Linking life-history theory, demography 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. In Canada, many wildlife species are threatened by environmental changes resulting not only from local developments but also from impacts in other parts of the world. Populations of boreal-breeding lesser scaup have declined and remain well below conservation goals, whereas species like tree swallows are of conservation concern because of decreasing population trends in species that rely heavily on aerial insects for food. Our recent results suggest that new work is urgently needed on the life-cycle period from hatching to independence (or first breeding), so new Discovery Grant projects are designed to clarify why late-hatched offspring typically have lower survival than early-hatched individuals. This pattern could be related to seasonal reductions in parental quality or food abundance, or higher incidence and severity of diseases. Innovative experiments combined with long-term field data on tree swallows and lesser scaup will help to pinpoint the most likely explanation.