76 U.S. NATIONAL MUSEUM BULLETIN 233 



on Swainson's thrush in Michigan, as reported by Swales (1893, 

 pp. 100-101). 



Veery 



Hylocichla fuscescens (Stephens) 



All three of the currently recognized races of the veery are para- 

 sitized by the brown-headed cowbird, two races of which, in turn, 

 are involved in the various records. The veery is a fairly common 

 victim, but the degree of frequency seems to vary considerably in 

 different parts of its range. The records, approximately 80 in num- 

 ber, are from southern Quebec (subspecies H.f. fuliginosa); 

 Ontario, Maine, Massachusetts, Connecticut, New York, Pennsyl- 

 vania, Ohio, and Illinois (the foregoing, H.f. fuscescens); Michigan, 

 Wisconsin, Minnesota, North Dakota, Manitoba, Saskatchewan, 

 Alberta, and British Columbia (the foregoing, H.f. salicicola). The 

 greatest frequency of cowbird parasitism has been reported from 

 Charlevoix County, Michigan, where Nickell (1942, pp. 99-108) 

 found that 16 out of 29 nests which were studied were parasitized. 

 Since then he has added other local instances. At Ithaca, New York, 

 in my own field work, 7 out of about 30 nests which were observed 

 contained cowbird eggs or young. As many as 5 cowbird eggs have 

 been found in one nest of this thrush. One such nest was found by 

 B. W. Cartwright near Winnipeg, Manitoba, June 18, 1932, contain- 

 ing a single egg of the host together with 5 cowbird eggs, which 

 appeared to have been laid by two different individuals. Another 

 case, reported by Schorger (1931, p. 39) from Bayfield County, 

 Wisconsin, contained 2 eggs of the thrush and 5 of the parasite. 



In southern Quebec, Terrill (1961, p. 5) reported 17 parasitized 

 nests out of a total of 128 nests examined. He found that the veery 

 was a very tolerant host; he never saw any evidence that it attempted 

 to eject or to bury the parasitic eggs. 



Eastern Bluebird 



Sialic sialis (Linnaeus) 



The eastern, nominate race of the bluebird is known to be para- 

 sitized by all thi-ee races of the brown-headed cowbird. Nowhere 

 is it a frequently used fosterer, but it is probably one of the most 

 often victimized of all hole-nesting birds, the most affected in this 

 regard being the prothonotary warbler. About 30 instances have 

 come to my attention, ranging from Quebec, Alassachusetts, Rhode 

 Island, Connecticut, New York, Pennsylvania, and West Virginia 

 westward to Ohio, Illinois, Michigan, Wisconsin, Iowa, Missouri, 

 Arkansas, Oklahoma, Texas, and Wyoming. Simmons (1925, p. 172) 

 lists the bluebird as a cowbird host in the area of Austin, Texas, 

 where the breeding form of the parasite is the small race ohscurus. 



