Update README.md

README.md

@@ -103,17 +103,32 @@ Pied avocet predictions are **not part of the main leaderboard** and will not af
 
 \* Pied avocet is an additional optional target species — see the section above. Pied avocet predictions contribute only to the secondary generalist leaderboard.
 
-Each row tells participants the **target species** that needs an integer count for that aviary. Each aviary also contains additional non-target species; the per-aviary non-target composition is held private until the challenge concludes.
+Each row tells participants the **target species** that needs an integer count for that aviary. Each aviary also contains additional non-target species; the **complete per-aviary composition and ground-truth counts** for every evaluation aviary are provided in [`metadata/eval_ground_truth.csv`](metadata/eval_ground_truth.csv), released after the challenge concluded.
 
-### Species inventory (combined, no per-aviary breakdown)
+### Species inventory
 
-Some evaluation aviaries are continuations of development-set aviaries (recorded on different days). Publishing the full per-aviary species composition for the evaluation set would therefore reveal which evaluation aviaries correspond to which development aviaries, compromising the held-out nature of the data.
+The full per-aviary ground truth — every species and its individual count in each evaluation aviary — is available in [`metadata/eval_ground_truth.csv`](metadata/eval_ground_truth.csv), released after the challenge concluded. During the challenge only the combined list below was published, so that the per-aviary composition (and the correspondence between some evaluation and development aviaries) stayed held-out.
 
-Instead, we publish a single combined species inventory listing every species that appears *somewhere* in the evaluation set, without specifying which aviary each species belongs to:
+A combined inventory of every species appearing *somewhere* in the evaluation set is also provided in [`metadata/eval_species_list.csv`](metadata/eval_species_list.csv) — **67 species total**: 3 main target species, 1 optional target species, and 63 non-target species. **No species outside this list appears anywhere in the evaluation audio**, so it is the safe and tight superset to use when running pre-trained detectors with a species-filter list. The per-aviary `target_species` column in `eval_recording_info.csv` tells participants which species needs to be counted for each aviary.
 
-[`metadata/eval_species_list.csv`](metadata/eval_species_list.csv) — **67 species total**: 3 main target species, 1 optional target species, and 63 non-target species.
+### Evaluation-set structure: continuation and repeated-session aviaries
 
-Participants are guaranteed that **no species outside this list appears anywhere in the evaluation audio**. The inventory is therefore the safe and tight superset to use when running pre-trained detectors with a species-filter list. The per-aviary `target_species` column in `eval_recording_info.csv` (and in the table above) tells participants which species needs to be counted for each aviary; the remaining per-aviary species composition stays private until challenge results are published.
+The following notes document the structure of the evaluation set. Not every evaluation aviary is an independent, newly recorded environment, and this matters when interpreting per-species results.
+
+**Red-billed quelea — held-out days of development aviaries.** The two quelea evaluation aviaries are *not* new environments. They use the **remaining, previously unreleased days from the same continuous recording sessions** as the corresponding development aviaries:
+
+| Eval aviary | Continues | Target population | What differs |
+|---|---|---|---|
+| `eval_aviary_1` | `dev_aviary_1` | Red-billed quelea (153) | Recording days only |
+| `eval_aviary_2` | `dev_aviary_3` | Red-billed quelea (61) | Recording days only |
+
+The aviary, recording setup, and bird population are identical to the matching development aviary — only the recording days differ. For quelea, evaluation therefore measures generalization **across unseen days of the same recording**, not across a new environment, which is why the target counts equal the development values.
+
+**Hadada ibis — one environment recorded twice.** `eval_aviary_6` and `eval_aviary_7` are the **same physical aviary and the same bird population**, captured in two separate recording sessions (different dates/times and recording setup). Both therefore have the same Hadada ibis count (4), and they should be read as two correlated recordings of a single environment rather than two independent test cases — the same situation described for `dev_aviary_5` and `dev_aviary_6` in the development set. This environment is new relative to the development set.
+
+**Greater flamingo and Pied avocet — new, independent environments.** The two Greater flamingo aviaries (`eval_aviary_4`, `eval_aviary_8`) and the four optional Pied avocet aviaries are newly recorded environments with no development-set counterpart. The flamingo aviaries were deliberately selected to fall **outside the development population range** (11 and 195 individuals, versus 52–161 in development), so they test extrapolation to unseen colony sizes in addition to a new acoustic environment.
+
+**Why this matters.** The meaning of "generalization" is not uniform across the target species: quelea is the same environment across unseen days, Hadada ibis is a single environment recorded twice, and Greater flamingo (and Pied avocet) require genuine cross-aviary generalization — with the flamingo aviaries additionally probing out-of-range population sizes. Aggregate scores should be interpreted with this structure in mind, and the two Hadada ibis aviaries (and the paired quelea recordings) are not statistically independent.
 
 ---
 
@@ -149,6 +164,7 @@ BioDCASE2026_Bird_Counting/
 └── metadata/
     ├── ground_truth.csv             # development set ground truth
     ├── recording_info.csv           # development set summary
+    ├── eval_ground_truth.csv        # evaluation set ground truth (per-aviary, all species)
     ├── eval_recording_info.csv      # evaluation set summary + target species per aviary
     └── eval_species_list.csv        # evaluation set combined species inventory (67 species)
 ```
@@ -195,6 +211,18 @@ Summary statistics per development aviary:
 | `n_days` | Number of recording days included |
 | `n_files` | Total number of audio files |
 
+### `metadata/eval_ground_truth.csv` (evaluation set)
+
+Complete species inventory and ground-truth counts for all 10 evaluation aviaries, including both target and non-target species. Released after the challenge concluded; same format as the development-set `ground_truth.csv`, with an extended `is_target` column that distinguishes the optional target:
+
+| Column | Description |
+|---|---|
+| `aviary_id` | Aviary identifier (`eval_aviary_1` through `eval_aviary_10`) |
+| `common_name` | English common name of the species |
+| `scientific_name` | Binomial scientific name |
+| `count` | Number of individuals present in the aviary |
+| `is_target` | `0` = non-target, `1` = main-leaderboard target (Greater flamingo, Red-billed quelea, Hadada ibis), `2` = optional target (Pied avocet) |
+
 ### `metadata/eval_recording_info.csv` (evaluation set)
 
 Per-aviary summary for the evaluation set, including the target species each aviary should be scored on: