U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

September 2004




Resident Canada goose (Branta canadensis) and human populations in North America are increasing rapidly. Consequently, human-goose conflicts also are increasing. A potential approach to manage Canada goose populations is the use of orally delivered reproductive inhibitors. Nicarbazin, when ingested daily, is a reproductive inhibitor that has the potential to reduce the hatchability of Canada goose eggs. To successfully employ reproductive inhibition, managers must understand the behavior of local Canada goose populations, primarily springtime movements, nesting, and habitat use to develop effective methods for delivering necessary doses. We monitored movement, habitat use, and nesting of 51 resident Canada geese, all adult females, at Bay Beach Wildlife Sanctuary (BBWS), Green Bay, Wisconsin, during 2001 and 2002. Our objective was to determine if geese were sufficiently sedentary during the nest initiation period to allow effective dosage with nicarbazin to assess its potential as a management tool. Our results indicated some geese never departed the area and were available for daily dosing while others departed and never returned. Goose movements and time spent away from BBWS were highly variable among geese; individuals traveled <1 km to 109 km from BBWS. However, movement patterns of individuals did not vary markedly between years. Similarly, nest sites were widely variable among geese but were consistent among years within individuals. Habitat use varied considerably among geese and included industrial complexes, urban lawns and parks, agricultural fields, and remote marshes. Overall, there was high variability among Canada geese in movement patterns, nesting, and habitat use. Such variability presents difficulty in delivering required doses of nicarbazin, or other reproductive inhibitors that must be ingested daily prior to and during egg laying.