Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The global population is estimated to number c.250,000-1,300,000 individuals (Wetlands International 2006), while the population in Russia has been estimated at <c.100 breeding pairs (Brazil 2009).
The overall population trend is decreasing, although some populations have unknown trends (Wetlands International 2006). This species has undergone a small or statistically insignificant decrease over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007) Note, however, that these surveys cover less than 50% of the species's range in North America.
The Surf Scoter can be found in North America, breeding inland from western Alaska (USA) through central Canada to Labrador, and wintering from the Aleutian Islands down to Baja California (Mexico) on the Pacific coast, and along the Atlantic coast of the USA as far south as South Carolina (del Hoyo et al. 1996) .
This species breed on small bodies of fresh water in boreal forests or tundra, wintering at sea in shallow waters of bays, eastuaries and river mouths. It feeds chiefly on molluscs, but also eats crustaceans, worms, echinoderms and, mainly in summer, insects and their larvae and plant material, feeding mostly by diving. Its breeding season begins in May or June, breeding in single pairs or loose groups in shallow depressions poorly lined with grass and some feathers (del Hoyo et al. 1996) .
Text account compilers
Ekstrom, J., Butchart, S., Calvert, R.
BirdLife International (2017) Species factsheet: Melanitta perspicillata. Downloaded from http://www.birdlife.org on 11/12/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 11/12/2017.