48 



NORTH AMERICAN FAUNA 73 



Migration: Fairly common migrant in the Western Upland and Central 

 Plain; common on forested lakes in the Northern Highland. Goddard (1975) 

 found that buffleheads constituted 1.6% of the total spring waterfowl popu- 

 lation and 3.5% of the diving duck population on prairie wetlands in central 

 St. Croix County. 



Spring migrants arrive in the Western Upland 20 March to 1 April 

 (earhest— 13 March 1966, Washington County) and peak populations occur 

 about 20 April. Migrants arrive in the Northern Highland 1-10 April, reach- 

 ing peak numbers 15-25 April. Departure from the Valley occurs by 25 May. 

 Fall migrants arrive in the Northern Highland about 1 October and the 

 Western Upland about 5 October. Peak fall populations occur 20 October to 

 1 November and departure occurs by 25 November. Peak fall populations on 

 central St. Croix County wetlands usually total 150 to 200 individuals. 



Summer: S. D. Robbins observed a lone bufflehead at Crex Meadows, Bur- 

 nett County, on 17 June 1976. This may have been an injured bird. 



Winter: A flock of 40 buffleheads was observed on the St. Croix River near 

 Grantsburg, Burnett County, from 12-13 January 1949 (Robbins 1949). 



Habitat: Buffleheads are associated with a variety of wetland types during 

 spring migration, including temporarily, seasonally, and permanently 

 flooded wetlands, and riverine habitats. During fall migration buffleheads 

 are usually associated with large semipermanently and permanently flooded 

 wetlands. 



Oldsquaw {Clangula hyemalis) 

 Status: Casual, five records. 



Records: Oldsquaw were observed on Oakridge Lake near New Richmond, 

 St. Croix County, on 24 October 1974 (S. R. Schneider); 14 October 1975 

 (R. E. Faanes); and 2 October 1977 (C. A. Faanes). One was observed at Crex 

 Meadows Wildlife Area, Burnett County, on 22 April 1952 (Strelitzer 1952). 

 In Washington County, three birds were observed on 6 January 1965. 



Common Eider (Somateria mollis sima) 

 Status: Accidental, one record. 



Record: One female common eider was shot on Phantom Lake, Crex 

 Meadows Wildlife Area, Burnett County, on 10 November 1968 (Tessen 

 19696). 



White-winged Scoter (Melanitta deglandi) 

 Status: Casual, four records. 



Records: N. R. Stone observed one at Crex Meadows, Burnett County, on 

 8 May 1950 (Robbins 19506), and R. Brown observed one there on 12 Au- 

 gust 1975. C. A. Faanes and W. Norling observed a female on Oakridge 



