96 U.S. NATIONAL MUSEUM BULLETIN 233 



of the parasite by this host; the others were all egg records, collected 

 when they first were found. Other Ontario records were reported by 

 BailUe and Harrington (1937, p. 242) and by Snyder (1938, p. 203). 

 Macoun (1909, p. 614) listed another Canadian record, near Ottawa, 

 for June 1, 1899. All of these records refer to the eastern race, both 

 of the host and of the parasite. Cartwright (1931, p. 185) reported 

 a nest with 2 eggs of the warbler and 3 of the cowbird in Manitoba; 

 there the parasite is of the race artemisiae. 



In the Itasca State Park area of Minnesota, Hickey, Hofslund, and 

 Borchert (1955) found two instances of cowbird parasitism on this 

 warbler. 



Virginia's Warbler 



Vermivora virginiae (Baird) 



This species only recently has been found to be molested by the 

 brown-headed cowbird. A single record reports a nest seen by Cross 

 (1950, p. 138) near Daniels Park, Colorado, in July 1949. Originally, 

 when first found by Niedrach, the nest contained several eggs of the 

 warbler and 1 of the cowbird (subspecies artemisiae), but when 

 Cross was shown the nest on July 13, it contained only a well-grown 

 young cowbird and a single, weak, little warbler. This is the same 

 instance as the case mentioned by Bent (1953, p. 124). 



Since the altitudinal range of Virginia's warbler largely is above 

 that of the cowbird, such general allopatry probably reduces the 

 incidence of parasitism on this host. 



Lucy's Warbler 

 Vermivora luciae (Cooper) 



The published data on Lucy's warbler indicate that, while there 

 are very few records of cowbird parasitism on the species, locally this 

 warbler may be imposed upon rather frequently. In the report on a 

 collection of birds from Arizona, Brewster (1882, p. 85) mentions a 

 young Lucy's warbler which was taken from a nest that also held a 

 young cowbird (subspecies ohscurus). Bendire (1895, p. 442) lists 

 this warbler as a cowbird host — probably on the basis of Brewster's 

 record. For a long time this was all that was laiown until Dawson 

 (1923, p. 458) listed three cases in California and referred to the 

 cowbird as a prominent enemy of this species. "Sometimes the 

 warblers are able to entrench themselves behind apertures so narrow 

 that the Cowbird cannot get in; and once we saw the Cowbird's 

 foundling resting unharmed, but also harmless, upon the doorstep' 

 not less than two inches distant from the warbler's eggs. Another 

 nest, more exposed, contained three eggs of the arch enemy, and had 

 been deserted by the troubled owners." More recently. Bull (1958, 

 p. 394) observed a fledgling dwarf cowbird being fed by Lucy's warbler 



