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Avian Developmental Endocrinology: The Effects And Role Of Yolk Hormones, Sibling Dynamics, And Life-History, Corinne Patricia Kozlowski

Dissertations

Inter-specific variation of the endocrine system is an underlying component for variation in avian life-history. Females deposit hormones into the yolks of their eggs, and embryonic exposure affects nestling phenotype. Hormones are also produced endogenously by developing nestlings, further influencing their behavior and physiology. This dissertation examines the role of the endocrine system in development by focusing on several different avian taxa. Yolk hormone concentrations often vary across the laying order and may mediate hatching asynchrony. These patterns were characterized in two species that lay asynchronously hatching clutches: Eastern screech owls (Megascops asio) and cockatiels (Nymphicus hollandicus). The patterns described …