44 



NORTH AMERICAN FAUNA 73 



during fall migration. Departure from the region occurs rapidly after 15 No- 

 vember; occasional stragglers linger along open areas of the St. Croix River 

 until 1 December. 



Nesting Season Distribution: There are six breeding records for the Valley: a 

 female with a brood of four on West Twin Lake, St. Croix County, 1968 (J. T. 

 Lokemoen); a female with a brood of four on East Twin Lake, St. Croix 

 County, 1975 (B. A. Moss); females with broods of five and six on the Gust 

 Waterfowl Production Area, St. Croix County, 1976 and 1977 (C. A. 

 Faanes); two broods of six and seven on Oakridge Lake during July 1976. 

 Elsewhere, occasional summering pairs have been observed in central Wash- 

 ington and southern Polk counties, although no broods have been observed. 

 At Crex Meadows, summering pairs are noted almost yearly, although the 

 only suggestion of nesting was a female acting "broody" on 16 June 1975 

 (S. D. Robbins, personal communication). 



Habitat: All redhead broods have been observed on large permanently 

 flooded wetlands where the dominant emergent vegetation consists of cat- 

 tail and river bulrush. 



Ring-necked Duck (Ay thy a collaris) 



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



Migration: Abundant migrant throughout the Valley. Spring migrants 

 arrive in the Western Upland about 15 March and the Northern Highland 

 1-5 April (earliest— 20 March 1950, Burnett County). Peak populations of 

 spring migrants occur 20 April to 1 May. Goddard (1975) found that ring- 

 necked ducks were the second most abundant spring migrant duck in St. 

 Croix County, making up 14.8% of the total waterfowl population and 32.8% 

 of the diving duck population. Departure from nonbreeding areas occurs by 

 20 May. 



Fall migrants begin to form flocks in the Northern Highland in mid-Sep- 

 tember and the first migrants reach the Western Upland about 25 Septem- 

 ber. Peak fall populations at Crex Meadows, Burnett County, usually occur 

 20-30 October and have included 5,000 (25 October 1967), 5,500 (25 October 

 1965), and 7,500 (26 October 1966). In the Western Upland, peak popula- 

 tions occur about 1 November and include up to 1,500 birds (B. A. Moss, 

 personal communication). Departure from the Valley occurs steadily 

 through November with stragglers occurring along the St. Croix River until 

 1 December. 



Nesting Season Distribution: Uncommon nesting species in the Western 

 Upland; fairly common in the Central Plain and Northern Highland, com- 

 mon at Crex Meadows. Breeding records have been obtained in all counties 

 except Pierce and the breeding range includes the area north of Marine-on- 

 St. Croix and New Richmond. 



Breeding waterfowl surveys at Crex Meadows reveal that the ring-necked 

 duck is the third most numerous nesting species (WDNR files). In St. Croix 

 and southern Polk counties, Peterson (1978) found that ring-necked ducks 

 constituted an insignificant percentage of the breeding population. How- 



