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NORTH AMERICAN FAUNA 73 



be determined because of low numbers. Nonbreeding migrants have 

 departed by 20 May. The first fall migrants arrive 25 September to 5 Oc- 

 tober and the last depart by 1 November (latest— 10 November). During 

 both seasons migrants are usually observed in central St. Croix County and 

 at several areas along the St. Croix River in Washington, Polk, and St. Croix 

 counties. 



Nesting Season Distribution: The red-necked grebe is a very rare and local 

 nesting species. Green and Janssen (1975) showed a nesting record for 

 Washington County. Apparently this species no longer nests on the Minne- 

 sota side of the St. Croix River. Presently, nesting occurs only on prairie 

 wetlands in central St. Croix and extreme southern Polk counties. 



The first nesting for the Valley in Wisconsin was recorded in 1973 from 

 East Twin Lake near Roberts. During the summer of 1976, three pairs pro- 

 duced young on Twin Lakes and an additional pair was successful on Oak- 

 ridge Lake near New Richmond. In 1977, four pairs produced young on Oak- 

 ridge Lake, one pair on East Twin Lake, and a sixth pair produced young on 

 a small wetland near Star Prairie in Polk County. During 1978-79 breeding 

 populations were greatly reduced with activity restricted to Oakridge Lake 

 (M. Schmidt, personal communication). 



Habitat: All 12 nesting records have been obtained on semipermanently and 

 permanently flooded wetlands. These wetlands range in size from 8.5 to 

 93 ha. Extensive beds of submerged aquatic plants are present on these wet- 

 lands. All nests have been located in large beds of soft stem bulrush. 



Horned Grebe (Podiceps auritus) 



Status: Regular migrant, casual nesting species. 



Migration: Common migrant throughout the Valley. Spring migrants begin 

 to arrive in the Western Upland during the second week of April (earliest— 

 24 March) and the Northern Highland 1-5 May. Peak abundance occurs dur- 

 ing the first week of May and departure by 15 May. FaU migrants begin to 

 arrive during the third week of September. Peak abundance occurs about 

 15 October when occasional flocks of 50 to 60 individuals are observed on 

 larger lakes. Fall migrants have departed by November 20. 



Nesting Season Distribution: One nesting record exists for this region. On 

 2 July 1951 an adult with a brood of four was observed at the Crex Meadows 

 Wildlife Area, Burnett County. On 14 June 1974, I observed an adult in 

 breeding plumage near Range, Polk County. 



Habitat: Horned grebes use a wide range of wetland classes including sea- 

 sonally, semipermanently, and permanently flooded wetlands. In the North- 

 ern Highland, extensive use is made of Forest Bordered Wetlands and occa- 

 sional use is made of acidic bog wetlands and larger rivers. The Burnett 

 County nesting pair were using a large sedge meadow wetland. 



Eared Grebe {Podiceps nigricollis) 



Status: Regular spring and casual fall migrant; four summer records. 



