HOST RELATIONS OF PARASITIC COWBIRDS 161 



Slate-colored Junco 



Junco hyemalis (Linnaeus) 



The slate-colored junco is an infrequently reported host; probably 

 it is molested very slightly b}^ the brown-headed cowbird. Eighteen 

 instances have come to my attention. Three races have been re- 

 corded as victims: cismontanus in British Columbia; carolinends in 

 Virginia and West Virginia; hyemalis in Alberta, Saskatchewan, On- 

 tario, Quebec, Nova Scotia, New York, Pennsylvania, and Ohio. 

 These records involve two races of the parasite : artemisiae from Sas- 

 katchewan to British Columbia and ater in all the other areas. Both 

 cismontanus and hyemalis have been known to rear young cowbirds. 



In the Peace River District of British Columbia, Cowan (1939, p. 

 59) found that no fewer than four out of five junco nests which were 

 observed were parasitized — evidence which suggests that in this 

 region the bird is a commoner host than it has been found to be else- 

 where. The Nova Scotia record is of interest as a far northeastern 

 report. Mills (1957, pp. 25-27) noted that E. C. Allen found a 

 fledgling cowbird attended and fed by juncos near Halifax, Nova 

 Scotia, on July 17, 1933. 



Terrill (1961, p. 10) made one observation which may imply a 

 greater frequency of parasitism than the actual records have indicated. 

 He found the junco to be a "very close sitter . . . not readily 

 flushed from its well-concealed nest, so that few nests are found. . . ." 



Oregon Junco 



Junco oreganus (Townsend) 



This junco has been recorded as a cowbird victim onl}?- a few times to 

 my knowledge. In British Columbia, Cowan (1939, p. 59) found a 

 parasitized nest in the Peace River district, and Schultz (1958, p. 

 435) reports that Davidson saw a young cowbird of the northwestern 

 race, M.a. artemisiae, attended by Oregon juncos at Victoria, British 

 Columbia. Still another report from that province, sent to me from 

 the files of the British Columbia Nest Records Scheme at the Univer- 

 sity of British Columbia, concerns a nest with 4 eggs of the junco and 

 1 of the cowbu'd, found 35 miles south of Vernon, Okanagan Lake, 

 June 17, 1959. The junco breeding in British Columbia is of the 

 race J.o. montanus. At Berkeley, California, Johnston (1960, p. 137) 

 observed a fledgling cowbird being attended and fed repeatedly by a 

 female Oregon junco (race pinosus). 



Chipping Sparrow 



Spizella passerina (Bechstein) 



The chipping sparrow is one of the commonest victims of the 

 brown-headed cowbird. Over 600 records have been noted from 



