southwestern India, the Oriental honey buzzard ("Pernis ptilorhynchus") is larger than both the European honey buzzard and the common buzzard. The oriental species is with more similar in body plan to common buzzards, being relatively broader winged, shorter tailed and more amply-headed (though the head is still relatively small) relative to the European honey buzzard, but all plumages lack carpal patches.
In much of Europe, the common buzzard is the only type of buzzard. However, the subarctic breeding rough-legged buzzard ("Buteo lagopus") comes down to occupy much of the northern part of the continent during winter in the same haunts as the common buzzard. However, the rough-legged buzzard is typically larger and distinctly longer-winged with feathered legs, as well as having a white based tail with a broad subterminal band. Rough-legged buzzards have slower wing beats and hover far more frequently than do common buzzards. The carpal patch marking on the under-wing are also bolder and blacker on all paler forms of rough-legged hawk. Many pale morph rough-legged buzzards have a bold, blackish band across the belly against contrasting paler feathers, a feature which rarely appears in individual common buzzard. Usually the face also appears somewhat whitish in most pale morphs of rough-legged buzzards, which is true of only extremely pale common buzzards. Dark morph rough-legged buzzards are usually distinctly darker (ranging to almost blackish) than even extreme dark individuals of common buzzards in Europe and still have the distinct white-based tail and broad subterminal band of other roughlegs.
Dark morph rough-legged buzzards are usually distinctly darker (ranging to almost blackish) than even extreme dark individuals of common buzzards in Europe and still have the distinct white-based tail and broad subterminal band of other roughlegs. In eastern Europe and much of the Asian range of common buzzards, the long-legged buzzard ("Buteo rufinus") may live alongside the common species. As in the steppe buzzard race, the long-legged buzzard has three main colour morphs that are more or less similar in hue. In both the steppe buzzard race and long-legged buzzard, the main colour is overall fairly rufous. More so than steppe buzzards, long-legged buzzards tend to have a distinctly paler head and neck compared to other feathers, and, more distinctly, a normally unbarred tail. Furthermore, the long-legged buzzard is usually a rather larger bird, often considered fairly eagle-like in appearance (although it does appear gracile and small-billed even compared to smaller true eagles), an effect enhanced by its longer tarsi, somewhat longer neck and relatively elongated wings.
Furthermore, the long-legged buzzard is usually a rather larger bird, often considered fairly eagle-like in appearance (although it does appear gracile and small-billed even compared to smaller true eagles), an effect enhanced by its longer tarsi, somewhat longer neck and relatively elongated wings. The flight style of the latter species is deeper, slower and more aquiline, with much more frequent hovering, showing a more protruding head and a slightly higher V held in a soar. The smaller North African and Arabian race of long-legged buzzard ("B. r. cirtensis") is more similar in size and nearly all colour characteristics to steppe buzzard, extending to the heavily streaked juvenile plumage, in some cases such birds can be distinguished only by their proportions and flight patterns which remain unchanged. Hybridization with the latter race ("B. r. cirtensis") and nominate common buzzards has been observed in the Strait of Gibraltar, a few such birds have been reported potentially in the southern Mediterranean due to mutually encroaching ranges, which are blurring possibly due to climate change.
Wintering steppe buzzards may live alongside mountain buzzards and especially with forest buzzard while wintering in Africa. The juveniles of steppe and forest buzzards are more or less indistinguishable and only told apart by proportions and flight style, the latter species being smaller, more compact, having a smaller bill, shorter legs and shorter and thinner wings than a steppe buzzard. However, size is not diagnostic unless side by side as the two buzzards overlap in this regard. Most reliable are the species wing proportions and their flight actions. Forest buzzard have more flexible wing beats interspersed with glides, additionally soaring on flatter wings and apparently never engage in hovering. Adult forest buzzards compared to the typical adult steppe buzzard (rufous morph) are also similar, but the forest typically has a whiter underside, sometimes mostly plain white, usually with heavy blotches or drop-shaped marks on abdomen, with barring on thighs, more narrow tear-shaped on chest and more spotted on leading edges of underwing,
with barring on thighs, more narrow tear-shaped on chest and more spotted on leading edges of underwing, usually lacking marking on the white U across chest (which is otherwise similar but usually broader than that of "vulpinus"). In comparison, the mountain buzzard, which is more similar in size to the steppe buzzard and slightly larger than the forest buzzard, is usually duller brown above than a steppe buzzard and is more whitish below with distinctive heavy brown blotches from breasts to the belly, flanks and wing linings while juvenile mountain buzzard is buffy below with smaller and streakier markings. The steppe buzzard when compared to another African species, the red-necked buzzard ("Buteo auguralis"), which has red tail similar to "vulpinus", is distinct in all other plumage aspects despite their similar size. The latter buzzard has a streaky rufous head and is white below with a contrasting bold dark chest in adult plumage and, in juvenile plumage, has heavy, dark blotches on the chest and flanks with pale wing-linings.
The latter buzzard has a streaky rufous head and is white below with a contrasting bold dark chest in adult plumage and, in juvenile plumage, has heavy, dark blotches on the chest and flanks with pale wing-linings. Jackal and augur buzzards ("Buteo rufofuscus" & "augur"), also both rufous on the tail, are larger and bulkier than steppe buzzards and have several distinctive plumage characteristics, most notably both having their own striking, contrasting patterns of black-brown, rufous and cream. Distribution and habitat. The common buzzard is found throughout several islands in the eastern Atlantic islands, including the Canary Islands and Azores and almost throughout Europe. It is today found in Ireland and in nearly every part of Scotland, Wales and England. In mainland Europe, remarkably, there are no substantial gaps without breeding common buzzards from Portugal and Spain to Greece, Estonia, Belarus and Ukraine, though are present mainly only in the breeding season in much of the eastern half of the latter three countries. They are also present in all larger Mediterranean islands such as Corsica, Sardinia, Sicily and Crete. Further north in Scandinavia, they are found mainly in southeastern Norway (though also some points in southwestern Norway close to the coast and one section north of Trondheim), just over the southern half of Sweden and hugging over the Gulf of Bothnia to Finland where they live as a breeding species over nearly two-thirds of the land.
The common buzzard reaches its northern limits as a breeder in far eastern Finland and over the border to European Russia, continuing as a breeder over to the narrowest straits of the White Sea and nearly to the Kola Peninsula. In these northern quarters, the common buzzard is present typically only in summer but is a year-around resident of a hearty bit of southern Sweden and some of southern Norway. Outside of Europe, it is a resident of northern Turkey (largely close to the Black Sea) otherwise occurring mainly as a passage migrant or winter visitor in the remainder of Turkey, Georgia, sporadically but not rarely in Azerbaijan and Armenia, northern Iran (largely hugging the Caspian Sea) to northern Turkmenistan. Further north though its absent from either side of the northern Caspian Sea, the common buzzard is found in much of western Russia (though exclusively as a breeder) including all of the Central Federal District and the Volga Federal District, all but the northernmost parts of the Northwestern and Ural Federal Districts and nearly the southern half of the Siberian Federal District, its farthest easterly occurrence as a breeder. It also found in northern Kazakhstan, Kyrgyzstan, far northwestern China (Tien Shan) and northwestern Mongolia.
Non-breeding populations occur, either as migrants or wintering birds, in southwestern India, Israel, Lebanon, Syria, Egypt (northeastern), northern Tunisia (and far northwestern Algeria), northern Morocco, near the coasts of The Gambia, Senegal and far southwestern Mauritania and Ivory Coast (and bordering Burkina Faso). In eastern and central Africa, it is found in winter from southeastern Sudan, Eritrea, about two-thirds of Ethiopia, much of Kenya (though apparently absent from the northeast and northwest), Uganda, southern and eastern Democratic Republic of the Congo, and more or less the entirety of southern Africa from Angola across to Tanzania down the remainder of the continent (but for an apparent gap along the coast from southwestern Angola to northwestern South Africa). Habitat.
Behaviour. The common buzzard is a typical "Buteo" in much of its behaviour. It is most often seen either soaring at varying heights or perched prominently on tree tops, bare branches, telegraph poles, fence posts, rocks or ledges, or alternately well inside tree canopies. Buzzards will also stand and forage on the ground. In resident populations, it may spend more than half of its day inactively perched. Furthermore, it has been described a "sluggish and not very bold" bird of prey. It is a gifted soarer once aloft and can do so for extended periods but can appear laborious and heavy in level flight, more so nominate buzzards than steppe buzzards. Particularly in migration, as was recorded in the case of steppe buzzards' movement over Israel, buzzards readily adjust their direction, tail and wing placement and flying height to adjust for the surrounding environment and wind conditions. In Israel, migrant buzzards rarely soar all that high (maximum above ground) due to the lack of mountain ridges that in other areas typically produce flyways; however tail-winds are significant and allow birds to cover a mean of .
Migration. The common buzzard is aptly described as a partial migrant. The autumn and spring movements of buzzards are subject to extensive variation, even down to the individual level, based on a region's food resources, competition (both from other buzzards and other predators), extent of human disturbance and weather conditions. Short-distance movements are the norm for juveniles and some adults in autumn and winter, but more adults in central Europe and the British Isles remain on their year-around residence than do not. Even for first year juvenile buzzards dispersal may not take them very far. In England, 96% of first-years moved in winter to less than from their natal site. Southwestern Poland was recorded to be a fairly important wintering grounds for central European buzzards in early spring that apparently travelled from somewhat farther north, in winter average density was a locally high 2.12 individual per square kilometer. Habitat and prey availability seemed to be the primary drivers of habitat selection in fall for European buzzards.
Habitat and prey availability seemed to be the primary drivers of habitat selection in fall for European buzzards. In northern Germany, buzzards were recorded to show preferences in fall for areas fairly distant from nesting site, with a large quantity of vole-holes and more widely dispersed perches. In Bulgaria, the mean wintering density was 0.34 individual per square kilometer, and buzzards showed a preference for agricultural over forested areas. Similar habitat preferences were recorded in northeastern Romania, where buzzard density was 0.334–0.539 individuals per square kilometer. The nominate buzzards of Scandinavia are somewhat more strongly migratory than most central European populations. However, birds from Sweden show some variation in migratory behaviours. A maximum of 41,000 individuals have been recorded at one of the main migration sites within southern Sweden in Falsterbo. In southern Sweden, winter movements and migration was studied via observation of buzzard colour. White individuals were substantially more common in southern Sweden rather than further north in their Swedish range.
White individuals were substantially more common in southern Sweden rather than further north in their Swedish range. The southern population migrates earlier than intermediate to dark buzzards, in both adults and juveniles. A larger proportion of juveniles than of adults migrate in the southern population. Especially adults in the southern population are resident to a higher degree than more northerly breeders. The entire population of the steppe buzzard is strongly migratory, covering substantial distances during migration. In no part of the range do steppe buzzards use the same summering and wintering grounds. Steppe buzzards are slightly gregarious in migration, and travel in variously sized flocks. This race migrates in September to October often from Asia Minor to the Cape of Africa in about a month but does not cross water, following around the Winam Gulf of Lake Victoria rather than crossing the several kilometer wide gulf. Similarly, they will funnel along both sides of the Black Sea.
This race migrates in September to October often from Asia Minor to the Cape of Africa in about a month but does not cross water, following around the Winam Gulf of Lake Victoria rather than crossing the several kilometer wide gulf. Similarly, they will funnel along both sides of the Black Sea. Migrating steppe buzzards will rise up with the morning thermals and can cover an average of hundreds of miles a day using the available currents along mountain ridges and other topographic features. The spring migration for steppe buzzards peaks around March–April, but the latest "vulpinus" arrive in their breeding grounds by late April or early May. Distances covered by migrating steppe buzzards in one way flights from northern Europe (i.e. Finland or Sweden) to southern Africa have ranged over within a season . For the steppe buzzards from eastern and northern Europe and western Russia (which compromise a majority of all steppe buzzards), peak migratory numbers occur in differing areas in autumn, when the largest recorded movements occurs through Asia Minor such as Turkey, than in spring, when the largest recorded movement are to the south in the Middle East, especially Israel.
than in spring, when the largest recorded movement are to the south in the Middle East, especially Israel. The two migratory movements barely differ overall until they reach the Middle East and east Africa, where the largest volume of migrants in autumn occurs at the southern part of the Red Sea, around Djibouti and Yemen, while the main volume in spring is in the northernmost strait, around Egypt and Israel. In autumn, numbers of steppe buzzards recorded in migration have ranged up to 32,000 (recorded 1971) in northwestern Turkey (Bosporus) and in northeastern Turkey (Black Sea) up to 205,000 (recorded 1976). Further down in migration, autumn numbers of up to 98,000 have been recorded in passage in Djibouti. Between 150,000 and nearly 466,000 Steppe Buzzard have been recorded migrating through Israel during spring, making this not only the most abundant migratory raptor here but one of the largest raptor migrations anywhere in the world. Migratory movements of southern Africa buzzards largely occur along the major mountain ranges, such as the Drakensberg and Lebombo Mountains.
Migratory movements of southern Africa buzzards largely occur along the major mountain ranges, such as the Drakensberg and Lebombo Mountains. Wintering steppe buzzards occur far more irregularly in Transvaal than Cape region in winter. The onset of migratory movement for steppe buzzards back to the breeding grounds in southern Africa is mainly in March, peaking in the second week. Steppe buzzard molt their feathers rapidly upon arrival at wintering grounds and seems to split their flight feather molt between breeding ground in Eurasia and wintering ground in southern Africa, the molt pausing during migration. In last 50 years, it was recorded that nominate buzzards are typically migrating shorter distances and wintering further north, possibly in response to climate change, resulting in relatively smaller numbers of them at migration sites. They are also extending their breeding range possibly reducing/supplanting steppe buzzards.
Vocalizations. Resident populations of common buzzards tend to vocalize all year around, whereas migrants tend to vocalize only during the breeding season. Both nominate buzzards and steppe buzzards (and their numerous related subspecies within their types) tend to have similar voices. The main call of the species is a plaintive, far-carrying "pee-yow" or "peee-oo", used as both contact call and more excitedly in aerial displays. Their call is sharper, more ringing when used in aggression, tends to be more drawn-out and wavering when chasing intruders, sharper, more yelping when as warning when approaching the nest or shorter and more explosive when called in alarm. Other variations of their vocal performances include a cat-like "mew", uttered repeatedly on the wing or when perched, especially in display; a repeated "mah" has been recorded as uttered by pairs answering each other, further chuckles and croaks have also been recorded at nests. Juveniles can usually be distinguished by the discordant nature of their calls compared to those of adults.
Dietary biology. The common buzzard is a generalist predator which hunts a wide variety of prey given the opportunity. Their prey spectrum extents to a wide variety of vertebrates including mammals, birds (from any age from eggs to adult birds), reptiles, amphibians and, rarely, fish, as well as to various invertebrates, mostly insects. Young animals are often attacked, largely the nidifugous young of various vertebrates. In total well over 300 prey species are known to be taken by common buzzards. Furthermore, prey size can vary from tiny beetles, caterpillars and ants to large adult grouse and rabbits up to nearly twice their body mass. Mean body mass of vertebrate prey was estimated at in Belarus. At times, they will also subsist partially on carrion, usually of dead mammals or fish. However, dietary studies have shown that they mostly prey upon small mammals, largely small rodents. Like many temperate zone raptorial birds of varied lineages, voles are an essential part of the common buzzard's diet. This bird's preference for the interface between woods and open areas frequently puts them in ideal vole habitat.
This bird's preference for the interface between woods and open areas frequently puts them in ideal vole habitat. Hunting in relatively open areas has been found to increase hunting success whereas more complete shrub cover lowered success. A majority of prey is taken by dropping from perch, and is normally taken on ground. Alternately, prey may be hunted in a low flight. This species tends not to hunt in a spectacular stoop but generally drops gently then gradually accelerate at bottom with wings held above the back. Sometimes, the buzzard also forages by random glides or soars over open country, wood edges or clearings. Perch hunting may be done preferentially but buzzards fairly regularly also hunt from a ground position when the habitat demands it. Outside the breeding season, as many 15–30 buzzards have been recorded foraging on ground in a single large field, especially juveniles. Normally the rarest foraging type is hovering. A study from Great Britain indicated that hovering does not seem to increase hunting success.
Mammals. A high diversity of rodents may be taken given the chance, as around 60 species of rodent have been recorded in the foods of common buzzards. It seems clear that voles are the most significant prey type for European buzzards. Nearly every study from the continent makes reference to the importance, in particular, of the two most numerous and widely distributed European voles: the common vole ("Microtus arvalis") and the somewhat more northerly ranging field vole ("Microtus agrestis"). In southern Scotland, field voles were the best-represented species in pellets, accounting for 32.1% of 581 pellets. In southern Norway, field voles were again the main food in years with peak vole numbers, accounting for 40.8% of 179 prey items in 1985 and 24.7% of 332 prey items in 1994. Altogether, rodents amount to 67.6% and 58.4% of the foods in these respective peak vole years. However, in low vole population years, the contribution of rodents to the diet was minor. As far west as the Netherlands, common voles were the most regular prey, amounting to 19.6% of 6624 prey items in a very large study. Common voles were the main foods recorded in central Slovakia, accounting for 26.5% of 606 prey items. The common vole, or other related vole species at times, were the main foods as well in Ukraine (17.2% of 146 prey items) ranging east to Russia in the Privolshky Steppe Nature Reserve (41.8% of 74 prey items) and in Samara (21.4% of 183 prey items). Other records from Russia and Ukraine show voles ranging from slightly secondary prey to as much as 42.2% of the diet. In Belarus, voles, including "Microtus" species and bank voles ("Myodes glareolus"), accounted for 34.8% of the biomass on average in 1065 prey items from different study areas over 4 years. At least 12 species of the genus "Microtus" are known to be hunted by common buzzards and even this is probably conservative, moreover similar species like lemmings will be taken if available.
Other rodents are taken largely opportunistically rather than by preference. Several wood mice ("Apodemus ssp.") are known to be taken quite frequently but given their preference for activity in deeper woods than the field-forest interfaces preferred, they are rarely more than secondary food items. An exception was in Samara where the yellow-necked mouse ("Apodemus flavicollis"), one of the largest of its genus at , made up 20.9%, putting it just behind the common vole in importance. Similarly, tree squirrels are readily taken but rarely important in the foods of buzzards in Europe, as buzzards apparently prefer to avoid taking prey from trees nor do they possess the agility typically necessary to capture significant quantities of tree squirrels. All four ground squirrels that range (mostly) into eastern Europe are also known to be common buzzard prey but little quantitative analysis has gone into how significant such predator-prey relations are. Rodent prey taken have ranged in size from the Eurasian harvest mouse ("Micromys minutus") to the non-native, muskrat ("Ondatra zibethicus"). Other rodents taken either seldom or in areas where the food habits of buzzards are spottily known include flying squirrels, marmots (presumably very young if taken alive), chipmunks, spiny rats, hamsters, mole-rats, gerbils, jirds and jerboas and occasionally hearty numbers of dormice, although these are nocturnal. Surprisingly little research has gone into the diets of wintering steppe buzzards in southern Africa, considering their numerous status there. However, it has been indicated that the main prey remains consist of rodents such as the four-striped grass mouse ("Rhabdomys pumilio") and Cape mole-rats ("Georychus capensis").
Other than rodents, two other groups of mammals can be counted as significant to the diet of common buzzards. One of these main prey types of import in the diets of common buzzards are leporids or lagomorphs, especially the European rabbit ("Oryctolagus cuniculus") where it is found in numbers in a wild or feral state. In all dietary studies from Scotland, rabbits were highly important to the buzzard's diet. In southern Scotland, rabbits constituted 40.8% of remains at nests and 21.6% of pellet contents, while lagomorphs (mainly rabbits but also some young hares) were present in 99% of remains in Moray, Scotland. The nutritional richness relative to the commonest prey elsewhere, such as voles, might account for the high productivity of buzzards here. For example, clutch sizes were twice as large on average where rabbits were common (Moray) than were where they were rare (Glen Urquhart). In northern Ireland, an area of interest because it is devoid of any native vole species, rabbits were again the main prey.
For example, clutch sizes were twice as large on average where rabbits were common (Moray) than were where they were rare (Glen Urquhart). In northern Ireland, an area of interest because it is devoid of any native vole species, rabbits were again the main prey. Here, lagomorphs constituted 22.5% of prey items by number and 43.7% by biomass. While rabbits are non-native, albeit long-established, in the British Isles, in their native area of the Iberian peninsula, rabbits are similarly significant to the buzzard's diet. In Murcia, Spain, rabbits were the most common mammal in the diet, making up 16.8% of 167 prey items. In a large study from northeastern Spain, rabbits were dominant in the buzzard's foods, making up 66.5% of 598 prey items. In the Netherlands, European rabbits were second in number (19.1% of 6624 prey items) only to common voles and the largest contributor of biomass to nests (36.7%). Outside of these (at least historically) rabbit-rich areas, leverets of the common hare species found in Europe can be important supplemental prey.
In the Netherlands, European rabbits were second in number (19.1% of 6624 prey items) only to common voles and the largest contributor of biomass to nests (36.7%). Outside of these (at least historically) rabbit-rich areas, leverets of the common hare species found in Europe can be important supplemental prey. European hare ("Lepus europaeus") were the fourth most important prey species in central Poland and the third most significant prey species in Stavropol Krai, Russia. Buzzards normally attack the young of European rabbits and hares. Most of the rabbits taken by buzzard variously been estimated from , and infrequently up to in weight. Similarly, in different areas and the mean weight of brown hares taken in Finland was around . One young mountain hares ("Lepus timidus") taken in Norway was estimated to about . However, common buzzards are known to kill adult rabbits at times. This can be supported by remains of relatively large-sized tarsus bones of the rabbit, up to 64mm in length.
The other significant mammalian prey type is insectivores, among which more than 20 species are known to be taken by this species, including nearly all the species of shrew, mole and hedgehog found in Europe. Moles are taken particularly often among this order, since as is the case with "vole-holes", buzzards probably tend to watch molehills in fields for activity and dive quickly from their perch when one of the subterranean mammals pops up. The most widely found mole in the buzzard's northern range is the European mole ("Talpa europaea") and this is one of the more important non-rodent prey items for the species. This species was present in 55% of 101 remains in Glen Urquhart, Scotland and was the second most common prey species (18.6%) in 606 prey items in Slovakia. In Bari, Italy, the Roman mole ("Talpa romana"), of similar size to the European species, was the leading identified mammalian prey, making up 10.7% of the diet. The full-size range of insectivores may be taken by buzzards, ranging from the world's smallest mammal (by weight), the Etruscan shrew ("Suncus etruscus") to arguably the heaviest insectivore, the European hedgehog ("Erinaceus europaeus"). Mammalian prey for common buzzards other than rodents, insectivores, and lagomorphs is rarely taken. Occasionally, some weasels such as least weasel ("Mustela nivalis") and stoat ("Mustela erminea") are taken, and remains of young pine martens ("Martes martes") and adult european polecats ("Mustela putorius") was found in buzzard nest. Numerous larger mammals, including medium-sized carnivores such as dogs, cats and foxes and various ungulates, are sometimes eaten as carrion by buzzards, mainly during lean winter months. Still-borns of deer are also visited with some frequency.
Birds. When attacking birds, common buzzards chiefly prey on nestlings and fledglings of small to medium-sized birds, largely passerines but also a variety of gamebirds, but sometimes also injured, sickly or unwary but healthy adults. While capable of overpowering birds larger than itself, the common buzzard is usually considered to lack the agility necessary to capture many adult birds, even gamebirds which would presumably be weaker fliers considering their relatively heavy bodies and small wings. The amount of fledgling and younger birds preyed upon relative to adults is variable, however. For example, in the Italian Alps, 72% of birds taken were fledglings or recently fledged juveniles, 19% were nestlings and 8% were adults. On the contrary, in southern Scotland, even though the buzzards were taking relatively large bird prey, largely red grouse ("Lagopus lagopus scotica"), 87% of birds taken were reportedly adults. In total, as in many raptorial birds that are far from bird-hunting specialists, birds are the most diverse group in the buzzard's prey spectrum due to the sheer number and diversity of birds, few raptors do not hunt them at least occasionally. Nearly 150 species of bird have been identified in the common buzzard's diet. In general, despite many that are taken, birds usually take a secondary position in the diet after mammals. In northern Scotland, birds were fairly numerous in the foods of buzzards. The most often recorded avian prey and 2nd and 3rd most frequent prey species (after only field voles) in Glen Urquhart, were chaffinch ("Fringilla coelebs") and meadow pipits ("Anthus pratensis"), with the buzzards taking 195 fledglings of these species against only 90 adults. This differed from Moray where the most frequent avian prey and 2nd most frequent prey species behind the rabbit was the common wood pigeon ("Columba palumbus") and the buzzards took four times as many adults relative to fledglings.
Birds were the primary food for common buzzards in the Italian Alps, where they made up 46% of the diet against mammal which accounted for 29% in 146 prey items. The leading prey species here were Eurasian blackbirds ("Turdus merula") and Eurasian jays ("Garrulus glandarius"), albeit largely fledglings were taken of both. Birds could also take the leading position in years with low vole populations in southern Norway, in particular thrushes, namely the blackbird, the song thrush ("Turdus philomelos") and the redwing ("Turdus iliacus"), which were collectively 22.1% of 244 prey items in 1993. In southern Spain, birds were equal in number to mammals in the diet, both at 38.3%, but most remains were classified as "unidentified medium-sized birds", although the most often identified species of those that apparently could be determined were Eurasian jays and red-legged partridges ("Alectoris rufa"). Similarly, in northern Ireland, birds were roughly equal in import to mammals but most were unidentified corvids. In Seversky Donets, Ukraine, birds and mammals both made up 39.3% of the foods of buzzards.
birds were roughly equal in import to mammals but most were unidentified corvids. In Seversky Donets, Ukraine, birds and mammals both made up 39.3% of the foods of buzzards. Common buzzards may hunt nearly 80 species passerines and nearly all available gamebirds. Like many other largish raptors, gamebirds are attractive to hunt for buzzards due to their ground-dwelling habits. Buzzards were the most frequent predator in a study of juvenile pheasants in England, accounting for 4.3% of 725 deaths (against 3.2% by foxes, 0.7% by owls and 0.5% by other mammals). They also prey on a wide size range of birds, ranging down to Europe's smallest bird, the goldcrest ("Regulus regulus"). Very few individual birds hunted by buzzards weigh more than . However, there have been some particularly large avian kills by buzzards, including any that weigh more or , or about the largest average size of a buzzard, have including adults of mallard ("Anas platyrhynchos"), black grouse ("Tetrao tetrix"), ring-necked pheasant ("Phasianus colchicus"), common raven ("Corvus corax") and some of the larger gulls if ambushed on their nests.
ring-necked pheasant ("Phasianus colchicus"), common raven ("Corvus corax") and some of the larger gulls if ambushed on their nests. The largest avian kill by a buzzard, and possibly largest known overall for the species, was an adult female western capercaillie ("Tetrao urogallus") that weighed an estimated . At times, buzzards will hunt the young of large birds such as herons and cranes. Other assorted avian prey has included a few species of waterfowl, most available pigeons and doves, cuckoos, swifts, grebes, rails, nearly 20 assorted shorebirds, tubenoses, hoopoes, bee-eaters and several types of woodpecker. Birds with more conspicuous or open nesting areas or habits are more likely to have fledglings or nestlings attacked, such as water birds, while those with more secluded or inaccessible nests, such as pigeons/doves and woodpeckers, adults are more likely to be hunted.
Reptiles and amphibians. The common buzzard may be the most regular avian predator of reptiles and amphibians in Europe apart from the sections where they are sympatric with the largely snake-eating short-toed eagle. In total, the prey spectrum of common buzzards include nearly 50 herpetological prey species. In studies from northern and southern Spain, the leading prey numerically were both reptilian, although in Biscay (northern Spain) the leading prey (19%) was classified as "unidentified snakes". In Murcia, the most numerous prey was the ocellated lizard ("Timon lepidus"), at 32.9%. In total, at Biscay and Murcia, reptiles accounted for 30.4% and 35.9% of the prey items, respectively. Findings were similar in a separate study from northeastern Spain, where reptiles amounted to 35.9% of prey. In Bari, Italy, reptiles were the main prey, making up almost exactly half of the biomass, led by the large green whip snake ("Hierophis viridiflavus"), at 24.2% of food mass. In Stavropol Krai, Russia, the sand lizard ("Lacerta agilis") was the main prey at 23.7% of 55 prey items.
In Stavropol Krai, Russia, the sand lizard ("Lacerta agilis") was the main prey at 23.7% of 55 prey items. The slowworm ("Anguis fragilis"), a legless lizard, became the most numerous prey for the buzzards of southern Norway in low vole years, amounting to 21.3% of 244 prey items in 1993 and were also common even in the peak vole year of 1994 (19% of 332 prey items). More or less any snake in Europe is potential prey and the buzzard has been known to be uncharacteristically bold in going after and overpowering large snakes such as rat snakes, ranging up to nearly in length, and healthy, large vipers despite the danger of being struck by such prey. However, in at least one case, the corpse of a female buzzard was found envenomed over the body of an adder that it had killed. In some parts of range, the common buzzard acquires the habit of taking many frogs and toads. This was the case in the Mogilev Region of Belarus where the moor frog ("Rana arvalis") was the major prey (28.5%) over several years, followed by other frogs and toads amounting to 39.4% of the diet over the years.
This was the case in the Mogilev Region of Belarus where the moor frog ("Rana arvalis") was the major prey (28.5%) over several years, followed by other frogs and toads amounting to 39.4% of the diet over the years. In central Scotland, the common toad ("Bufo bufo") was the most numerous prey species, accounting for 21.7% of 263 prey items, while the common frog ("Rana temporaria") made up a further 14.7% of the diet. Frogs made up about 10% of the diet in central Poland as well. Invertebrates and other prey. When common buzzards feed on invertebrates, these are chiefly earthworms, beetles and caterpillars in Europe and largely seemed to be preyed on by juvenile buzzards with less refined hunting skills or in areas with mild winters and ample swarming or social insects. In most dietary studies, invertebrates are at best a minor supplemental contributor to the buzzard's diet. Nonetheless, roughly a dozen beetle species have found in the foods of buzzards from Ukraine alone. In winter in northeastern Spain, it was found that the buzzards switched largely from the vertebrate prey typically taken during spring and summer to a largely insect-based diet.
In winter in northeastern Spain, it was found that the buzzards switched largely from the vertebrate prey typically taken during spring and summer to a largely insect-based diet. Most of this prey was unidentified but the most frequently identified were European mantis ("Mantis religiosa") and European mole cricket ("Gryllotalpa gryllotalpa"). In Ukraine, 30.8% of the food by number was found to be insects. Especially in winter quarters such as southern Africa, common buzzards are often attracted to swarming locusts and other orthopterans. In this way the steppe buzzard may mirror a similar long-distance migrant from the Americas, the Swainson's hawk, which feeds its young largely on nutritious vertebrates but switches to a largely insect-based once the reach their distant wintering grounds in South America. In Eritrea, 18 returning migrant steppe buzzards were seen to feed together on swarms of grasshoppers. For wintering steppe buzzards in Zimbabwe, one source went so far as to refer to them as primarily insectivorous, apparently being somewhat locally specialized to feeding on termites.
For wintering steppe buzzards in Zimbabwe, one source went so far as to refer to them as primarily insectivorous, apparently being somewhat locally specialized to feeding on termites. Stomach contents in buzzards from Malawi apparently consisted largely of grasshoppers (alternately with lizards). Fish tend to be the rarest class of prey found in the common buzzard's foods. There are a couple cases of predation of fish detected in the Netherlands, while elsewhere they have been known to have fed upon eels and carp. Interspecies predatory relationships. Common buzzards co-occur with dozens of other raptorial birds through their breeding, resident and wintering grounds. There may be many other birds that broadly overlap in prey selection to some extent. Furthermore, their preference for interfaces of forest and field is used heavily by many birds of prey. Some of the most similar species by diet are the common kestrel ("Falco tinniculus"), hen harrier ("Circus cyaenus") and lesser spotted eagle ("Clanga clanga"), not to mention nearly every European species of owl, as all but two may locally prefer rodents such as voles in their diets.
Some of the most similar species by diet are the common kestrel ("Falco tinniculus"), hen harrier ("Circus cyaenus") and lesser spotted eagle ("Clanga clanga"), not to mention nearly every European species of owl, as all but two may locally prefer rodents such as voles in their diets. Diet overlap was found to be extensive between buzzards and red foxes ("Vulpes vulpes") in Poland, with 61.9% of prey selection overlapping by species although the dietary breadth of the fox was broader and more opportunistic. Both fox dens and buzzard roosts were found to be significantly closer to high vole areas relative to the overall environment here. The only other widely found European "Buteo", the rough-legged buzzard, comes to winter extensively with common buzzards. It was found in southern Sweden, habitat, hunting and prey selection often overlapped considerably. Rough-legged buzzards appear to prefer slightly more open habitat and took slightly fewer wood mice than common buzzard. Roughlegs also hover much more frequently and are more given to hunting in high winds.
Rough-legged buzzards appear to prefer slightly more open habitat and took slightly fewer wood mice than common buzzard. Roughlegs also hover much more frequently and are more given to hunting in high winds. The two buzzards are aggressive towards one another and excluded each other from winter feeding territories in similar ways to the way they exclude conspecifics. In northern Germany, the buffer of their habitat preferences apparently accounted for the lack of effect on each other's occupancy between the two buzzard species. Despite a broad range of overlap, very little is known about the ecology of common and long-legged buzzards where they co-exist. However, it can be inferred from the long-legged species preference for predation on differing prey, such as blind mole-rats, ground squirrels, hamsters and gerbils, from the voles usually preferred by the common species, that serious competition for food is unlikely.
A more direct negative effect has been found in buzzard's co-existence with northern goshawk ("Accipiter gentilis"). Despite the considerable discrepancy of the two species dietary habits, habitat selection in Europe is largely similar between buzzards and goshawks. Goshawks are slightly larger than buzzards and are more powerful, agile and generally more aggressive birds, and so they are considered dominant. In studies from Germany and Sweden, buzzards were found to be less disturbance sensitive than goshawks but were probably displaced into inferior nesting spots by the dominant goshawks. The exposure of buzzards to a dummy goshawk was found to decrease breeding success whereas there was no effect on breeding goshawks when they were exposed to a dummy buzzard. In many cases, in Germany and Sweden, goshawks displaced buzzards from their nests to take them over for themselves.
In many cases, in Germany and Sweden, goshawks displaced buzzards from their nests to take them over for themselves. Redtails are not invariably dominated by goshawks and are frequently able to outcompete them by virtue of greater dietary and habitat flexibility. Furthermore, red-tailed hawks are apparently equally capable of killing goshawks as goshawks are of killing them (killings are more one-sided in buzzard-goshawk interactions in favour of the latter). Other raptorial birds, including many of similar or mildly larger size than common buzzards themselves, may dominate or displace the buzzard, especially with aims to take over their nests. Species such as the black kite ("Milvus migrans"), booted eagle ("Hieraeetus pennatus") and the lesser spotted eagle have been known to displace actively nesting buzzards, although in some cases the buzzards may attempt to defend themselves. The broad range of accipitrids that take over buzzard nests is somewhat unusual.
Species such as the black kite ("Milvus migrans"), booted eagle ("Hieraeetus pennatus") and the lesser spotted eagle have been known to displace actively nesting buzzards, although in some cases the buzzards may attempt to defend themselves. The broad range of accipitrids that take over buzzard nests is somewhat unusual. Even with birds not traditionally considered raptorial, such as common ravens, may compete for nesting sites with buzzards. In urban vicinities of southwestern England, it was found that peregrine falcons ("Falco peregrinus") were harassing buzzards so persistently, in many cases resulting in injury or death for the buzzards, the attacks tending to peak during the falcon's breeding seasons and tend to be focused on subadult buzzards. Despite often being dominated in nesting site confrontations by even similarly sized raptors, buzzards appear to be bolder in direct competition over food with other raptors outside of the context of breeding, and has even been known to displace larger birds of prey such as red kites ("Milvus milvus") and female buzzards may also dominate male goshawks (which are much smaller than the female goshawk) at disputed kills.
Common buzzards are occasionally threatened by predation by other raptorial birds. Northern goshawks have been known to have preyed upon buzzards in a few cases. Much larger raptors are known to have killed a few buzzards as well, including steppe eagles ("Aquila nipalensis") on migrating steppe buzzards in Israel. Further instances of predation on buzzards have involved golden, eastern imperial ("Aquila heliaca"), Bonelli's ("Aquila fasciata") and white-tailed eagles ("Haliaeetus albicilla") in Europe. Besides preying on adult buzzard, white-tailed eagles have been known to raise buzzards with their own young. These are most likely cases of eagles carrying off young buzzard nestlings with the intention of predation but, for unclear reasons, not killing them. Instead the mother eagle comes to brood the young buzzard. Despite the difference of the two species diets, white-tailed eagles are surprisingly successful at raising young buzzards (which are conspicuously much smaller than their own nestlings) to fledging.
Despite the difference of the two species diets, white-tailed eagles are surprisingly successful at raising young buzzards (which are conspicuously much smaller than their own nestlings) to fledging. Studies in Lithuania of white-tailed eagle diets found that predation on common buzzards was more frequent than anticipated, with 36 buzzard remains found in 11 years of study of the summer diet of the white-tailed eagles. While nestling buzzards were multiple times more vulnerable to predation than adult buzzards in the Lithuanian data, the region's buzzards expelled considerable time and energy during the late nesting period trying to protect their nests. The most serious predator of common buzzards, however, is almost certainly the Eurasian eagle-owl ("Bubo bubo"). This is a very large owl with a mean body mass about three to four times greater than that of a buzzard. The eagle-owl, despite often taking small mammals that broadly overlap with those selected by buzzards, is considered a "super-predator" that is a major threat to nearly all co-existing raptorial birds, capably destroying whole broods of other raptorial birds and dispatching adult raptors even as large as eagles.
The eagle-owl, despite often taking small mammals that broadly overlap with those selected by buzzards, is considered a "super-predator" that is a major threat to nearly all co-existing raptorial birds, capably destroying whole broods of other raptorial birds and dispatching adult raptors even as large as eagles. Due to their large numbers in edge habitats, common buzzards frequently feature heavily in the eagle-owl's diet. Eagle-owls, as will some other large owls, also readily expropriate the nests of buzzards. In the Czech Republic and in Luxembourg, the buzzard was the third and fifth most frequent prey species for eagle-owls, respectively. The reintroduction of eagle-owls to sections of Germany has been found to have a slight deleterious effect on the local occupancy of common buzzards. The only sparing factor is the temporal difference (the buzzard nesting later in the year than the eagle-owl) and buzzards may locally be able to avoid nesting near an active eagle-owl family.
The only sparing factor is the temporal difference (the buzzard nesting later in the year than the eagle-owl) and buzzards may locally be able to avoid nesting near an active eagle-owl family. Despite not being known predators of buzzards, other large, vole-eating owls are known to displace or to be avoided by nesting buzzards, such as great grey owls ("Strix nebulosa") and Ural owls ("Strix uralensis"). Unlike with large birds of prey, next to nothing is known of mammalian predators of common buzzards, despite up to several nestlings and fledglings being likely depredated by mammals. Common buzzards themselves rarely present a threat to other raptorial birds but may occasionally kill a few of those of smaller size. The buzzard is a known predator of Eurasian sparrowhawks ("Accipiter nisus"), common kestrel and lesser kestrel ("Falco naumanni") . Perhaps surprisingly, given the nocturnal habits of this prey, the group of raptorial birds the buzzard is known to hunt most extensively is owls. Known owl prey has included Western barn owls ("Tyto alba"), European scops owls ("Otus scops"), tawny owls ("Strix aluco"), little owls ("Athene noctua"), boreal owls ("Aegolius funereus"), long-eared owls ("Asio otus") and short-eared owls ("Asio flammeus"). Despite their relatively large size, tawny owls are known to avoid buzzards as there are several records of them preying upon the owls.
Breeding. Nesting territories and density. Home ranges of common buzzards are generally . The size of breeding territory seem to be generally correlated with food supply. In a German study, the range was with an average of . Some of the lowest pair densities of common buzzards seem to come from Russia. For instance, in Kerzhenets Nature Reserve, the recorded density was 0.6 pairs per and the average distance of nearest neighbors was . The Snowdonia region of northern Wales held a pair per with a mean nearest neighbor distance of ; in adjacent Migneint, pair occurrence was , with a mean distance of . In the Teno massif of the Canary Islands, the average density was estimated as 23 pairs per , similar to that of a middling continental population. On another set of islands, on Crete the density of pairs was lower at 5.7 pairs per ; here buzzards tend to have an irregular distribution, some in lower intensity harvest olive groves but their occurrence actually more common in agricultural than natural areas. In the Italian Alps, it was recorded in 1993–96 that there were from 28 to 30 pairs per . In central Italy, density average was lower at 19.74 pairs per . Higher density areas are known than those above.
In the Italian Alps, it was recorded in 1993–96 that there were from 28 to 30 pairs per . In central Italy, density average was lower at 19.74 pairs per . Higher density areas are known than those above. Two areas of the Midlands of England showed occupancies of 81 and 22 territorial pairs per . High buzzard densities there were associated with high proportions of unimproved pasture and mature woodland within the estimated territories. Similarly high densities of common buzzards were estimated in central Slovakia using two different methods, here indicating densities of 96 to 129 pairs per . Despite claims from the study of the English midlands were the highest known territory density for the species, a number ranging from 32 to 51 pairs in wooded area of merely in Czech Republic seems to surely exceed even those densities. The Czech study hypothesized that fragmentation of forest in human management of lands for wild sheep and deer, creating exceptional concentrations of prey such as voles, and lack of appropriate habitat in surrounding regions for the exceptionally high density.
In the North-Estonian Neeruti landscape reserve (area 1250 ha), Marek Vahula found 9 populated nests in 1989 and 1990. One nest was found in 1982 and is apparently the oldest known nest that is still populated today. Common buzzards maintain their territories through flight displays. In Europe, territorial behaviour generally starts in February. However, displays are not uncommon throughout year in resident pairs, especially by males, and can elicit similar displays by neighbors. In them, common buzzards generally engage in high circling, spiraling upward on slightly raised wings. Mutual high circling by pairs sometimes go on at length, especially during the period prior to or during breeding season. In mutual displays, a pair may follow each other at in level flight. During the mutual displays, the male may engage in exaggerated deep flapping or zig-zag tumbling, apparently in response to the female being too distant. Two or three pairs may circle together at times and as many as 14 individual adults have been recorded over established display sites.
Two or three pairs may circle together at times and as many as 14 individual adults have been recorded over established display sites. Sky-dancing by common buzzards have been recorded in spring and autumn, typically by male but sometimes by female, nearly always with much calling. Their sky-dances are of the rollercoaster type, with upward sweep until they start to stall, but sometimes embellished with loops or rolls at the top. Next in the sky-dance, they dive on more or less closed wings before spreading them and shooting up again, upward sweeps of up to , with dive drops of up to at least . These dances may be repeated in series of 10 to 20. In the climax of the sky dance, the undulations become progressive shallower, often slowing and terminating directly onto a perch. Various other aerial displays include low contour flight or weaving among trees, frequently with deep beats and exaggerated upstrokes which show underwing pattern to rivals perched below. Talon grappling and occasionally cartwheeling downward with feet interlocked has been recorded in buzzards and, as in many raptors, is likely the physical culmination of the aggressive territorial display, especially between males.
Talon grappling and occasionally cartwheeling downward with feet interlocked has been recorded in buzzards and, as in many raptors, is likely the physical culmination of the aggressive territorial display, especially between males. Despite the highly territorial nature of buzzards and their devotion to a single mate and breeding ground each summer, there is one case of a polyandrous trio of buzzards nesting in the Canary Islands. Nests. Common buzzards tend to build a bulky nest of sticks, twigs and often heather. Commonly, nests are up to across and deep. With reuse over years, the diameter can reach or exceed and weight of nests can reach over . Active nests tend to be lined with greenery, most often this consists of broad-leafed foliage but sometimes also includes rush or seaweed locally. Nest height in trees is commonly , usually by main trunk or main crutch of the tree. In Germany, trees used for nesting consisted mostly of red beeches ("Fagus sylvatica") (in 337 cases), whereas a further 84 were in assorted oaks.
In Germany, trees used for nesting consisted mostly of red beeches ("Fagus sylvatica") (in 337 cases), whereas a further 84 were in assorted oaks. Buzzards were recorded to nest almost exclusively in pines in Spain at a mean height of . Trees are generally used for a nesting location but they will also utilize crags or bluffs if trees are unavailable. Buzzards in one English study were surprisingly partial to nesting on well-vegetated banks and due to the rich surrounding environment habitat and prey population, were actually more productive than nests located in other locations here. Furthermore, a few ground nests were recorded in high prey-level agricultural areas in the Netherlands. In the Italian Alps, 81% of 108 nests were on cliffs. The common buzzard generally lacks the propensity of its Nearctic counterpart, the red-tailed hawk, to occasionally nest on or near manmade structures (often in heavily urbanized areas) but in Spain some pairs recorded nesting along the perimeter of abandoned buildings. Pairs often have several nests but some pairs may use one over several consecutive years.
The common buzzard generally lacks the propensity of its Nearctic counterpart, the red-tailed hawk, to occasionally nest on or near manmade structures (often in heavily urbanized areas) but in Spain some pairs recorded nesting along the perimeter of abandoned buildings. Pairs often have several nests but some pairs may use one over several consecutive years. Two to four alternate nests in a territory is typical for common buzzards, especially those breeding further north in their range. Reproduction and eggs. The breeding season commences at differing times based on latitude. Common buzzard breeding seasons may fall as early as January to April but typically the breeding season is March to July in much of Palearctic. In the northern stretches of the range the breeding season may last into May–August. Mating usually occurs on or near the nest and lasts about 15 seconds, typically occurring several times a day. Eggs are usually laid in 2 to 3-day intervals. The clutch size can range from to 2 to 6, a relatively large clutch for an accipitrid.
Eggs are usually laid in 2 to 3-day intervals. The clutch size can range from to 2 to 6, a relatively large clutch for an accipitrid. More northerly and westerly buzzard usually bear larger clutches, which average nearer 3, than those further east and south. In Spain, the average clutch size is about 2 to 2.3. From 4 locations in different parts of Europe, 43% had clutch size of 2, 41% had size of 3, clutches of 1 and 4 each constituted about 8%. Laying dates are remarkably constant throughout Great Britain. There are, however, highly significant differences in clutch size between British study areas. These do not follow any latitudinal gradient and it is likely that local factors such as habitat and prey availability are more important determinants of clutch size. The eggs are white in ground colour, rather round in shape with sporadic red to brown markings sometimes lightly showing. In the nominate race, egg size is in height by in diameter with an average of in 600 eggs. In the race of "vulpinus", egg height is by with an average of in 303 eggs.
In the nominate race, egg size is in height by in diameter with an average of in 600 eggs. In the race of "vulpinus", egg height is by with an average of in 303 eggs. Eggs are generally laid in late March to early April in extreme south, sometime in April in most of Europe, into May and possibly even early June in the extreme north. If eggs are lost to a predator (including humans) or fail in some other way, common buzzards do not usually lay replacement clutches but they have been recorded, even with 3 attempts of clutches by a single female. The female does most but not all of the incubating, doing so for a total of 33–35 days. The female remains at the nest brooding the young in the early stages with the male bringing all prey. At about 8–12 days, both the male and female will bring prey but the female continues to do all feeding until the young can tear up their own prey.
Development of young. Once hatching commences, it may take 48 hours for the chick to chip out. Hatching may take place over 3–7 days, with new hatchlings averaging about in body mass. Often the youngest nestling dies from starvation, especially in broods of three or more. In nestlings, the first down replaces by longer, coarser down at about 7 days of age with the first proper feathers appearing at 12 to 15 days. The young are nearly fully feathered rather than downy at about a month of age and can start to feed themselves as well. The first attempts to leave the nest are often at about 40–50 days, averaging usually 40–45 in nominate buzzards in Europe, but more quickly on average at 40–42 in "vulpinus". Fledging occurs typically at 43–54 days but in extreme cases at as late 62 days. Sexual dimorphism is apparent in European fledglings, as females often scale about against in males. After leaving the nest, buzzards generally stay close by, but with migratory ones there is more definitive movement generally southbound.
After leaving the nest, buzzards generally stay close by, but with migratory ones there is more definitive movement generally southbound. Full independence is generally sought 6 to 8 weeks after fledging. 1st year birds generally remain in wintering area for following summer but then return to near area of origin but then migrate south again without breeding. Radio-tracking suggests that most dispersal, even relatively early dispersals, by juvenile buzzards is undertaken independently rather than via exile by parents, as has been recorded in some other birds of prey. In common buzzards, generally speaking, siblings stay quite close to each other after dispersal from their parents and form something of a social group, although parents usually tolerate their presence on their territory until they are laying another clutch. However, the social group of siblings disbands at about a year of age.
Breeding success rates. Numerous factors may weigh into the breeding success of common buzzards. Chiefly among these are prey populations, habitat, disturbance and persecution levels and innerspecies competition. In Germany, intra- and interspecific competition, plumage morph, laying date, precipitation levels and anthropogenic disturbances in the breeding territory, in declining order, were deemed to be the most significant bearers of breeding success. In an accompanying study, it was found that a mere 17% of adult birds of both sexes present in a German study area produced 50% of offspring, so breeding success may be lower than perceived and many adult buzzards for unknown causes may not attempt to breed at all. High breeding success was detected in Argyll, Scotland, due likely to hearty prey populations (rabbits) but also probably a lower local rate of persecution than elsewhere in the British isles. Here, the mean number of fledglings were 1.75 against 0.82–1.41 in other parts of Britain. It was found in the English Midlands that breeding success both by measure of clutch size and mean number of fledglings, was relatively high thanks again to high prey populations.
It was found in the English Midlands that breeding success both by measure of clutch size and mean number of fledglings, was relatively high thanks again to high prey populations. Breeding success was lower farther from significant stands of trees in the Midlands and most nesting failures that could be determined occurred in the incubation stage, possibly in correlation with predation of eggs by corvids. More significant than even prey, late winter-early spring was found to be likely the primary driver of breeding success in buzzards from southern Norway. Here, even in peak vole years, nesting success could be considerably hampered by heavy snow at this crucial stage. In Norway, large clutches of 3+ were expected only in years with minimal snow cover, high vole populations and lighter rains in May–June. In the Italian Alps, the mean number of fledglings per pair was 1.07. 33.4% of nesting attempts were failures per a study in southwestern Germany, with an average of 1.06 of all nesting attempts and 1.61 for all successful attempt.
In the Italian Alps, the mean number of fledglings per pair was 1.07. 33.4% of nesting attempts were failures per a study in southwestern Germany, with an average of 1.06 of all nesting attempts and 1.61 for all successful attempt. In Germany, weather conditions and rodent populations seemed to be the primary drivers of nesting success. In Murcia part of Spain contrasted with Biscay to the north, higher levels of interspecific competition from booted eagles and northern goshawks did not appear to negatively affect breeding success due to more ample prey populations (rabbits again) in Murcia than in Biscay. In the Westphalia area of Germany, it was found that intermediate colour morphs were more productive than those that were darker or lighter. For reasons that are not entirely clear, apparently fewer parasites were found to afflict broods of intermediate plumaged buzzard less so than dark and light phenotypes, in particular higher melanin levels somehow were found to be more inviting to parasitic organism that effect the health of the buzzard's offspring.
For reasons that are not entirely clear, apparently fewer parasites were found to afflict broods of intermediate plumaged buzzard less so than dark and light phenotypes, in particular higher melanin levels somehow were found to be more inviting to parasitic organism that effect the health of the buzzard's offspring. The composition of habitat and its relation to human disturbance were important variables for the dark and light phenotypes but were less important to intermediate individuals. Thus selection pressures resulting from different factors did not vary much between sexes but varied between the three phenotypes in the population. Breeding success in areas with wild European rabbits was considerably effected by rabbit myxomatosis and rabbit haemorrhagic disease, both of which have heavily depleted wild rabbit population. Breeding success in formerly rabbit-rich areas were recorded to decrease from as much as 2.6 to as little as 0.9 young per pair.
Breeding success in formerly rabbit-rich areas were recorded to decrease from as much as 2.6 to as little as 0.9 young per pair. The mean life expectancy was estimated at 6.3 years in the late 1950s, but this was at a time of high persecution when humans were causing 50–80% of buzzard deaths. In a more modern context with regionally reduced persecution rates, the lifespan expected can be higher (possibly in excess of 10 years at times) but is still widely variable due to a wide variety of factors. Status. The common buzzard is one of the most numerous birds of prey in its range. Almost certainly, it is the most numerous diurnal bird of prey throughout Europe. Conservative estimates put the total population at no fewer than 700,000 pairs in Europe, which are more than twice the total estimates for the next four birds of prey estimated as most common: the Eurasian sparrowhawk (more than 340,000 pairs), the common kestrel (more than 330,000 pairs) and the northern goshawk (more than 160,000 pairs). Ferguson-Lees et al.
Conservative estimates put the total population at no fewer than 700,000 pairs in Europe, which are more than twice the total estimates for the next four birds of prey estimated as most common: the Eurasian sparrowhawk (more than 340,000 pairs), the common kestrel (more than 330,000 pairs) and the northern goshawk (more than 160,000 pairs). Ferguson-Lees et al. roughly estimated that the total population of the common buzzard ranges to nearly 5 million pairs but at time was including the now split-off species of eastern and Himalayan buzzards in those numbers. These numbers may be excessive but the total population of common buzzards is certain to total well over seven figures. More recently, the IUCN estimated the common buzzard (sans the Himalayan and eastern subspecies) to number somewhere between 2.1 and 3.7 million birds, which would put this buzzard one of the most numerous of all accipitrid family members (estimates for Eurasian sparrowhawks, red-tailed hawks and northern goshawks also may range over 2 million). In 1991, other than their absence in Iceland, after having been extent as breeder by 1910, buzzards recolonized Ireland sometime in the 1950s and has increased by the 1990s to 26 pairs.
after having been extent as breeder by 1910, buzzards recolonized Ireland sometime in the 1950s and has increased by the 1990s to 26 pairs. Supplemental feeding has reportedly helped the Irish buzzard population to rebound, especially where rabbits have decreased. Most other countries have at least four figures of breeding pairs. As of the 1990s, other countries such as Great Britain, France, Switzerland, Czech Republic, Poland, Sweden, Belarus and Ukraine all numbered pairs well into five figures, while Germany had an estimated 140,000 pairs and European Russian may have held 500,000 pairs. Between 44,000 and 61,000 pairs nested in Great Britain by 2001 with numbers gradually increasing after past persecution, habitat alteration and prey reductions, making it by far the most abundant diurnal raptor there. In Westphalia, Germany, population of buzzards was shown to nearly triple over the last few decades. The Westphalian buzzards are possibly benefiting from increasingly warmer mean climate, which in turn is increasing vulnerability of voles. The Westphalian buzzards are possibly benefiting from increasingly warmer mean climate, which in turn is increasing vulnerability of voles. However, the rate of increase was significantly greater in males than in females, in part because of reintroduced Eurasian eagle-owls to the region preying on nests (including the brooding mother), which may in turn put undue pressure on the local buzzard population.
At least 238 common buzzards killed through persecution were recovered in England from 1975 to 1989, largely through poisoning. Persecution did not significantly differ at any time due this span of years nor did the persecution rates decrease, nor did it when compared to rates of last survey of this in 1981. While some persecution persists in England, it is probably slightly less common today. The buzzard was found to be the most vulnerable raptor to power-line collision fatalities in Spain probably as it is one of the most common largish birds, and together with the common raven, it accounted for nearly a third of recorded electrocutions. Given its relative abundance, the common buzzard is held as an ideal bioindicator, as they are effected by a range of pesticide and metal contamination through pollution like other raptors but are largely resilient to these at the population levels. In turn, this allows biologists to study (and harvest if needed) the buzzards intensively and their environments without affecting their overall population. The lack of affect may be due to the buzzard's adaptability as well as its relatively short, terrestrially-based food chain, which exposes them to less risk of contamination and population depletions than raptors that prey more heavily on water-based prey (such as some large eagles) or other birds (such as falcons). Common buzzards are seldom vulnerable to egg-shell thinning from DDT as are other raptors but egg-shell thinning has been recorded. Other factors that negatively effect raptors have been studied in common buzzards are helminths, avipoxvirus and assorted other viruses.
Bohrium Bohrium is a synthetic chemical element; it has symbol Bh and atomic number 107. It is named after Danish physicist Niels Bohr. As a synthetic element, it can be created in particle accelerators but is not found in nature. All known isotopes of bohrium are highly radioactive; the most stable known isotope is 270Bh with a half-life of approximately 2.4 minutes, though the unconfirmed 278Bh may have a longer half-life of about 11.5 minutes. In the periodic table, it is a d-block transactinide element. It is a member of the 7th period and belongs to the group 7 elements as the fifth member of the 6d series of transition metals. Chemistry experiments have confirmed that bohrium behaves as the heavier homologue to rhenium in group 7. The chemical properties of bohrium are characterized only partly, but they compare well with the chemistry of the other group 7 elements. History. Discovery. Two groups claimed discovery of the element. Evidence of bohrium was first reported in 1976 by a Soviet research team led by Yuri Oganessian, in which targets of bismuth-209 and lead-208 were bombarded with accelerated nuclei of chromium-54 and manganese-55, respectively. Two activities, one with a half-life of one to two milliseconds, and the other with an approximately five-second half-life, were seen. Since the ratio of the intensities of these two activities was constant throughout the experiment, it was proposed that the first was from the isotope bohrium-261 and that the second was from its daughter dubnium-257. Later, the dubnium isotope was corrected to dubnium-258, which indeed has a five-second half-life (dubnium-257 has a one-second half-life); however, the half-life observed for its parent is much shorter than the half-lives later observed in the definitive discovery of bohrium at Darmstadt in 1981. The IUPAC/IUPAP Transfermium Working Group (TWG) concluded that while dubnium-258 was probably seen in this experiment, the evidence for the production of its parent bohrium-262 was not convincing enough.
In 1981, a German research team led by Peter Armbruster and Gottfried Münzenberg at the GSI Helmholtz Centre for Heavy Ion Research (GSI Helmholtzzentrum für Schwerionenforschung) in Darmstadt bombarded a target of bismuth-209 with accelerated nuclei of chromium-54 to produce 5 atoms of the isotope bohrium-262: This discovery was further substantiated by their detailed measurements of the alpha decay chain of the produced bohrium atoms to previously known isotopes of fermium and californium. The IUPAC/IUPAP Transfermium Working Group (TWG) recognised the GSI collaboration as official discoverers in their 1992 report. Proposed names. In September 1992, the German group suggested the name "nielsbohrium" with symbol "Ns" to honor the Danish physicist Niels Bohr. The Soviet scientists at the Joint Institute for Nuclear Research in Dubna, Russia had suggested this name be given to element 105 (which was finally called dubnium) and the German team wished to recognise both Bohr and the fact that the Dubna team had been the first to propose the cold fusion reaction, and simultaneously help to solve the controversial problem of the naming of element 105. The Dubna team agreed with the German group's naming proposal for element 107.
There was an element naming controversy as to what the elements from 104 to 106 were to be called; the IUPAC adopted "unnilseptium" (symbol "Uns") as a temporary, systematic element name for this element. In 1994 a committee of IUPAC recommended that element 107 be named "bohrium", not "nielsbohrium", since there was no precedent for using a scientist's complete name in the naming of an element. This was opposed by the discoverers as there was some concern that the name might be confused with boron and in particular the distinguishing of the names of their respective oxyanions, "bohrate" and "borate". The matter was handed to the Danish branch of IUPAC which, despite this, voted in favour of the name "bohrium", and thus the name "bohrium" for element 107 was recognized internationally in 1997; the names of the respective oxyanions of boron and bohrium remain unchanged despite their homophony. Isotopes. Bohrium has no stable or naturally occurring isotopes. Several radioactive isotopes have been synthesized in the laboratory, either by fusing two atoms or by observing the decay of heavier elements. Twelve different isotopes of bohrium have been reported with atomic masses 260–262, 264–267, 270–272, 274, and 278, one of which, bohrium-262, has a known metastable state. All of these but the unconfirmed 278Bh decay only through alpha decay, although some unknown bohrium isotopes are predicted to undergo spontaneous fission.
The lighter isotopes usually have shorter half-lives; half-lives of under 100 ms for 260Bh, 261Bh, 262Bh, and 262mBh were observed. 264Bh, 265Bh, 266Bh, and 271Bh are more stable at around 1 s, and 267Bh and 272Bh have half-lives of about 10 s. The heaviest isotopes are the most stable, with 270Bh and 274Bh having measured half-lives of about 2.4 min and 40 s respectively, and the even heavier unconfirmed isotope 278Bh appearing to have an even longer half-life of about 11.5 minutes. The most proton-rich isotopes with masses 260, 261, and 262 were directly produced by cold fusion, those with mass 262 and 264 were reported in the decay chains of meitnerium and roentgenium, while the neutron-rich isotopes with masses 265, 266, 267 were created in irradiations of actinide targets. The five most neutron-rich ones with masses 270, 271, 272, 274, and 278 (unconfirmed) appear in the decay chains of 282Nh, 287Mc, 288Mc, 294Ts, and 290Fl respectively. The half-lives of bohrium isotopes range from about ten milliseconds for 262mBh to about one minute for 270Bh and 274Bh, extending to about 11.5 minutes for the unconfirmed 278Bh, which may have one of the longest half-lives among reported superheavy nuclides.
Predicted properties. Very few properties of bohrium or its compounds have been measured; this is due to its extremely limited and expensive production and the fact that bohrium (and its parents) decays very quickly. A few singular chemistry-related properties have been measured, but properties of bohrium metal remain unknown and only predictions are available. Chemical. Bohrium is the fifth member of the 6d series of transition metals and the heaviest member of group 7 in the periodic table, below manganese, technetium and rhenium. All the members of the group readily portray their group oxidation state of +7 and the state becomes more stable as the group is descended. Thus bohrium is expected to form a stable +7 state. Technetium also shows a stable +4 state whilst rhenium exhibits stable +4 and +3 states. Bohrium may therefore show these lower states as well. The higher +7 oxidation state is more likely to exist in oxyanions, such as perbohrate, , analogous to the lighter permanganate, pertechnetate, and perrhenate. Nevertheless, bohrium(VII) is likely to be unstable in aqueous solution, and would probably be easily reduced to the more stable bohrium(IV).

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