Habitat Use and Activity Budgets of Greater Snow Geese in Spring

Abstract

During the past 2 decades, the greater snow goose (Chen caerulescens atlantica) has expanded its spring staging area from bulrush (Scirpus spp.) marshes in the upper Saint (St.) Lawrence River estuary [Quebec, Canada] to the cordgrass (Spartina spp.) marshes in the lower estuary. We compared the influence of tide, time of day, date, and weather on the activity budget of snow geese in the 2 marshes. Overall, geese staging in the bulrush marsh spent more time feeding than those staging in the cordgrass marsh (54 vs. 48%, respectively). Feeding and resting (the 2 major activities of geese) were primarily regulated by the tide cycle in the bulrush marsh. Time of day had little influence, and geese fed as much during the day as during the night. In the upper estuary geese used agricultural fields at high tide when the marsh was unavailable. However, in the cordgrass marsh tide had little effect on goose activity, but time of day had a strong influence as geese did not feed at night. Geese staging in this area spent more time feeding in the agricultural fields than those staging in the upper estuary (28 vs. 10%, respectively) and they showed a strong selection for new hayfields where small cereal grains and young grass were available. The increased dependence of geese upon agricultural habitat in the cordgrass marsh was a consequence of the low digestibility and poor quality of cordgrass rhizomes.