HOST RELATIONS OF PARASITIC COWBIRDS 157 



of the sparrow and the general abundance of the cowbird, it appears 

 that the former is less important in the economy of the parasite 

 than the latter is in that of the host. 



Sharp-tailed Sparrow 



Ammospiza caudacuta (Gmelin) 



The race nelsoni of this sparrow is included in the present survey on 

 the folloAving basis. Many years ago the late P. B. Peabody v/rote me 

 that he remembered very clearly that one of his associates once found a 

 cowbird egg in a nest of Nelson's sharp-tailed sparrow. Peabody had 

 no wa}" of getting the exact data on this occurrence. No one else smce 

 has reported a case of cowbird parasitism on this species. It would 

 seem, from the fact that the sharp-tail is a marsh bh'd, that probably it 

 is usually unmolested by the parasite. 



Seaside Sparrow 



Ammospiza maritima (Wilson) 



The seaside sparrow is an unusual and rarel}^ imposed upon victim 

 of the brown-headed cowbird. The latter ordinarily does not inhabit 

 bracldsh or salt water marshes, where this sparrow lives, and, as 

 a result, it rarely would have a chance to parasitize the bird. There is 

 only a single record for this sparrow (nominate race). Bagg and 

 Eliot (1937, p. 634, ftn.) stated that the seaside sparrow was recorded 

 as a fosterer of the cowbird at Martha's Vinej'ard by ]\Irs. Seth 

 Wakeman. In response to my inquiry, Mrs. Wakeman informed me 

 that the record referred to a fledged cowbird being fed and attended 

 by a seaside sparrow. No young sparrows were observed with them. 



Vesper Sparrow 

 Pooecetes gramineus (Gmelin) 



The vesper sparrow is a fairly frequent victim of the brown-headed 

 cowbird. About 70 records have been noted, involving two races of 

 the sparrow, gramineus and confinis, and all three races of the cowbird. 

 These records come frojn the following areas: Alberta, British Col- 

 umbia, Quebec, and Saskatchewan in Canada; Colorado, the District 

 of Columbia, Idaho, Illinois, Indiana, Iowa, Kentucky, ^Maryland, 

 Michigan, Minnesota, Montana, Nebraska, New York, Ohio, Texas, 

 Washington, and Wyoming in the United States. The race gramineus 

 is parasitized by ater; confinis, by artemisiae and obscurus. In no 

 locale is the vesper sparrow one of the commonest fosterers although 

 Eaton (1914, p. 227) has listed it as such in New York. In Ohio, 

 Hicks (1934) found 112 nests, of which 9 were parasitized; in southern 

 Quebec, Terrill (1961, p. 10) found 74 nests, of which 3 had cowbird 

 eggs. There is no need to repeat here the various records of geo- 



