BIRDS OF THE ST. CROIX RIVER VALLEY 



133 



Coniferous Forest, Black Spruce-Tamarack Bog, and white cedar com- 

 munities. 



Prothonotary Warbler (Protonotaria citrea) 

 Status: Regular migrant and nesting species. 



Migration: Rare migrant in the Western Upland; one record from the 

 Central Plain (7 May 1966, Chisago County) Observations of this warbler 

 are insufficient to determine patterns of spring and fall migration. Most 

 records appear to be birds on or near potential nesting territories. Spring mi- 

 grants are usually first recorded 10-15 May (earliest— 4 May 1974, Pierce 

 County). Records of fall migrants are even more irregular; the latest is 

 10 September 1975 (St. Croix County). Most observations of this bird during 

 migration periods have been restricted to areas along and adjacent to the St. 

 Croix River in Pierce, St. Croix, and Washington counties. 



Nesting Season Distribution: Very rare nesting species, apparently re- 

 stricted to the Western Upland. Maurer (1970) briefly described the observa- 

 tion of a nest near Marine-on-St. Croix (Washington County) containing one 

 young on 5 July 1970. On 10 July 1945, 11 male prothonotary warblers were 

 found on territory between Marine-on-St. Croix and Stillwater, and three 

 females were observed feeding near nests (Hubert 1945). On 28 June 1945, a 

 single male was observed along the St. Croix River near Osceola, Polk 

 County. Observations of territorial males along the lower reaches of the Kin- 

 nickinnic, Willow, and Apple rivers provide evidence of possible additional 

 breeding records. 



Habitat: The prothonotary warbler is restricted almost entirely to large 

 stands of mature Lowland Deciduous Forest dominated by cottonwood, 

 green ash, and American elm. The brief description of the habitat near the 

 nest Maurer observed suggests a mixture of willow and basswood. 



Worm-eating Warbler (Helmitheros vermivorus) 

 Status: Casual, three spring records. 



Records: S. D. Robbins heard and saw one male along Trout Brook Road 

 near Hudson, St. Croix County, on 18 May 1969 (Faanes and Goddard 1976). 

 Maurer (1969) described the observation of a worm-eating warbler in Wash- 

 ington County on 18 May 1969. I observed one near Trout Brook Road in St. 

 Croix County on 18 May 1980. This species has been recorded with in- 

 creasing frequency in central Minnesota and southern Wisconsin and may 

 become more regular in the lower reaches of the Valley. 



Golden-winged Warbler ( Vermivora chrysoptera) 

 Status: Regular migrant and nesting species. 



Migration: Uncommon migrant throughout the Valley. Spring migrants 

 arrive in the Western Upland 5-10 Ma\ . and reach the Northern Highland 



