Linking demography, life-history theory and conservation of birds

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Ecologists are interested in factors affecting survival and reproductive rates of wild animals because these rates reflect the general health of wildlife and have an enormous impact on population size and persistence. In Canada, many migratory wildlife species are threatened by environmental changes resulting from local developments as well as impacts in other parts of the world. To achieve long-term objectives, my students and I will continue to test ecological theories to strengthen our understanding about the natural and human-related processes that affect distribution, abundance, and reproductive and survival rates of migratory birds. We will then use our new knowledge about these processes to recommend management programs or conservation initiatives and to improve the cost-effectiveness of these actions. Our main projects focus on migratory birds, and how characteristics of landscapes - particularly the intensity of agricultural land use - and nest sites influence individual quality of birds, and their survival and reproductive rates. We will measure food abundance during the nesting season of tree swallows (an aerial insectivore, a species that relies heavily on flying insects for food) on sites of varying agricultural intensification (and pesticide use) to evaluate how parental foraging and dispersal behaviours, physiology and survival may be modified by variable food supplies. For broader scope, we will also investigate reproductive ecology of two species of prairie-nesting ducks (mallard and pintail females) in relation to measurements of individual quality and landscape characteristics. Presumably, habitat preferences in animals are related to benefits such as higher reproductive success or survival, yet most studies of animals fail to link habitat selection to these key demographic rates. Using several unique data sets from well-replicated local and landscape-scale experiments, we will validate new indices of individual quality and test for positive correlations between demographic rates and habitat selection in tree swallows, pintails and mallards. Specifically, by incorporating a variety of innovative techniques, we will further validate the use of feather corticosterone (the "stress" hormone) as an integrated index of individual quality in diverse species; link survival and reproductive success to an individual's characteristics such as age and quality, nest site use and climatic conditions; and evaluate demographic consequences of nest site choices using powerful cross-fostering experiments. Importantly, these new Discovery Grant studies will: (i) clarify basic processes affecting survival rates and breeding success, (ii) apply this knowledge to identify management alternatives or to enhance the cost-effectiveness of conservation programs, and (iii) provide a stimulating, productive place for training emerging ecologists - individuals who will have to address increasingly complex environmental challenges, now and in the future.