102 U.S. NATIONAL MUSEUM BULLETIN 2 33 



The northwestern race, M.a. artemisiae, has been found to parasitize 

 the myrtle warbler in Alberta and Saskatchewan. T. E. Randall 

 informed me that on May 27, 1934, he found a nest at Boyle, Alberta, 

 containing 4 eggs of the warbler and 1 of the cowbird. At Winterburn, 

 Alberta, a set of 3 eggs of the warbler with 1 of the cowbird was 

 collected ; the set is now in the Rowan collection at the University of 

 Alberta. Godfrey (1950, p.79; 1952, p. 166) noted fledgling cowbirds 

 attended by myrtle warblers at Grimshaw, Alberta, and at Flatten 

 Lake, Saskatchewan. Gunn (1956, p. 88) noted that a pair of myrtle 

 warblers at Spirit Lake, Saskatchewan, raised 2 of their own young 

 and 1 cowbird. Street {in Houston and Street, 1959, p. 176) found 

 this warbler to be victimized at Nipawin, Saskatchewan. Bent (1953, 

 p. 250) records two Alberta records sent to him by A. D. Henderson. 

 It now appears that the molestation of the mj^rtle warbler occurs 

 regularly throughout its range without regard to the subspecies of the 

 parasite. 



All records refer to the typical race of the myrtle warbler. 



Audubon's Warbler 



Dendroica auduhoni (Townsend) 



This warbler is known as a cowbird victim on the basis of only 

 four instances. E. M. Tait (Friedmann, 1934, p. 36) found that it 

 was parasitized at Trout Creek Point, British Columbia. Cowan (in 

 litt.) wrote to me that a parasitized nest had been found at Lumby, 

 British Columbia. Rogers (1955, p. 392) recorded a similar instance 

 at Cromwell Island, Flathead Lake, Montana. Finally, an egg of 

 the brown-headed cowbird taken from a deserted nest of this warbler 

 at Mammoth Camp, Mono County, California, on July 3, 1922, was 

 sent to the Santa Barbara Aluseum of Natural History. All four 

 records involve the cowbird race artemisiae, but they refer to two 

 races of the host — auduhoni in British Columbia and California, and 

 memorahilis in Montana. 



Black-throated Gray Warbler 



Dendroica nigrescens (Townsend) 



The black-throated gray warbler is a species that has been studied 

 very little; correspondingly, its relations with the brown-headed cow- 

 bird are documented poorl3^ There are three pertinent observations. 

 Marshall (1957, p. 112) found this warbler to be a victim of the local 

 race of the cowbird, obscurus, in the pine-oak woodlands of southern 

 Arizona, and Bent (1958, p. 454) noted that Hanna had collected 

 a parasitized set of eggs in San Bernardino County, California. 

 Recently, T. D. Burleigh has informed me that at Oakley, Cassia 

 County, Idaho, on July 20, 1958, he noted a male black-throated 



