Black Scoters

Surf Scoters Photos © Patty Wainright

White-winged Scoters

Scoter Breeding Ranges Map © Google with modifications

Scoters

Scoters at a glance

Taxonomy

Order Anseriformes (includes screamers, ducks, geese, and swans)
Family Anatidae (includes ducks, geese, and swans)
Subfamily Anatinae (true ducks)
Tribe Mergini (sea ducks and mergansers)
Genus and species:

   Black Scoter - Melanitta [nigra] americana
   Surf Scoter - M. perspicillata
   White-winged scoter - M. fusca [deglandi]

Other sea ducks along coastal waters: eiders, goldeneyes, buffleheads, Harlequin Ducks, Long- tailed Ducks, mergansers, and the extinct Labrador Duck.
Share in their diving skills, seawater tolerance, compact plumage, heavy down, and preference for animal foods.

Identification

Medium size (19-21” long; 28-34” wingspan; 2-4 lb.)
Black scoter – male is all black with yellow knob on bill
Surf scoter – male is all black, white head patches with red, and yellow and white bill
White-winged scoter – male is all black with white comma below eye, white wing patch, and orangish-yellow bill
Females are mostly grey-brown, with a greyish-bill.

Behavior/Habitat

Form small to large flocks on the ocean or bay and, sometimes associated with other sea ducks
Fly in small to large flocks into Casco Bay at daybreak and return to sea before sunset
Dive for prey using their wings to “swim”
Feed on invertebrates and sometimes small fish

Migration

All three species in North America migrate from Alaska and Canada down the East and West coasts (See map)

Breeding/Nesting

Breed in northern latitudes (See map)
Nest in May and June in scrapes or depressions in ground, lined with grass and down/feathers
Incubation of 6-9 eggs for ~30 days and fledge in ~50 days
Sexually mature in 2-3 years with oldest marked birds 12-16 years

Reference
[old name]=Eliminated by American Ornithological Union

American Ornithological Union(AOU) and International Ornithological Union (IOU):
http://checklist.aou.org
http://www.worldbirdnames.org/ioc-lists/master-list-2/

Full Species Account

Three species of scoters spend their winters in Casco Bay after migrating great distances from their northern breeding grounds: Black Scoters, Surf Scoters, and White-winged Scoters. Black Scoter males are all black with a yellow knob on the bill. Surf Scoter males are mostly all black with white head patches and a multicolored bill. White-winged Scoter males are all black with a white ‘comma’ below the eye and white wing patch. Female scoters have less dramatic plumages and they have only gray beaks.

Black Scoters visiting Casco Bay in the winter, most likely breed in the wetlands of Labrador and eastern Quebec. Other possible sources of Casco Bay Black Scoters include a small area of southern Nunavut Province, the tip of southern Greenland, and most western Alaska.

Surf Scoters have an even larger breeding area covering most of Alaska, and the Yukon and Northwest Territories of Canada – some of this breeding area is above the Artic Circle. Another area where the Surf Scoters breed overlaps that breeding range of the Black Scoter in Labrador and Quebec.

The White-winged Scoter’s breeding range is the largest of the three scoters extending from Alaska, throughout the western Canadian Provinces/Territories to Hudson Bay. Some of these scoters overwinter along the West Coast of North America. Others undergo a more costly journey by flying across Canada to the East Coast of NA, including Maine.

From autumn to early spring White-winged Scoters are seen feeding in small groups close to Peaks Island Backshore. The Black Scoters are usually in large flocks that sometimes mix with the Common Eiders, whereas the Surf Scoters are less abundant; they are often seen in mixed flocks or isolated in small groups. Numerous scoter flocks also fly in loose and wavy formations into Casco Bay at daybreak and leave the Bay at sunset to rest at sea.

Scoters search for prey by diving, using their wings to ‘fly’ underwater. They feed on invertebrates (including the invasive green crab species), and occasionally on small fish.

References

del Hoyo, J., Elliott, A., and Sargatal, J. eds. (1992). Handbook of the Birds of the World. Vol. 1. Lynx Edicions, Barcelona (pages: 312-325; 536-628).

Sibley, D.A. (2000). National Audubon Society: The Sibley Guide to Birds. Alfred A. Knopf, Inc. NY (pages: 54; 98-99).

Written by: Patty Wainright

Reviewers: Michelle Brown, Linda Sauerteig, Sam Wainright