Ecology and evolutionary biology of stress in birds

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My general objective is to study causes and consequences of stress in birds from a life history perspective. Stress is ubiquitous in the lives of animals with pervasive consequences to their well being. How individuals perceive, respond to and cope with stressors is crucial to an animal's physiology, behaviour and ecology. How physiological mechanisms mediate the relationship between the animal and its environment help us better understand the diversification of life histories, i.e., strategies to optimize the allocation of limited resources. Life history trade offs are particularly notable when animals are exposed to stressors for they must allocate limited resources (e.g. energy, nutrients such as carotenoids, immune function) between the competing demands of dealing with the stressor and maintaining condition. The testable hypothesis is that the optimal strategy should vary with the cost to individual condition and nature of the stressor. I use both wild and captive birds to study stress in the context of reproductive effort, sexual ornamentation and how birds deal with anthropogenic disturbances. Although I will assess condition, health and stress in many ways, I will especially use a novel technique I developed for quantifying corticosterone (stress hormone) in feathers that allows for a long-term evaluation (days to months) of stress physiology. I will manipulate such stressors as parasite loads, diet, food supply and environmental temperature to investigate the role of stress in mediating such trade offs as parental effort vs condition, and number vs quality of offspring. Similarly, I will investigate experimentally how corticosterone and testosterone mediate trade offs between the use of carotenoids for coloration of sexual ornaments vs. immune function. I also directly manipulate hormone levels with implants, and pharmacologically test the capacity of components of the hypothalamic-pituitary-adrenal (stress) axis that may help explain the great variation within and among species in their response to, and consequences of, stress. The novelty of my approach will take the field of stress research in new directions, with impacts in basic science, veterinary medicine, animal husbandry, conservation biology and wildlife management.