898 U.S. NATIONAL MUSEITM BULLETIN 23 7 part 2 



breast with single dark central spot. * * * Young birds are finely 

 streaked on the breast and lack the central spot, but are otherwise 

 quite recognizable." 



Enemies. — H. Friedmann (1929) notes that "Both the eastern and 

 western forms of the Lark Sparrow are known to be victims of the 

 Cowbird." He considers the eastern race "an uncommon host," 

 for which he then had only three records, one from Oklahoma. Later 

 he (1934) records nine parasitized nests in Decatur County, Kans., 

 and for the western race notes that "Mi's. Nice (Birds of Oklahoma, 

 rev. ed., 1931, p. 183) records five parasitized nests (out of 23) in 

 Oklahoma." 



During the summer of 1957 at the Lake Texoma Biological Station, 

 several life history studies of birds were in progress. As it was felt 

 that fewer nests would be deserted if the cowbird population was 

 thinned out, a number of cowbirds were collected in the vicinity of 

 the station early in the season. During the summer I recorded only 

 three cases of cowbkd parasitism near the station. On June 7 a 

 cowbird laid in a lark sparrow's nest containing one egg; the parents 

 promptly deserted. On June 14 a cowbird laid in another lark spar- 

 row's nest containing three fresh eggs, probably an incomplete 

 clutch as the female had not yet started to incubate; she also deserted. 

 On July 6 I found a female lark sparrow incubating four of her 

 own eggs and one cowbird egg. The four lark sparrow eggs hatched 

 July 10, the cowbird egg on July 13. This suggests the lark sparrow 

 may be more apt to accept a cowbird egg after she has started to 

 incubate her own clutch. Later that month I saw a number of young 

 cowbirds out of the nest being fed by lark sparrows away from tlie 

 station. The lateness of these records also suggests that the lark 

 sparrows may accept cowbn-d eggs more readily late in the season, 

 after experiencing several nesting failures. 



Distribution 

 Eastern Lark Sparrow (C. g. grammacus) 



Range. — Minnesota, southern Michigan, southern Ontario, and 

 western New York south to southern Mexico and southern Florida. 



Breeding range. — The eastern lark sparrow breeds from north- 

 western and central Minnesota (Warren, Isanti County) , north central 

 Wisconsin (Dunn County, Kelley Brook), southern Michigan (Kent 

 and St. Clair counties), southern Ontario (Hyde Park, Toronto), 

 western New York (Monroe County), and central Pennsylvania 

 (Beaver, State College) south through eastern Nebraska (West Point) , 

 eastern Kansas and Oklahoma to northeastern Texas, Louisiana 

 (Bienville), central western Alabama (Greensboro), western and 



