184 BULUETIN 126, UNITED STATES NATIONAL MUSEUM. 



here free of ice. Several specimens of pondweeds (Potamogeton) afford an abundant 

 food supply. By February 15, the flocks have reached their maximum and nimiber 

 several thousand. They remain in these large bands until March, when they move 

 north . A small number remain and breed. Males outnumber females in the propor- 

 tion of 15 to 1. Courtship commences about the last week in P'ebruary. This is 

 interesting in view of the fact that they are one of the last ducks to breed. 



DISTRIBUTION. 



Breeding range. — Central and western North America. Probably 

 breeds in Newfoundland (Sandy River) and has been found breeding 

 in southeastern Maine (Calais), Otherwise east to southeastern 

 Michigan (St. Clau' Flats) . South to southern Wisconsin (Lake Kosh- 

 konong) , southern Minnesota (Heron Lake), central western Nebraska 

 (Garden and Morrill Counties), southern Colorado (San Luis Valley), 

 northwestern New Mexico (Lake Burford) , southwestern Utah (Rush 

 Lake), central Nevada (Ruby Lake), and southern California (River- 

 side and Los Angeles Counties). West nearly to the coast in south- 

 ern California (Ventura County) , to the inland valleys farther north 

 (San Joaquin and Sacramento Valleys), central Oregon (Klamath and 

 Malheur Lakes), central Washington (east of the Cascade Mountains), 

 and central southern British Columbia (Swan Lake). North to 

 central British Columbia (LaclaHache), central Alberta (Edmonton), 

 Great Slave Lake (Fort Resolution rarely), central Saskatchewan 

 (Saskatchewan River), and south central Manitoba (Lake Winni- 

 pegosis) . 



Winter range. — Mainly in the southern United States. East to 

 the Atlantic coast and to the Bahamas. South to the West Indies 

 (Cuba and Jamaica), the Gulf of Mexico, and central western Mexico 

 (Manzanillo). West to the Pacific coast of Mexico and the United 

 States. North to southern British Columbia (Okanogan Lake), 

 southeastern Arizona (San Pedro River) , northeastern Colorado (Barr 

 Lake), northern Arkansas (Big Lake), probably southern Illinois, and 

 eastern Maryland (Chesapeake Bay). More rarely north to Lake 

 Erie and Ontario and southern New England. 



Spring migration. — Early dates of arrival : Indiana, central, March 

 6; Ontario, southern, March 14; Iowa, central, March 8; Wisconsin, 

 southern, March 10; Manitoba, southern, April 12; Maine, Scarboro, 

 March 27. Average dates of arrival: Ohio, Oberlin, March 10; 

 Ontario, southern, March 24; Iowa, Keokuk, March 7; Minnesota, 

 Heron Lake, March 26; Manitoba, southern, April 21. 



Fall migration. — Early dates of arrival: Ontario, southern, Sep- 

 tember 10; Virginia, Alexandria, October 5; Iowa, Iowa City, Octo- 

 ber 6; Missouri, St. Louis, October 16; Texas, San Angelo, October 1. 

 Average dates of arrival: Ontario, southern, September 19; Pennsyl- 

 vania, Erie, October 7; Virginia, Alexandria, October 12. 



