Geographic variation in song structure in the Hermit Thrush (<i>Catharus guttatus</i>)
Bibliographic record
Abstract
Although the Hermit Thrush (Catharus guttatus) exhibits distinctive morphological and genetic differences across its breeding range (Alvarado et al. 2014), comparatively little is known about geographic variation in song structure and whether song variation corresponds with those morphological and genetic differences. To address this, we collected recordings from throughout the species' breeding range and assessed frequency and temporal characteristics of song structure. Eastern and western birds differed dramatically with respect to song structure, most notably with respect to introductory note frequencies: eastern birds exhibited a larger range of introductory note frequencies than western birds. They also differed with respect to temporal characteristics: western birds sang longer introductory notes, but shorter post-introductory portions, than eastern birds. Numerous differences in structure were also detected within each lineage. For example, within the western lineage, introductory note frequencies were much higher in the Western Lowland group that occupies the Pacific coast compared to the inland Western Mountain group. There were also some differences seen within those groups; for example, in the western Canadian subspecies C. g. euborius recordings from high altitudes (>1900 m in the Canadian Rockies) were structurally distinct from those recorded at lower altitudes. Highlighting the distinctive geographic differences in song structure, a discriminant function analysis using song structure characteristics classified recordings into their geographic groups with 97.0% accuracy. This array of geographic song differences, taking place at multiple levels, suggests that Hermit Thrush song has been shaped by a variety of forces, ranging from large-scale geological events to factors such as habitat differences and cultural drift that operate on a smaller geographic scale (i.e. within subspecies).
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".