Annual regulation of adrenocortical function in migrant and resident subspecies of white-crowned sparrow.

摘要: Abstract Corticosterone affects physiology and behavior both during normal daily processes but also in response to environmental challenges is known mediate life history trade-offs. Many studies have investigated patterns of corticosterone production at targeted times year, while ignoring underlying annual profiles. We aimed understand the regulation hypothalamic-pituitary-adrenal (HPA) axis function migrant (Zonotrichia leucophrys gambelii; n = 926) resident (Z. l. nutalli; n = 688) subspecies white-crowned sparrow how it influenced by conditions – wind, precipitation, temperature. predicted that more dramatic seasonal changes baseline stress-induced would occur migrants precisely time onset breeding cope with extremes on their arctic grounds, residents be muted as they experience a forgiving schedule comparatively benign coastal California. During course harshest were experienced summer grounds for migrants, which point had higher levels compared residents. For residents, winter months coincided than migrants. subspecies, tended rise became colder windier. found maxima occurred prior egg lay all birds except females. Migrants much acute residents; where harsher environment timing reproduction critical because season shorter. Interestingly, molt was only stage within cycle differences absent suggesting requisite reduction may met feather growth. These data suggest modulation HPA largely driven factors, social cues, potential interactions genetic program.