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NORTH AMERICAN FAUNA 73 



Migration: Common spring and fall migrant in the Western Upland and 

 Central Plain, uncommon and more local in the Northern Highland. Spring 

 migrants arrive in the Western Upland 5-10 April (earliest— 25 March 1963, 

 St. Croix County) and the Northern Highland 10-15 April. Peak spring 

 migration through the Valley occurs 15 April to 1 May. Peak fall migration 

 occurs 1-20 September and departure by 15 October. 



Nesting Season Distribution: Common nesting species in the Western 

 Upland and Central Plain, uncommon in the Northern Highland. Erickson 

 (1937), however, considered it abundant in Pine County. Breeding Bird 

 Survey data (Table 8) suggest that the vesper sparrow is the second most 

 abundant nesting sparrow in the Valley. Jackson (1943) reported that the 

 vesper sparrow was a common breeding bird throughout most of north- 

 western Wisconsin in 1919. 



Habitat: Characteristic nesting species of edge situations including fence- 

 rows adjoining agricultural fields and the border of retired cropland with 

 deciduous forest. Brushy highway rights-of-way and Old Field Communities 

 are regularly used in the Western Upland and Central Plain. Breeding 

 vesper sparrows in northern regions occur in open areas, brushy fields, or 

 occasionally in openings in Jack Pine Barrens. 



Lark Sparrow (Chondestes grammacus) 

 Status: Regular migrant and summer resident. 



Migration: Rare spring and fall migrant in the Western Upland and Central 

 Plain, absent from the Northern Highland except in the region near Grants- 

 burg, Burnett County. Spring migration dates occur during a narrow range 

 from 10-25 May. Fall migration dates range from 1-15 September. 



Nesting Season Distribution: The only evidence of possible breeding in the 

 Valley is available from the Union BBS transect in Burnett County. S. D. 

 Robbins found a small breeding "colony" of lark sparrows near Grant sburg 

 on 26 June 1975. Since then, up to five singing males have been recorded in 

 that location each year, but no nests of young have yet been found. Green 

 and Janssen (1975) showed that the breeding range of this sparrow in Minne- 

 sota includes Chisago, Washington, and southern Pine counties. S. D. Rob- 

 bins (personal communication) observed lark sparrows near Gushing, Polk 

 County, on 22 June 1977 and near North Hudson, St. Croix County, on 

 8 July 1965. During June 1977 I observed a group of five lark sparrows in 

 St. Croix County (Sec. 22, T. 30 N., R. 18 W.). The appearance of two of 

 these birds suggested that they were young of the year. Kemper (1973) 

 considered this species rare in Chippewa and Eau Claire counties, 120 km 

 east of the St. Croix County location. 



Habitat: Lark sparrows at the Burnett County location use an open area in 

 mixed bur oak- jack pine. The St. Croix County location was characterized 

 by the brushy edge of a Managed Grassland. 



