130 



NORTH AMERICAN FAUNA 73 



Table 6. Mean number of vireos and warblers recorded on western Wis- 

 consin Breeding Bird Survey transects, 1966-78. 



Western 



Upland Central Plain Northern Highland 

 Species Hudson Dresser Loraine Union Minong 



Vireos 



Yellow-throated 



1.2 



1.7 



2.8 



3.8 



2.0 



SoHtary 



0.0 



0.0 



0.2 



0.0 



1.2 



Red-eyed 



3.6 



6.6 



21.3 



16.1 



41.2 



WarbHng 



6.1 



13.1 



10.7 



3.8 



5.4 



Warblers 













Black-and-white 



0.0 



<0.1 



1.3 



<0.1 



6.9 



Blue-winged 



<0.1 



0.0 



0.0 



0.0 



0.0 



Golden-winged 



0.0 



0.3 



5.1 



0.0 



2.5 



Nashville 



0.0 



<0.1 



1.4 



1.7 



20.2 



Yellow 



2.5 



5.8 



21.9 



1.6 



8.0 



MagnoHa 



0.0 



0.0 



0.0 



0.0 



<0.1 



Cape May 



0.0 



0.0 



0.0 



0.0 



<0.1 



Yellow-rumped 



0.0 



0.0 



0.0 



0.2 



1.9 



Black-throated green 



0.0 



0.0 



0.0 



0.0 



0.6 



Blackburnian 



0.0 



0.0 



0.0 



<0.1 



0.2 



Chestnut-sided 



0.3 



0.2 



5.2 



3.9 



29.8 



Pine 



0.0 



0.0 



0.3 



0.4 



3.8 



Ovenbird 



0.0 



0.5 



4.7 



23.7 



19.0 



Common yellowthroat 



7.9 



12.6 



36.2 



14.6 



36.2 



Mourning 



0.0 



<0.1 



1.2 



<0.1 



6.3 



Connecticut 



0.0 



0.0 



0.0 



1.7 



2.7 



Canada 



0.0 



0.0 



<0.1 



0.0 



1.7 



American redstart 



0.0 



0.6 



5.2 



0.3 



7.9 



Nesting Season Distribution: Documented evidence of nesting by this vireo 

 exists only for Douglas County, where I observed an adult incubating on 

 11 June 1977. This bird was found along the St. Croix River about 6.4 km 

 west of Gordon, Wisconsin. Although there is considerable evidence of 

 nesting in Burnett and Pine counties, neither nests or young have been ob- 

 served. Breeding Bird Survey data (Table 6) also suggest that nesting is pri- 

 marily restricted to the Northern Highland. 



Habitat: Solitary vireos are characteristic of Lowland Coniferous Forest. 

 Vegetation associated with the Douglas County nest site was Lowland 

 Coniferous Forest dominated by black spruce and white cedar adjacent to 

 the St. Croix River. Additional observations within the breeding range occur 

 in similar habitat or in Black Spruce-Tamarack Bogs. 



Red-eyed Vireo (Vireo olivaceus) 



Status: Regular migrant and nesting species. 



