GBEATES SCAUP DUCK 157 



General distribution — Northern part of Northern Hemisphere. In North 

 America breeds from northwestern Alaska, Great Slave Lake, and central 

 Keewatin south to southern British Columbia and northern North Dakota; 

 ■winters from Maine to Florida and from the Aleutian Islands, Nevada and 

 Colorado south to southern California and southern Texas (modified from 

 A. O. TJ. Check-list, 1910, p. 75). 



Distribution in California — Fairly common winter visitant locally and 

 irregularly on salt and brackish water along the sea coast. Recorded south to 

 the vicinity of San Diego (Willett, 1912a, p. 25). Rare inland, as at Stockton, 

 San Joaquin County, and northward in central California (Belding, 1879, p. 

 446; and Belding, MS). 



The Scaup Ducks, or Blue-bills, are among the commonest of the 

 sea ducks. The Greater Scaup, however, is not so plentiful in most 

 parts of the United States as is the Lesser Scaup Duck, for the former 

 has a more northerly winter range. This statement holds for Cali- 

 fornia, for whereas the Greater Scaup is but occasionally met with, the 

 Lesser Scaup is found abundantly in winter on all of the coastal bays 

 and marshes, and often in the interior. Doubtless the Greater Scaup 

 is a commoner bird than is indicated by the comparatively few records ; 

 its habit of congregating with the smaller species, from which it 

 differs very slightly except for size, makes it easy to confuse with the 

 latter species. Records of the Greater Scaup in California, are limited 

 to the midwinter season save for a single bird taken at Stockton, San 

 Joaquin County, April 1, 1878 (Belding, 1879, p. 446), though there 

 are general statements to the effect that it occurs from October until 

 April. 



The black head with a slaty blue bill, the white belly and mantle, 

 and pure white speculum, conspicuous in flight, enable one to dis- 

 tinguish the male Greater Scaup from all other ducks except the 

 Lesser Scaup. In addition to a considerable difference in size, the 

 Greater Scaup can be separated from the Lesser by the metallic green 

 reflections on the sides of the head instead of the purplish ones to be 

 found in the Lesser Scaup Duck. The white mask formed by patches 

 of white about the base of the bill in the female separates her from 

 all other ducks except the female Lesser Scaup and Ring-necked. 

 Greater size alone is usually sufficient to separate her from either of 

 these two near-related species. In common with the male, her con- 

 trastedly dark head, and white belly and speculum, distinguish her 

 from most other ducks. 



The following description of the nesting site and nest of the 

 Greater Scaup in Alaska is given by Nelson (1887, p. 71). 



The nesting sites chosen are such as the Pintail and most other ducks 

 choose — a dry, grassy tussock or knoll close to some pond — the only difference 

 being that the present species appears to desire a position nearer water, . . . 

 and the nest is frequently at the point of some small jutting cape and so near 

 the water that the parent can swim to and from the nest. The nest is com- 



