156 U.S. NATIONAL MUSEUM BULLETIN 23 3 



actual records are still few in number, the fact appears that in suitable 

 localities this bird may be a fairly common victim. In the Red River 

 valley, Kittam County, Minnesota, P. B. Peabody (1901, pp. 131-132) 

 found 14 nests, of which 4 were parasitized; 3 of them contained 

 a single cowbird egg apiece in addition to eggs of the host, and 1 

 held a half-grown cowbird and 2 addled eggs of the sparrow. In 

 the National Museum of Canada there is a parasitized set of eggs of 

 this sparrow taken at Crane Lake, Saskatchewan, in 1895 by Wm. 

 Spreadborough. Many jesirs later Ferry (1910, pp. 199-200) also 

 found that LeConte's sparrow was parasitized in Saskatchewan, and 

 A. D. Henderson informed me that he has noted this in Alberta as 

 well. Two races of the parasite are involved in these records, ater in 

 Minnesota, and artemisiae in Saskatchewan and Alberta. 



Henslow's Sparrow 



Passerherbulus henslowii (Audubon) 



Henslow's sparrow is a bird of which relatively little is known as far 

 as its relations with the brown-headed cowbird are concerned. Only a 

 few records have come to my attention. Hathaway (1913, p. 555) 

 found a parasitized nest in Rhode Island on May 28, 1911. E. J. 

 Court informed me that, out of 7 nests found in southern Mary- 

 land in 1932, 2 contained eggs of the cowbird, and that, out of about 

 15 nests found in previous years, several had been victimized. He 

 considered Henslow's sparrow a locally common host. The late J. P. 

 Norris wi'ote me that he had a set with a cowbird's egg, collected by 

 Court in Maryland on May 28, 1917. This probably is one of the 

 "several" referred to by Court. Stewart and Robbins (1958, p. 329) 

 mentioned that they had learned of five cases of cowbird parasitism on 

 this sparrow in Maryland. These five are probably also among those 

 found by Mr. Court. Hicks (1934, pp. 385-386) noted a parasitized 

 nest in Franklin County, Ohio. In Michigan, Olsen (1931, p. 482) 

 reported a parasitized nest found by Walkinshaw near Battle Creek. 

 Neither Hyde (1939) nor Sutton (1959, p. 150) found any evidence of 

 cowbird parasitism on Henslow's sparrow m their studies in Michigan, 

 which suggests that there this bird is only an occasional victim of the 

 cowbird. At Hegewisch, lUinois, on June 19, 1932, G. J. Suthard 

 collected a parasitized set of this sparrow's eggs. 



The Michigan, Illinois, and Ohio records refer to the western, typical 

 race of the sparrow, while the Rhode Island and Maryland instances 

 are of the eastern race, susurrans. The cowbird in all cases is typical 

 ater. 



In spite of Court's experience in AIaryland,it is not possible, except 

 locally, to consider Henslow's sparrow as a frequent host of the parasite. 

 Because of the relative scarcity and rather "spotty" local distribution 



