Staging, Migration, and Winter Distribution of Canada and Cackling Geese Staging in Interior Alaska

Abstract

The breeding stock composition and ecology of Canada (Branta canadensis) and cackling (B. hutchinsii) geese, collectively white-cheeked geese, staging in interior Alaska and wintering in the Pacific Northwest is poorly understood. We captured, measured, and applied neck collars to white-cheeked geese during spring and fall staging near Fairbanks and Delta Junction, Alaska, USA, to study their breeding stock composition, migration, and winter distribution. We measured exposed culmen, flattened wing chord, total tarsus, and body length of geese staging in interior Alaska to assist with determination of breeding stock. The first principal components, as well as a univariate measurement of exposed culmen, indicated geese trapped in Fairbanks in the fall were larger on average than geese trapped in Delta Junction in either spring or fall. We observed or recovered most of the banded geese detected in fall and winter in central British Columbia, Canada, central Washington, USA, and north-central Oregon, USA, east of the Cascade Mountains, with relatively few observations in western British Columbia, Washington, and Oregon. We found no evidence of movement between wintering areas on the east and west sides of the Cascade Mountains. Geese that we trapped during spring staging in Delta Junction were more often observed on the west side of the Cascade Mountains than geese trapped during fall staging in Fairbanks. Most (93%) geese trapped during fall staging in both Fairbanks and Delta Junction, however, wintered east of the Cascade Mountains. After-hatch-year (AHY) geese from interior Alaska staging areas observed on the west side of the Cascade Mountains were structurally smaller on average than AHY geese observed on the east side of the Cascade Mountains. Our results indicate fall staging white-cheeked geese in Fairbanks were predominantly 1 breeding stock of white-cheeked geese, while fall and spring staging white-cheeked geese in Delta Junction comprised at least 2 stocks of white-cheeked geese. Based on our findings, we recommend separate harvest and management strategies be considered for small white-cheeked geese migrating through coastal and central British Columbia and wintering east and west of the Cascade Mountains in Washington and Oregon to avoid potential overharvest of independent breeding stocks.