HOST RELATIONS OF PARASITIC COWBIRDS 103 



gray warbler feeding a fledgling cowbird; this record, on geographic 

 grounds, must refer to the cowbird race artemisiae. 



Black-throated Green Warbler 



Dendroica virens (Gmelin) 



This warbler appears to be a very infrequent victim of the brown- 

 headed cowbird. Only 15 definite records have been reported, five 

 from Michigan, two each from Ontario, Quebec, Maine, and New 

 York, and one each from Minnesota and Ohio. All the records refer 

 to the nominate race of both host and parasite. Bicknell (1882, p. 

 159), on the authority of John Burroughs, listed the black-throated 

 green warbler as a cowbird victim in the Catskill Mountains of New 

 York. A little to the northwest, at Ithaca, New York, on July 3, 

 1922, I watched a recently fledged cowbird being fed by one of these 

 warblers. Mendall (m Palmer, 1949, p. 515) found a parasitized nest 

 at South Thomaston, Knox County, Maine, on July 13, 1936. Swain 

 (1899a, p. 33) found several nests of this warbler in Maine, of which 

 one was parasitized by the brown-headed cowbird. In southern 

 Quebec, TerriU (1961, p. 7) reported two cases out of a total of 16 

 nests examined; in Ontario, Harrington found two cases near Wasaga 

 Beach, South Georgian Bay, which I reported in an earlier paper 

 (1938, p. 48). Wikerstrom (1953, p. 147) saw a pair of these warblers 

 feeding two recently fledged cowbirds at O'Reilly, St. Clair County, 

 Michigan, on July 12, 1953; Wallace (1945, p. 174) and Pitelka (1940) 

 recorded still other cases of cowbird parasitism on this species in 

 Michigan. Guttman (1956, p. 136) noted one of these warblers feed- 

 ing two recently fledged cowbirds in Clearwater County, Minnesota, 

 on August 7, 1955. The first naturalist to record the black-throated 

 green warbler as a cowbird host was Krider (1879, p. 51), who, un- 

 fortunately, gave no locality for his record. 



Golden-cheeked Warbler 

 Dendroica chrysoparia Sclater and Salvin 



The golden-cheeked warbler has a very hmited breeding range, com- 

 prising a few counties in south-central Texas, but there it has been 

 recorded as a victim of the small race of the brown-headed cowbird, 

 M.a. obscurus. In all, nine definite instances of parasitism have come 

 to my notice. These nine do not include a statement by Strong (1919, 

 p. 181), who noted a parasitized nest, supposedly of this species, col- 

 lected on June 6, 1894, at Fort Small, Arizona, -with 3 eggs of the 

 warbler and 1 of the cowbird. Since the golden-cheeked warbler is 

 not known to breed in Arizona, there seems to be a misidentification here. 

 In the J. P. Norris collection there were three parasitized sets of eggs 

 taken in Comal County, Texas. Three other instances — from the 



630590—63 8 



