Ambient temperature, body condition and sibling rivalry explain feather corticosterone levels in developing black kites

Summary In birds, the steroid hormone corticosterone ( CORT ) is considered a major mediator in a number of physiological mechanisms and behaviours critical for the regulation of an organism's energy balance. However, the question of whether the way in which circulating plasma CORT is incorporated into feathers actually reflects this regulation, and consequently whether feather CORT ( CORT ‐F) measures allow to make inferences on past levels of...