BIRDS OF THE ST. CROIX RIVER VALLEY 



143 



Blackpoll Warbler (Dendroica striata) 

 Status: Regular migrant. 



Migration: Common migrant throughout the Valley. Spring migrants arrive 

 in the Western Upland 5-10 May (earhest— 30 April 1967; 1 May 1969, 

 Washington County) and the Northern Highland 10-15 May. Peak spring 

 migration occurs 15-25 May and departure is by 30 May (latest— 2 June 

 1970, Washington County). Fall migrants arrive in the Northern Highland 

 10-15 August and reach the Western Upland 15-20 August. Peak fall 

 migration occurs 30 August to 20 September and departure 25-30 Sep- 

 tember. 



Habitat: Although both deciduous and coniferous forest habitats are regu- 

 larly used, this warbler is the most common in mature deciduous forest. 



Pine Warbler {Dendroica pinus) 



Status: Regular migrant and nesting species. 



Migration: Uncommon to rare migrant throughout the Valley. Jackson 

 (1943) found this warbler not as plentiful as anticipated in 1919. However, 

 they were considered "common" at Danbury, Burnett County, 27-30 May 

 1919. Spring migrants arrive in the Western Upland 1-5 May and the 

 Northern Highland 5-10 May. This species is most frequently encountered 

 10-20 May. Departure from nonbreeding areas occurs by 25 May. Fall 

 migration begins in the Northern Highland 10-15 August and the first birds 

 reach the Western Upland 20-30 August. This species is most frequently 

 encountered 1-15 September and they have departed by 1 October. 



Nesting Season Distribution: Uncommon breeding species in the Northern 

 Highland, rare and local in the Central Plain. Breeding Bird Survey data 

 (Table 6) also suggest that this species is in the Western Upland during the 

 nesting season. Although breeding season records exist for all areas except 

 Pierce and Washington counties, confirmed nest records exist only for Pine 

 County. Territorial birds were recorded in Chisago County during the sum- 

 mers of 1973-74 and 1976. The only location of regular occurrence in St. 

 Croix County is near Burkhardt (Sec. 3, T. 29 N., R. 19 W.). 



Habitat: Characteristic nesting species of remnant white pine forest. Al- 

 though regularly recorded in Jack Pine Barrens, Breeding Bird Survey data 

 for the Union transect (Burnett County) suggest that low densities occur in 

 that habitat. 



Palm Warbler {Dendroica palmarum) 



Status: Regular migrant, probable nesting species. 



Migration: Abundant migrant throughout the Valley, probably second only 

 to the yellow-rumped warbler in overall abundance. Spring migrants arrive 

 in the Western Upland 25 April to 1 May, reaching the Northern Highland 

 1-5 May. Peak migration occurs 5-15 May and departure by 25 May. A 

 singing male in Chisago County on 4 June 1968 was undoubtedly a very late 



