Genetics, morphology, and ecological niche modeling do not support the subspecies status of the endangered Southwestern Willow Flycatcher (<i>Empidonax traillii extimus</i>)
Bibliographic record
Abstract
ABSTRACT The Willow Flycatcher (Empidonax traillii) breeds throughout much of the United States, northwestern Mexico, and southeastern and southwestern Canada. A subspecies found in the southwestern United States and northwestern Mexico, E. t. extimus (Southwestern Willow Flycatcher), is listed as endangered under the U.S. Endangered Species Act (ESA). This subspecies was described in 1948, based on comparisons of a few external morphological characters from an unstated number of specimens and localities, although it was excluded from the last official list of subspecies by the American Ornithologists' Union. Like most avian subspecies, its validity has not been tested with modern morphological or genetic methods. Recent assessments of the subspecies have assumed it to be a distinct taxon, and some authors have limited their comparisons to E. t. extimus versus E. t. adastus (the subspecies immediately to the north of E. t. extimus), excluding comparison to western (E. t. brewsteri) and eastern (E. t. traillii) subspecies. To test subspecies limits, I reanalyzed available quantitative data on plumage coloration, and genetic variation in mitochondrial DNA and nuclear loci, and found no support for the distinctiveness of the Southwestern Willow Flycatcher. A test of niche divergence suggested that the Southwestern Willow Flycatcher does not have a significantly different climatic niche from its nearest geographic neighbor, E. t. adastus. I suggest that the Willow Flycatchers of the Southwest represent peripheral populations of an otherwise widespread species that do not merit subspecific recognition, and are therefore inappropriately listed as endangered under the ESA.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 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".