LE3 .A278 2017

2017

Shutler, Dave

Acadia University

Bachelor of Science

Honours

Biology

Biology

Many seabirds nest at high densities on islands to escape mammalian predators and to take advantage of group defense against avian predators. However, costs of choosing islands may include competition for nest sites. Some species nest underground which may provide additional protection against avian predators and provide a stable microclimate. If group defense provides a net benefit, nests that are closer together (shorter nearest neighbor distances) should have higher nest success. Seabirds that nest underground in soil should favor intermediate moisture conditions to avoid burrow crumbling or flooding. I investigated nest site selection and reproductive success by Leach’s storm-petrels (Oceanodroma leucorhoa), a colonial seabird that nests in burrows on offshore islands. A total of 396 burrows was monitored on Bon Portage Island, Nova Scotia, Canada. Soil moisture was higher at control points (one meter north from burrow entrances) than at burrow entrances, but there was no difference in moisture at occupied versus unoccupied or successful versus failed burrows. Nearest neighbor distance did not appear to be associated with nest success. These results suggest that nesting by Leach’s storm-petrels may be sensitive to soil moisture, and that there may be an optimal soil moisture range for excavating burrows.

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https://scholar.acadiau.ca/islandora/object/theses:2077