Corticosterone exposure during development improves performance on a novel foraging task in zebra finches

Developmental stress affects a range of phenotypic traits in later life-history stages. These long-term effects are thought to provide information to potential mates on individual quality and the ability to cope with adversity (i.e. the developmental stress hypothesis). Developmental stress appears to affect learning broadly, but the direction of effect is not always consistent between studies. This disparity may arise from indirect effects of developmental stress on other physiological or behavioural systems, which can affect outcomes in learning paradigms. Here, we examine the effect of elevated corticosterone (the dominant avian stress hormone) during development on the ability of zebra finches, Taeniopygia guttata, to learn a novel foraging task as adults. Additionally, we evaluate treatment effects on metabolism, to determine whether changes in metabolic rate indirectly alter learning results. We found that birds exposed to elevated corticosterone during development solved a foraging task faster than control siblings. This outcome could result from differences, not in learning ability, but in motivation for reward. However, we found no difference between treatment groups in metabolic rate. Hence, our results indicate that developmental stress can increase learning ability, and suggest that the effects of stress will vary based on the type of learning studied.