Human-Wildlife Interactions (Feb 2017)
Movements, Habitat Selection, Associations, and Survival of Giant Canada Goose Broods in Central Tennessee
Abstract
The brood-rearing period in giant Canada geese (Branta canadensis maxima) is one of the least-studied areas of goose ecology. We monitored 32 broods in Putnam County, Tennessee, from the time of hatching through fledging (i.e., when the goslings gained the ability to fly) and from fledging until broods left the brood-rearing areas during the spring and summer of 2003. We conducted a fixed-kernel, home-range analysis for each brood using the Animal Movement Extension in ArcView® 3.3 GIS (ESRI, Redlands, Calif.) software and calculated 95% and 50% utilization distributions (UD) for each brood. We classified 25 broods as sedentary (8 ha 95% UD), three as shifters (84 ha 95% UD), two as wanderers (110 ha 95%UD); two were unclassified because of low sample size. We measured 5 habitat variables (i.e., percentage of water, percentage of pasture, percentage of development, number of ponds, and distance to nearest unused pond) within a 14.5-ha buffer at nesting locations. We used linear regression, using multi-model selection, information theoretic analysis, to determine which, if any, habitat variables influenced home-range size at a landscape level. The null model was the best information-theoretic model, and the global model was not significant, indicating that landscape level habitat variables selected in this study cannot be used to predict homerange size in the Upper Cumberland region goose flock. We analyzed associations among broods, using a coefficient of association of at least 0.50, and determined association areas by overlaying individual home ranges. Overall gosling survival (Ŝ) during the brood-rearing period was 0.84 (95% CL = 0.78, 0.92), using a staggered-entry Kaplan-Meier survival curve. We believe that abundance of quality forage and pond habitat, high survivorship, and a lack of movement corridors (i.e., rivers, lakes, and reservoirs) were responsible for the relatively small home ranges of geese in the Upper Cumberland region. Associations formed during brood rearing may reduce predation risks and serve as a template for lifelong social bonds with family members and unrelated geese that are reared in the same locations.
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