BIRDS OF THE ST. CROIX RIVER VALLEY 



83 



census of breeding black terns in St. Croix County showed a decrease from 

 42 pairs in 1975 to 9 pairs in 1977 (Faanes 1979). 



Habitat: Black terns are a characteristic species of large seasonally and 

 semipermanently flooded wetlands that support an abundance of emergent 

 aquatic vegetation. Most nests that I have examined were on a floating 

 vegetation mat, usually composed of submerged plants and emergent plant 

 leaves. In the northern forested regions, black terns are less common as a 

 nesting species. In this region, large, acidic wetlands are most regularly used 

 for nesting. 



FAMILY COLUMBIDAE: Pigeons and Doves 



Rock Dove {Columba livia) 

 Status: Regular permanent resident. 



Distribution: An abundant permanent resident in cities, towns, and near 

 farm buildings. Uncommon to rare away from human habitation. 



Mourning Dove {Zenaida macroura) 



Status: Regular migrant, nesting species, and winter resident. 



Migration: Abundant migrant in the Western Upland and Central Plain, 

 uncommon and more local in the Northern Highland. Spring migrants arrive 

 in mid-March, reaching peak abundance 5-15 April. Fall migration begins 

 with flock formation among immatures in mid-August. Peak abundance 

 occurs between 15 September and 1 October, and most birds depart by 

 25 October. Several nestUngs that I banded in this region were recovered in 

 southern Texas by the end of September during the same year of banding. 



Nesting Season Distribution: The mourning dove is an abundant nesting 

 species in the Western Upland and Central Plain. In the Northern Highland, 

 mourning doves are uncommon to rare nesting birds. Mourning doves have 

 a rather long nesting season at this latitude; nest dates range from 18 April 

 to 20 September. 



Winter: A fairly common winter resident in the Western Upland, rare to 

 absent elsewhere. The CBC data indicate that the early winter distribution 

 is centered in St. Croix and Washington counties. 



Habitat: A characteristic edge species, occurring in largest densities in Pine 

 Plantations, shelterbelts, and fencerows. Occurs fairly commonly in orna- 

 mental coniferous trees planted in residential areas. 



Passenger Pigeon (Ec topis tes migratorius) 

 Status: Extinct. 



Records: The destruction of this species across North America has been well 

 documented. Passenger pigeons were a common nesting species in the 



