Chronology of Breeding and Molt Migration in Surf Scoters (Melanitta perspicillata )

Abstract

Little is known about the molt migration of the Surf Scoter (Melanitta perspicillata), a species endemic to North America. Our objective in this study was to document the breeding and molting chronology of Surf Scoters in Québec. Breeding birds were studied at Lake Malbaie, located about 90 km north of Québec City, Canada. Surf Scoters arrived at Lake Malbaie in the fourth week of May and most males stayed only for approximately three weeks. This relatively early departure of males from the breeding areas emphasizes the importance of salt water habitats for these birds. Unsuccessful adult females did not leave with the males but remained on their breeding lake. These females left the lake from mid to late July, nearly a month after the departure of males and much earlier than females with broods which left from mid to late August after abandoning their brood. This departure sequence was observed during the three years of the study. The difference in timing of molt migration between age and sex groups has important management implications as it potentially exposes them to different levels of mortality. For example, late molters, mostly adult females that bred successfully may still be flightless at the beginning of the hunting season in some areas. Better understanding of molt chronology and habitat selection by various sex and age groups will permit a more holistic and efficient management of Surf Scoters.