Identifying risks to populations of migratory shorebirds

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The objective of my research program is to understand the degree of variability in an individual shorebird’s habitat selection patterns during breeding, migration and overwinter and to determine whether there is ongoing selection for habitat preferences. The overarching goal is to understand whether there is flexibility in habitat cues that will provide the ability for shorebirds to respond to changing habitats during each season (breeding, migration and overwintering) of the annual cycle. Links with fitness are critical for determining whether there is ongoing selection. These objectives can only be met using individually marked birds, of which we have sufficient numbers for analysis during all stages of the shorebird annual cycle, over the duration of the research program. In the Churchill, MB region marked populations of the three most commonly breeding shorebirds (Charadrius semipalmatus, Calidris alpina and Numenius phaeopus) exist, species for which my HQP have experience. My HQP also have historical data on breeding locations and associated reproductive success. During breeding I predict low repeatability of individual habitat preferences because breeding sites should be strongly selected to promote both survival of the adult breeder and reproductive success. For C. alpina and N. phaeopus I predict strong ongoing selection as a function of shrub and tree encroachment. During migration, in three locations along western James Bay, ON (Longridge, Little Piskwamish and North Point), with HQP I propose to use sightings of individually colour-banded birds as well as detections of those outfitted with nanotags, to document locations and associated geomorphological features and food resources. The three locations vary considerably in habitat features. We predict consistency in the choice of particular migratory stopover locations across years because of fitness advantages associated with familiarity of particular stopover sites. Consistency in movements over shorter time periods and to particular habitats within a location is not predicted because during migration there should be strong selection for individuals to track ephemeral and patchy food resources, and to avoid danger. During migration, mass gain, stopover lengths and departure times will be used as proxies of fitness. Finally, during the 8-9 mo non-breeding season HQP will study individual patterns of movements between foraging and roosting sites at two south temperate locations (in southeastern US) that vary in predation risk. We predict higher within and between season movements of both roost and foraging sites in the presence of predators. During non-breeding body condition and apparent survival will be used as estimates of fitness.