BIRDS OF THE ST. CROIX RIVER VALLEY 



99 



Migration: Uncommon to fairly common migrant throughout the Valley, 

 locally common along the lower reaches of the St. Croix River. Spring mi- 

 grants generally arrive about 1 May in the Western Upland and 5-10 May 

 in the Northern Highland. Peak abundance occurs 15-30 May. Fall migra- 

 tion begins in mid- August, reaching peak abundance by 1 September. Mi- 

 grants have departed the Northern Highland by 15 September and the 

 remainder of the region by 25 September. 



Nesting Season Distribution: Uncommon nesting species in the Western 

 Upland and Central Plain, fairly common to locally common in the Northern 

 Highland. Breeding Bird Survey data (Table 3) suggest a gradual increase in 

 breeding densities moving northward through the Valley. However, Jackson 

 (1942) recorded great crested flycatchers as "never more than two seen at a 

 locahty . . ."in the Northern Highland. Goddard (1972) found this flycatcher 

 to be among the 12 most numerous breeding birds along the Kinnickinnic 

 River Valley in Pierce County. Nesting has been confirmed only in St. Croix 

 County where I observed a nest along the Willow River on 10 June 1975. Al- 

 though only one nest has been confirmed, inferred nesting records have been 

 obtained in the remaining counties. 



Habitat: The great crested flycatcher is a forest species, generally asso- 

 caited with the upper canopy of medium-aged to mature deciduous forest. 

 The only confirmed nesting record was obtained from a mature Lowland 

 Deciduous Forest where cottonwood was the predominant tree species. 

 Pairs are commonly recorded in extensive stands of Northern Hardwood 

 Forest and in Southern Deciduous Forest. Use of residential habitats has 

 also been recorded. 



Eastern Phoebe {Sayornis phoebe) 

 Status: Regular migrant and nesting species. 



Migration: Fairly common migrant throughout the Valley. Eastern phoebes 

 are among the first passerines to return in the spring; the first migrants 

 arrive in the Western Upland 20-25 March. Although most observations 

 consist of pairs on breeding territories, a peak in spring migration is appar- 

 ent 15-25 April. Fall migration begins in mid- August and peak movements 

 occur 5-15 September. Late departure dates range from 1-5 October in the 

 Northern Highland to 20 October in the Western Upland. 



Nesting Season Distribution: Fairly common nesting species in all regions 

 and documented nesting records exist from each county. Breeding Bird 

 Survey data (Table 3) indicate a fairly evenly distributed breeding popu- 

 lation. Jackson (1942) considered the eastern phoebe to be a very common 

 breeding bird along the St. Croix River. Goddard (1972) reported a density 

 of 9.1 breeding pairs per 40 ha in the Kinnickinnic River Valley, Pierce 

 County. 



Habitat: Eastern phoebes are attracted to a variety of edge situations, pri- 

 marily woods-field border and streamside habitats. During the nesting 

 season, eastern phoebes are usually associated with bridges, culverts, or 

 other man-made structures, sheer cliffs, and rocky outcroppings. 



