HOST RELATIONS OF PARASITIC COWBIRDS 83 



now in the Cruttenden collection, Quincy, Illinois. The records from 

 Oklahoma northward all refer to the host subspecies V.g. novehoracensis 

 and all involve the nominate race of the parasite. 



Since most of the records are based on eggs found in nests, the fact 

 should be pointed out that the white-eyed vireo has been known to 

 rear young cowbirds. Such was observed by Stone (1937, p. 877) on 

 three occasions at Cape May, New Jersey. In one of these instances 

 the pair of vireos was feeding two young cowbirds. 



Hutton's Vireo 



Vireo huttoni Cassin 



Hutton's vu*eo seldom is reported as a victim. Eight records have 

 come to my attention, six from California, involving the nominate 

 race of the host, and one each from Texas and New Mexico, involving 

 the race stephensi From California, Hanna (1928, p. 161) listed one 

 nest containing 2 cowbird eggs in the San Bernardino Valley and 

 another (1938) in Kiverside County; M. C. Badger informed me that 

 he had found a parasitized nest at Santa Paula, and H. W. Carriger 

 wrote to me that he had found two more cases near Oakland (in one 

 of the latter the nest contained a large young cowbird, almost ready 

 to leave); Grinnell and Wythe (1927, p. 104) recorded Hutton's vireo 

 as a cowbird victim in Cahfornia on the basis of a parasite nestling 

 taken from a nest between Niles and Irvington, June 15, 1923, by 

 H. V. LaJeunesse. From New Mexico, Mitchell (1898, p. 309) noted 

 stephensi as a cowbird victim in San Miguel County; in my first 

 account (1929, p. 189) I rejected this record on the basis of the local- 

 ity, which is considerably north of the known range of the vireo, but 

 later I noticed that Ridgway and others had accepted it; the A.O.U. 

 Check-list, however, still includes only southern New Mexico in its 

 range. From Texas, Fred F. Nye, Jr., \vrote me that on May 22, 

 1951, nine miles west of Hot Springs, Brewster County, he found a 

 nest of stephensi containing 4 eggs of its own and 1 of the dwarf race 

 of the cowbird. The California records also refer to the small race 

 of the parasite, but the New Mexico report involves the nominate 

 race, M.a. ater. 



Dwarf Vireo 



Vireo nanus Nelson 



Previously unknown as a cowbird host, this vireo now may be 

 added to the list of victims of the dwarf race of the parasite. In the 

 Moore Collection, Occidental College, there is a set of 4 eggs of the 

 vireo and 2 of the cowbird, taken on June 17, 1943, five miles north- 

 east of Irapucto, Guanajuato, Mexico. 



