Burning the candle at both ends: two sympatric thrushes are equally detectable and sing at similar rates at dawn and dusk
Bibliographic record
Abstract
Abstract Many birds sing prolifically during the dawn chorus and a subset of these species also sing at dusk. How vocal activity varies between these two periods has not been examined in many species. In this study, we explored rates of detection and song rate of two sympatric passerines, hermit thrushes ( Catharus guttatus ) and Swainson’s thrushes ( Catharus ustulatus ), at dawn and dusk. At three intervals in the breeding season, we examined eight 1-min intervals from 60 min before to 60 min after both sunrise and sunset. We recorded whether each species was detected, the total number of songs sung, and the number of individuals singing. We found that both hermit and Swainson’s thrushes were equally likely to be detected at all time periods except that hermit thrush singing was reduced and Swainson’s thrush song was absent 60 min after sunset. We also detected both species singing less often earlier in the season. We found that song rate was not strongly related to either time of day or time of season, but the song rate/individual detected was higher for hermit thrush when more individuals were singing. Our results suggest that the dusk chorus ceases at a higher light level than the dawn chorus starts and that neighbors’ singing may increase the song rate. Our study adds to our general understanding of the daily and seasonal singing phenology of hermit and Swainson’s thrushes and suggests breeding bird surveys for these two species could occur in both morning and evening with equal likelihood of detection.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".