SITE FIDELITY OF BLACK BRANT WINTERING AND SPRING STAGING IN THE STRAIT OF GEORGIA, BRITISH-COLUMBIA

Site fidelity has important implications for population genetics and d ynamics. In birds, most studies have dealt with breeding ground fideli ty, ignoring the fact that waterfowl mainly pair in winter or early sp ring. We used multiple observation data from a mark-resight study of B lack Brant (Branta bernicla nigricans) to estimate fidelity to winteri ng and spring staging areas in Boundary Bay and Parksville-Qualicum, B ritish Columbia. Site fidelity was low for winter residents but still indicated that Brant were faithful to Boundary Bay. Birds seen twice o r more during any given winter had significantly higher site fidelity rates than those seen only once. The models for the spring period show ed the presence of transients in both Boundary Bay and Qualicum. Birds seen for the first time in an area had a lower probability of returni ng to that area than birds seen in mere than one year. Survival probab ility was significantly higher for Qualicum birds than for Boundary Ba y birds. We concluded that prior knowledge of an area was an important determinant of site fidelity, and that low sire fidelity levels were unlikely to lead to genetic substructuring of the population.