BIRDS OF THE ST. CROIX RIVER VALLEY 



27 



Migration: Rare migrant in the Western Upland and Central Plain. There are 

 no records except from Crex Meadows in the Northern Highland. Spring 

 migrants begin to arrive during the last week of April (earliest— 20 April 

 1975, Polk County) and remain through 5 June. Sightings are most often of 

 single or paired birds. Dates for fall migrants are too few to establish a pat- 

 tern. Fall observations are rare, noted between 10-20 September. 



Nesting Season Distribution: One nesting record exists for the Valley. S. D. 

 Robbins found an adult carrying young on its back during the summer of 

 1968 on East Twin Lake near Roberts, St. Croix County (Robbins 1969a). 

 This is the only known nesting record of the eared grebe in Wisconsin. On 21 

 July 1952, three eared grebes were observed on Phantom Lake, Crex 

 Meadows, and on 12 July 1956, a single bird was observed at Crex Meadows 

 (Lound and Lound 19566). During the summer of 1977, a single adult 

 remained on Oakridge Lake, St. Croix County, until 8 August. 



Habitat: Eared grebes in the Valley have been found primarily on large per- 

 manently flooded wetlands with extensive growths of emergent and sub- 

 merged aquatic vegetation. The St. Croix County nesting pair used a large 

 semipermanently flooded wetland. Vegetation of that wetland was charac- 

 terized by extensive beds of coontail surrounded by hardstem bulrush and 

 cattail. 



Western Grebe {Aechmophorus occidentalis) 

 Status: Casual migrant. 



Records: Western grebes have been observed twice in spring and once in fall 

 at Crex Meadows, Burnett County. The first record was 30 May 1974, and 

 the second 8 June 1976. The fall observation was on 26 August 1975. All 

 Crex Meadows records were obtained from the Phantom Lake flowage. J. O. 

 Evrard observed a single western grebe on the Fish Lake Wildhfe Area near 

 Grantsburg, Burnett County, on 3 June 1979. This bird was observed on 

 Crex Meadows on 11 June 1979 (Tessen 19796). This species has been 

 recorded three times in St. Croix County: 2 October 1976, two birds on Oak- 

 ridge Lake near New Richmond; 6 October 1967, three birds on Cedar Lake 

 near Star Prairie; and 12 October 1974, on Oakridge Lake. 



Pied-billed Grebe {Podilymhus podiceps) 

 Status: Regular migrant and nesting species. 



Migration: Common migrant throughout the Western Upland and Central 

 Plain, fairly common in the Northern Highland. Spring migrants arrive dur- 

 ing the last week of March (earUest— 9 March 1957, Burnett County). Peak 

 abundance occurs 20 April to 1 May. During peak migration, concentrations 

 of 75 to 100 individuals occur on several larger lakes in Chisago, Polk, and 

 Burnett counties. Fall migrants begin to concentrate in early September. 

 Peak fall abundance occurs during the second week of October and depar- 

 ture by 10 November (latest— 19 December 1974, Pierce County). 



