Bibliographic record
Abstract
ABSTI•CT.--WillowPtarmigan (Lagopus lagopus) in the winter plumage, on a regime under which control birds grew white feathers in plucked areas, grew pigmented feathers in the plucked areas, when injected with posterior pituitary extract or a MSH, LH, or FSH (only effective in females).White-tailed Ptarmigan (Lagopus leucurus), patch-plucked and released into the wild after implantation with a hormone-cholesterol mixture, grew pigmented feathers after implantation with a MSH, TSH, thyroxine (in one out of two birds tested), and an FSH/LH mixture.Controls implanted with cholesterol grew only white feathers.Both sets of experiments were carried out in winter.A scheme of the control of ptarmigan plumage colors, which assumes that MSH and gonadotrophins and, in males, testosterone are involved in the natural control mechanism, is proposed.ALL three species of ptarmigan have a white winter plumage that is followed by a pigmented summer (or nuptial) and a pigmented fall plumage.In Willow Ptarmigan (Lagopus lagopus), only the male further develops a pigmented breeding plumage preceding the summer plumage (Johnsen 1929).This plumage is not recognized as a distinct entity by some.The experiments of HOst (1942) and of Novikov and Blagodatskaia (1948) demonstrated that daylength is the main external factor that determines timing of the molts as well as the feather pigmentation involved in the seasonal color changes.They reported that artificial long days could induce a premature molt into the pigmented breeding or summer plumage in captive Willow Ptarmigan, in spite of low normal winter temperatures.Phenological observations on Rock Ptarmigan (Lagopus mutus) (Salomonsen 1939, Hewson 1973, Watson and Moss 1973) suggest that ambient temperature can also affect molts and feather color.Because long days can induce a premature spring molt in Willow Ptarmigan kept at a low temperature (HOst 1942, Novikov and Blagodatskaia 1948), the effect of temperature must be secondary to that of daylength.It is unlikely that external factors act directly on feather follicles and more probable that their effect is mediated by hormones.Novikov (1939) was the first to investigate the role of hormones in ptarmigan molts and plumage color.He removed the gonads of Willow Ptarmigan of both sexes in winter and reported that these birds later molted at the usual time into the normal succeeding pigmented plumage.Stokkan (1979), however, found that the male breeding plumage of these birds depends upon testosterone.His castrates, like those of Novikov, were operated on in winter, but after the next molt they assumed the summer, not the breeding, plumage.Possibly Novikov did not distinguish these two plumages.Novikov and Blagodatskaia (1948) investigated the role of the thyroid in the control of Willow Ptarmigan plumages.They reported that in three birds thyroidectomized during the spring molt the new feathers were white, but in controls they were pigmented.Feeding 200 mg thyroid powder daily to intact winter birds induced an unseasonal molt followed by pigmented new feathers, while controls under these 601The Auk 97: 601-607.
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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 | 0.000 | 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".