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Winter androgen levels and wattle size in male common pheasants

Article Abstract:

Studies have shown that female choice in the Common Pheasant is influenced by characteristics of some male ornaments, such as tail length and the occurrence of black points in the wattle. Morphological and hormonal measurements of 101 male Common Pheasants were made to determine correlates of ornament size. Wattle size was positively linked with androgens in January, although not in February. Androgen rates were bimodally distributed in January with one group with low hormone levels, and another group with high levels. Log transformed androgen levels were normally distributed in all males in February.

Physiological aspects, Pheasants

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Effects of winter weather on horizontal and vertical use of isolated forest fragments by bark-foraging birds

Article Abstract:

A study undertook to determine if permanent-resident bark-foraging birds avoided microclimate edge effects by foraging further from windward edges and at lower heights. The potential influence of microclimatic edge effects on the distribution of woodland birds was also considered. all mixed-species flock members, apart from female Downy Woodpeckers, were found away from windward edges when wind speeds were higher and temperatures lower, indicating that wind and temperature are important ot bark-foraging birds.

Environmental aspects, Forest birds

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Sleep-vigilance trade-off in Gadwall during the winter period

Article Abstract:

Research concerning the sleep-vigilance patterns in Gadwalls overwintering in the Camargue, France, during the winters of 1992-93 and 1994-95, are presented. Differences in sex did not appear to affect these patterns.

Behavior, Birds, Ducks, Animal wintering

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