American Kestrel (Falco sparverius) Science Article 18
abstract
Although it is well documented that hatching asynchrony in birds can lead to competitive and developmental hierarchies, potentiallygreatly affecting growth and survival of nestlings, hatching asynchrony may also precipitate modulations in neuroendocrine developmentor function. Here we examine sibling variation in adrenocortical function in postnatally developing, asynchronously hatching Americankestrels (Falco sparverius) by measurements of baseline and stress-induced levels of corticosterone at ages 10, 16, 22, and 28 daysposthatching. There was a significant effect of hatching order on both baseline and stress-induced corticosterone levels during developmentand these effects grew stronger through development. First-hatched chicks exhibited higher baseline levels than later-hatched chicksthroughout development and higher stress-induced levels during the latter half of development
Oliver P. Love, David M. Bird, and Laird J. Shutt, Hormones and Behavior 43 (2003) 480-488