108 



NORTH AMERICAN FAUNA 73 



Table 5. Mean number of corvids, parids, wrens, mimids, and thrushes 

 recorded on western Wisconsin Breeding Bird Survey transects, 1966-78. 



Western 



Species group 



Upland 



Central Plain 



Northern Highland 



Hudson 



Dresser 



Loraine 



Union 



Minong 



Corvids 













Blue jay 



4.9 



9.0 



11.2 



29.0 



19.1 



Common raven 



0.0 



0.0 



0.5 



<0.1 



3.2 



Common crow 



ob.d 



30.2 



54.7 



28.6 



29.5 



Parids and nuthatches 













Black-capped chickadee 



0.4 



0.6 



2.4 



7.0 



8.2 



White-breasted nuthatch 



0.6 



1.8 



2.2 



1.0 



0.5 



Kea-breasted nuthatch 



0.0 



<0.1 



0.0 



0.2 



0.5 



Wrens 













House wren 



8.9 



10.4 



13.3 



14.8 



9.0 



W^inter wren 



U.U 



0.0 



0.0 



0.0 



0.1 



Long-billed marsh wren 



U.U 



0.2 



0.2 



0.0 



0.0 



Short-billed marsh wren 



Z.O 



3.7 



6.4 



0.0 



1.3 



iVlIIIllUs 













Gray catbird 



K o 

 O.Z 



8.8 



16.7 



8.0 



12.4 



Brown thrasher 



8.4 



9.1 



5.2 



5.9 



5.6 



Thrushes 













American robin 



30.5 



46.1 



30.6 



19.8 



26.9 



Wood thrush 



0.4 



0.6 



0.7 



0.8 



2.2 



Hermit thrush 



0.0 



0.0 



0.0 



1.4 



6.1 



Veery 



<0.1 



1.4 



11.2 



1.2 



27.1 



Eastern bluebird 



2.1 



3.8 



3.9 



6.7 



1.8 



Bird Survey data (Table 5) demonstrate a gradual increase in abundance 

 northward across the Valley. 



Winter: Blue jays are among the few conspicuous members of the winter avi- 

 fauna in the Valley. Populations vary considerably each winter because of 

 various environmental factors affecting habitat suitability and food supply. 

 Analysis of CBC data (Table 4) indicates that winter populations are largest 

 in the Western Upland region where the predominant habitat is Southern 

 Deciduous Forest. Winter populations in Jack Pine Barrens (Grantsburg 

 CBC) are also high. Lowest winter populations occur in the mixed decid- 

 uous-coniferous forest type of the Northern Highland. Largest CBC counts 

 include 597 (2 January 1976) and 485 (2 January 1977) on the Suburban St. 

 Paul CBC, and 509 (1 January 1970) on the Afton CBC. 



Habitat: Blue jays use a variety of habitats for nesting, including deciduous 

 and coniferous communities, edge situations, and various ornamental plant- 

 ings in residential areas. Highest breeding densities occur in northern conif- 

 erous communities including Jack Pine Barren and mixed deciduous-conif- 



