Black Scoter and White-winged Scoter

Rhodes, Walt
South Carolina Dept of Natural Resources
Publication Date: 

Black and white-winged scoters are not federally listed species but are protected under the
Migratory Bird Treaty Act. The North American Waterfowl Management Plan (2004) lists all
scoter species as decreasing in numbers in North America.

Black and white-winged scoters are classified in family Anatidae, subfamily Anatinae and tribe
Mergini. The tribe Mergini is represented mostly by the sea ducks, although some species in this
tribe will inhabit freshwater habitats. Species within this tribe are differentiated from the other
tribe of diving ducks, Aythyini (bay ducks), because members do not breed until their second
year and complete elaborate courtship displays that bear little resemblance to other ducks

Because it is difficult to differentiate among the three species of scoters from a fixed-winged
aircraft, scoter species are lumped together during spring breeding surveys. Within the
traditional area of the Waterfowl Breeding Population and Habitat Survey, scoters as a group appear
to have declined. Scoters species are also noted in the Eastern Survey Area, a more recent
breeding waterfowl survey conducted since 1990. Comparable estimates from 1996 through
2004 demonstrate an increased population, with estimates numbering over 200,000 birds
(Serie and Raftovich 2004).

Christmas Bird Count and midwinter waterfowl survey data are also highly variable. Black
scoters have been recorded every year since 1961 in Christmas bird counts. Numbers have
ranged from 1 to 5,400 and averaged approximately 750 birds. White-winged scoters were
observed much less frequently and in lower numbers. The first observation was of three whitewinged
scoters in 1940. The highest number documented on a Christmas bird count was 532 in
1983. White-winged scoters have been recorded in 17 of the last 25 counts but have typically
numbered less than 25 birds. Scoters are not differentiated during the midwinter waterfowl
survey but nearly all of the scoters seen are black scoters (W. Rhodes, pers. obs.). Scoter species
numbers have been variable since 1955, with most birds seen during the last 20 years (the
average is 3,500 birds). Post and Gauthreaux (1989) stated black scoters were an abundant
winter visitor while white-winged scoters were uncommon. They note only a few sightings
away from the coast for each species.
Black and white-winged scoters are found in the littoral zone of the Atlantic Ocean