HOST RELATIONS OF PARASITIC COWBIRDS 187 



They were collected in Costa Rica; at present they are in German 

 collections, one in the Schon wetter and two in the Domeier Collection. 

 The bronzed cowbird of Costa Rica is of the nominate subspecies. 



Rufous-sided Towhee 



Pipilo erythrophthalmus (Linnaeus) 



Bent (1958, p. 462) quoted a commmiication from Skutch to the 

 effect that on June 14, 1933, Skutch saw a recently fledged bronzed 

 cowbird attended by a pair of Guatemalan spotted towhees (P.e. 

 repetens) ; this took place in the Guatemalan highlands, at an elevation 

 of about 8,500 feet. The cowbird is of the nominate race, but it should 

 be mentioned that, in his account of the birds of Guatemala, Griscom 

 (1935, p. 387) stated that the bronzed cowbird has been noted only 

 in clearings in the eastern lowlands. The present record would seem 

 to extend its range well up into the highlands. This is the only 

 instance I know of the rufous-sided towhee as a host of the bronzed 

 cowbird. 



Brown Towhee 



Pipilo fuscus Swainson 



The brown towhee has been recorded as a victim of the bronzed 

 cowbird a few times — in Arizona and in the Distrito Federal, Mexico. 

 R. S. Crossin (in litt.) found the nest of a brown towhee (race PJ. 

 mesoleucus) containing one towhee egg about to hatch, one newly 

 hatched towhee, and one bronzed cowbird egg of about five days incu- 

 bation; the observation was on May 16, 1959, near Sabino Dam, 

 Sabino Canyon, Pima County, Arizona. Visher (1910, p. 210) found 

 this host victimized near Tucson, where he noted 2 young of the parasite 

 being raised by a pair of brown towhees. R. W. Dickerman (1960, 

 p. 473) found a nest of this species in Chapultepec Park, Mexico City, 

 containing 5 eggs of the bronzed cowbird and none of the towhee. 

 The brown towhee at that locality is P.f. fuscus; in Ai-izona it is the 

 race P.f. mesoleucus. The parasite is of the nominate race in Mexico 

 City and T.a. milleri in Arizona. 



Sclater's Towhee 

 Pipilo albicollis Sclater 



Four records of this towhee as a victim of the bronzed cowbird have 

 come to my notice: one parasitized set of eggs from Etla, Oaxaca, 

 May 20, 1912, now in the J. P. Norris collection; two similar sets also 

 from Oaxaca, now in the Chicago Natural History Museum. Mr. 

 J. Stuart Rowley has informed me that he recently found another 

 case in Oaxaca. The host involved is of the nominate race; the 

 parasite, of the race T.a. assimilis. 



