34 



NORTH AMERICAN FAUNA 73 



breeding pairs occur in sedge meadows in this region, as well as edges of 

 Black Spruce-Tamarack Bog and northern Forest Bordered Lakes. 



FAMILY ANATIDAE: Swans, Geese, and Ducks 



Whistling Swan (Olor columhianus) 

 Status: Regular migrant, two summer records. 



Migration: Common to locally abundant spring migrant in the Western 

 Upland, fairly common in the Central Plain and uncommon in the Northern 

 Highland. Spring migrants arrive about 25 March in the Western Upland 

 and by 15 April in the Northern Highland. Peak spring migration occurs 

 10-25 April. During this period, flocks of 300 to 400 birds are frequently 

 observed, primarily on the prairie wetlands of St. Croix and Washington 

 counties. Roberts (1932) cited the passage of about 2,000 whistUng swans 

 through the Valley during "the spring of 1923." Departure is very rapid; 

 most birds are gone by 10 May (latest— 13 May 1975, Burnett County). 



Fall migration begins with the arrival of the first birds in the Northern 

 Highland about 5 October. Small groups of swans slowly move into the 

 region during most of October. Peak fall migration occurs 25 October to 

 15 November. Currently, peak concentrations range from 100 to 300 indi- 

 viduals. Roberts (1932) described the observation of "several mixed flocks of 

 swans and geese, one numbering 1,200 to 1,500 birds" at Stillwater. Dates of 

 peak numbers vary considerably and are dependent upon the advancement 

 of northern cold fronts. Departure from the region usually occurs by 1 De- 

 cember and is dependent upon the amount of ice formed on area waters. 



Summer: A lone whistling swan was observed at Crex Meadows, Burnett 

 County, on 26 June 1957 (Lound and Lound 1957c?). A single bird remained 

 in St. Croix County during the 1979 summer (Tessen 19796). Both birds were 

 probably injured. 



Habitat: Migrant whistUng swans utiUze a variety of wetland types during 

 migration. In spring, whistUng swans are usuaUy found feeding in numerous 

 temporarily flooded wetlands which are fertile. Larger semipermanently and 

 permanently flooded wetlands are used in spring, primarily as roosting sites. 

 During faU migration swans utiUze the larger permanently flooded wetlands 

 and open riverine habitats. 



Canada Goose (Branta canadensis) 



Status: Regular migrant and nesting species, casual winter resident. 



Migration: Common to locally abundant migrant throughout the region, 

 especially numerous along the St. Croix River and in central St. Croix, 

 Washington, and southern Burnett counties. Arrival of the first spring 

 migrants in the Western Upland occurs 20-25 February and they have 

 reached the Northern Highland (Burnett County) by 10 March. Peak spring 

 migration occurs 25 March to 20 April. Largest numbers of migrants 

 usuaUy occur at the Crex Meadows WildUfe Area, Burnett County. 



