Comparative morphology of dark-eyed juncos<i>Junco hyemalis</i>breeding at two elevations: a common aviary experiment
Bibliographic record
Abstract
H. Bears (correspondence), M.C. Drever and K. Martin, Centre for Applied Conservation Research, University of British Columbia, 2424 MainMall, Vancouver, British Columbia, V6T 1Z4, Canada. Present address of H. B.: Rescan Environmental Services, 1111 West Hastings,Vancouver, B.C., V6E 2J3, Canada. Email: bears@zoology.ubc.caMorphologies of bird species often vary along elevation gradients, yet causes of the variation have not been examinedexperimentally. We investigated variation in morphological traits of the dark-eyed junco Junco hyemalis, breeding at1,000 m a.s.l. (low-elevation; i.e. low) and 2,000 m asl (high-elevation; i.e. high) in the Rocky Mountains, Canada. Eightmorphological traits were measured in free-living birds. We found two consistent differences in populations betweenelevations: at high-elevation sites, females had longer wings and males had longer tails than birds from low- elevationsites. Other age- and gender- specific results were observed in free-living birds between elevations: tarsi were shorter inhigh-elevation second year (SY) females and after second year (ASY) males, beak lengths were slightly longer in low-elevation SY females, and high-elevation ASY females tended to have lower fat than low-elevation ASY females.Morphological differences may result from genetic differences between elevations, or phenotypic flexibility resulting fromexposure to the different environmental conditions. To identify which mechanism caused the difference inmorphometrics, hand-reared birds from low- and high-elevation habitats were raised in identical conditions withunlimited access to high quality food until they had replaced all feathers. The traits measured in the lab (wing and rectrixlength, weight and fat score) tended to increase in magnitude compared to field values. Juncos from high- and low-elevations had similar responses to the aviary environment, with one exception: males from high-elevation sites hadgreater weight gain relative to free-living juncos than males from low-elevation sites. Thus, morphological traits in dark-eyed juncos were phenotypically flexible, capable of growing larger in the laboratory environment. However, there werealso persistent genetic or perinatal/maternal differences underlying population responses that prevented traits fromconverging under aviary conditions. As a result, trait size differences between high- and low-elevation populations weremaintained or exacerbated in the common aviary environment.
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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) | 0.001 | 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 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".