BIRDS OF THE ST. CROIX RIVER VALLEY 



175 



Nesting Season Distribution: Fairly common and local nesting species in all 

 regions, probably most abundant in the Northern Highland (Table 8). Jack- 

 son (1943) reported that the clay-colored sparrow was a common nesting 

 species at Danbury (Burnett County) and Solon Springs (Douglas County) in 

 1919. Clay-colored sparrows apparently become semicolonial where habitat 

 is favorable. 



Habitat: Primarily a species of edge situations including brushy fields. Thiis 

 species becomes numerous in recently burned areas or where there are rela- 

 tively young conifer plantings. Commonly found associated with retired 

 agricultural fields and Old Field Community where coarse perennial weeds 

 have become estabUshed. In the Northern Highland, this species has re- 

 sponded favorably to intensive management for sharp-tailed grouse on 

 sandy soils. Nests are usually found in association with sweet fern vege- 

 tation in areas of restored native prairie. Nesting clay-colored sparrows near 

 the mouth of the Kinnickinic River in Pierce and Washington counties are 

 associated with brushy open areas in Southern Deciduous Forest. 



Field Sparrow {Spizella pusilla) 



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



Migration: Fairly common to common migrant throughout the Valley. 

 Locally distributed in heavily forested regions of the Northern Highland. 

 Spring migrants arrive in the Western Upland about 10-20 April and the 

 Northern Highland by 1 May. Peak spring migration through the Valley 

 occurs late April to 15 May. Fall migration begins in the northern regions in 

 late August and departure is by 15 September. Peak fall migration through 

 the lower Valley occurs during 15-25 September and departure by 15 Oc- 

 tober. 



Nesting Season Distribution: Fairly common and well-distributed nesting 

 species in the Western Upland and Central Plain. Rare (locally common) 

 nesting species in the Northern Highland. Bernard (1967) considered this 

 sparrow a rare summer visitor and possible resident in Douglas County. 

 Breeding Bird Survey data (Table 8) suggest that the field sparrow occurs 

 fairly regularly during the nesting season in southern Douglas County. 

 Roberts (1932) credited the removal of coniferous forest and replacement 

 with a deciduous forest type with the expansion of this sparrow northward 

 along the St. Croix River to southern Pine County. 



Winter: Three winter records for St. Croix County from the Afton CBC, 

 including single birds on 1 January 1971 and 1973, and three birds in one 

 group on 1 January 1978. It is not known if any of these birds survived the 

 winter. When the location of the 1978 birds was rechecked on 12 January 

 1978, the birds were not found. 



Habitat: Characteristic nesting species of the Old Field Community where it 

 is associated with early successional species including box elder, trembling 

 aspen, staghorn sumac, and chokecherry. Use is also made of well-estab- 

 Ushed growths of various coarse weeds in retired agricultural fields. During 

 early stages of development, field sparrows are regularly encountered in 



