138 



NORTH AMERICAN FAUNA 73 



Habitat: Migrant magnolia warblers occupy a wide range of both deciduous 

 and coniferous habitats. This species is most frequently encountered during 

 migration in early successional stages of northern upland deciduous forest 

 and in Deciduous Clear Cuts. My observations of this warbler during the 

 breeding season have been confined to extensive stands of Black 

 Spruce-Tamarack Bog. This habitat type appears to be used extensively for 

 nesting within their normal breeding range in northern Minnesota and Wis- 

 consin. 



Cape May Warbler {Dendroica tigrina) 

 Status: Regular migrant, one summer record. 



Migration: Uncommon to rare migrant in the Western Upland and Central 

 Plain, uncommon to locally common migrant in the Northern Highland. 

 Spring migrants arrive in the Western Upland 5-10 May, reaching the 

 Northern Highland about 15 May. During spring migration. Cape May 

 warblers are most regularly observed 15-25 May and have departed by 

 1 June. Robbins (1973) provided the only summer record for the Valley, a 

 singing male 1.6 km north of Gordon, Douglas County, on 16 June 1971. Fall 

 migration begins in mid- August with first arrivals in the Central Plain about 

 20 August. During faU they are regularly encountered from 25 August to 

 10 September and depart by 25 September (latest— 29 September 1965, 

 Washington County). 



Habitat: Migrant Cape May warblers use various age classes of coniferous 

 habitats and early successional stage deciduous habitats. In residential 

 areas, this species is also attracted to blossoming apple trees and orna- 

 mental spruces. Robbins (1973) described the habitat of a group of nesting 

 Cape May warblers along the Brule River as black spruce. The area that 

 Robbins described is 8.0 km north of Solon Springs, Douglas County, and 

 within 4.8 km of the St. Croix River watershed. Because extensive stands of 

 similar black spruce habitat exist along the St. Croix near Solon Springs, I 

 would expect that additional birds could be located. However, to date I have 

 been unsuccessful in finding this warbler during the breeding season along 

 the St. Croix River. 



Black-throated Blue Warbler {Dendroica caerulescens) 

 Status: Regular migrant, occasional summer resident. 



Migration: Rare migrant throughout the VaUey. Most records are from 

 directly adjacent to the St. Croix River. Spring migrants arrive 5-10 May 

 (earliest— 2 May 1972, Washington County) and have departed by 25 May. 

 Fall records tend to indicate that this warbler occurs more commonly during 

 that period. Fall migrants arrive 30 August to 5 September. Records indi- 

 cate that peak fall numbers occur 15-25 September and departure by 

 30 September (latest-21 October 1961, Polk County). 



Nesting Season Distribution: The only evidence of summer residence is pro- 

 vided by Green and Janssen (1975) who reported the most southerly summer 



