Population and habitat of wintering Brent Geese Branta bernicla in eastern Oshima Peninsula, Tsugaru Strait and Mutsu Bay

Abstract

The population and habitat of Brent Geese Branta bernicla were investigated in the species' main wintering area in Japan (around the Tsugaru Strait) in late December 2012. A total of 1,060 individuals was found, most of which occurred in southeast Oshima Peninsula and southeast Mutsu Bay. Goose density was higher in areas with artificial revetments and rocky shore, where marine algae (the main diet of the geese) grow easily. Coastlines with offshore structures were selected as feeding habitat because eelgrass Zostera marina grows there and because wave washed seaweed can accumulate inshore of such structures, where waves are calm.