{
  "frozen_utc": "2026-09-19T04:17:39.461839+00:00",
  "id": "019",
  "title": "Independent focal-recording extension of the bird mixture experiment",
  "status": "Frozen source extension before audio outcomes",
  "question": "Does the disjoint-time detection loss reproduce with adequate species coverage in separately sourced focal recordings?",
  "rationale": "The entry018 held-out effect replicated but its eight-species diversity gate failed. A separately specified source dataset can test transfer beyond the four eligible soundscape species without relaxing the score or loss thresholds. This is an extension of the same hypothesis, not an unrelated discovery.",
  "minimal_test": "Use the pinned CEB train_xenocanto recordings, independently annotated from the soundscape test recordings. For every target event, require all annotations intersecting a centered 1.2-second passage to be the target species, including blocking unknown-species annotations. Exclude passages starting before zero or extending beyond the actual recording. Before model outcomes, retain at most12 distinct-recording candidates/species and360 candidates total using SHA256 rank 019:20260919:event_id. Require target >=0.5 at both positions. Keep up to4 eligible clips/species with at least3 distinct files and at most16 species by fixed hash. Minimal eligibility gate: >=8 species,>=24 clips. Mixture effect gate unchanged: >=20% losses in nonoverlap at0.5,>=4 species affected in>=2 independent recording pairs. No further selection expansion after outcomes.",
  "novelty": "Entry018 first novelty review applies to the same narrow claim; additional literature review required after this source extension. Synthetic mixing, source separation and environmental interference are known.",
  "decision": "Acquire source archive, verify checksum, run eligibility, then mixture validation if eligible. Full study also requires matched preprocessing controls and exact ecological-presence enumeration.",
  "limitations": "Focal Xeno-Canto clips may have appeared in BirdNET training; this is not an unseen-classification-accuracy benchmark. The manipulated counterfactual remains defined, but ecological prevalence and field interaction claims are excluded. Recordists and per-file licenses must be retained.",
  "sources": [
    {
      "title": "CEB pinned dataset",
      "url": "https://doi.org/10.5281/zenodo.21821133"
    },
    {
      "title": "BirdNET v2.4 model source",
      "url": "https://github.com/birdnet-team/BirdNET-Analyzer/tree/v1.5.1"
    }
  ],
  "searches": []
}