Will the Availability of Insular Nesting Sites Limit Reproduction in Urban Canada Goose Populations?

Abstract

Nonintigratory populations of Canada geese (Branta canadensis) in urban-suburban areas have been increasing in number and expanding into new areas during the last 3 decades e tested the hypothesis that the production of young by these urban goose populations was limited by the availability of insular nesting sites. To do so, we compared the nest success and reproductive rates of island nesters to mainland nesters, using a banded population of urban Canada geese in Connecticut. Nest success was similar (F = 0.18) for island nests (0.65) and mainland nests (0.55) More island nests were abandoned than mainland nests (P = 0.02), but more mainland uests were depredated (P = 0.01) and flooded (P = 0.01). Egg survival (proportion of eggs that hatcl from successful nests) was similar between island nesters (0.83) and mainland nesters (0.81; P = 0.61). Island nesters had larger clutches (5.3 t 0.1; x ± SE) than mainland nesters (4.4 ± 0.2; P = 0.01); hence, island nesters produced more goslings per uesting attempt (2.8) than mainland nesters (2.0). There was no difference between island nesters and mainland nesters in their age, mass, or prior breeding experience (Ps > 0.12). Our findings suggest availability of insular nesting sites may not play an important role in limiting reproduction of urban Canada goose populations.