Immediate and delayed effects of poor developmental conditions on growth and flight ability of juvenile mourning doves Zenaida macroura

Abstract

Adaptations that minimize the effects of stress are important components of avian development and have a role in structuring the relationship between development and fitness. I examined the effect of experimental manipulations of developmental stress during the nestling and fledgling stages on weight gain, growth in structural size, and take-off flight speed of juvenile mourning doves Zenaida macroura. Brood size was manipulated during the nestling stage (≤11 days) and feeding rates during the fledgling stage (13–25 days) using a full factorial design. Effects of nutritional stress differed between the two treatments and depended on the response that was measured and the age at which it was measured. Treatment effects on flight ability were delayed and were greater for the treatment during the nestling stage than during the fledgling stage. Immediate treatment effects were greater than delayed effects on weight and size. Young were able to minimize effects of stress on flight ability at early ages when they would be most vulnerable to predation. However, by 90 days birds from enlarged broods were slower and flight time at 90 days was negatively correlated with weight and size at 25 days. There was no evidence for a cost of compensatory growth after experimental treatments ended on flight ability at 90 days. Results suggest that the effects of stress occur in a hierarchical manner across phenotypic components and that at early ages flight ability is prioritized through phenotypic plasticity.