HOST RELATIONS OF PARASITIC COWBIRDS 53 



Say's Phoebe 

 Sayornis saya (Bonaparte) 



Six instances of brown -headed cowbii'd parasitism on Say's plioebe 

 have been reported, five from Kansas and one from Oldahoma. All 

 refer to the nominate race of the host and of the parasite. Two parasit- 

 ized nests were found by Guy C. Love in Decatur County — one on 

 May 30, the other on June 19, 1915 — both of which were collected 

 and eventuallj^ were incorporated into the J. P. Norris collection. On 

 June 6, 1941, H. L. Heaton found another parasitized nest in the 

 same part of Kansas. The fourth record, Idndly sent to me by Dr. 

 R. F. Johnston, concerns a nest with 3 Say's phoebe eggs and 1 of the 

 cowbird, found at Concordia, Cloud County, May 13, 1951, by Dr. 

 J. W. Porter. The fifth record reported a parasitized nest collected 

 at Oberlin May 30, 1909, by L. R. Wolfe. The Oklahoma record was 

 collected in Pa^vnee County, June 18, 1921 ; it is now in the collections 

 of the Western Foundation of Vertebrate Zoology. 



Without further data it is not possible to evaluate this flycatcher 

 as a cowbird host; the paucity of records, however, is suggestive of 

 the probability that Say's phoebe is not of much importance to the 

 cowbird and that the latter, in turn, is not an important factor in the 

 economy of the former. 



Yellow-bellied Flycatcher 



Emjpidonax flaviventris (Baird and Baird) 



Rarely victimized or, at least, rarely reported as a cowbird victim, 

 the yellow-bellied flycatcher is in our catalog on the strength of three 

 parasitized nests found in Alberta — two by T. E. Randall and one 

 by A. D. Henderson. The cowbird in aU three cases is the subspecies 

 artemisiae. 



Acadian Flycatcher 



Empidonax virescens (Vieillot) 



In the more than 30 years since my first appraisal (1929, p. 209) 

 of this flycatcher as a cowbird victim, only a small amount of addi- 

 tional data has come to hght and these new records do not alter 

 significantly the earlier findings. The Acadian flycatcher is generally 

 an uncommon host though, at times and locally, it may be imposed 

 upon rather frequentl}^ by the parasite. In CarroU County, Indiana, 

 Everman (1889, p. 23) found it to be one of the chief hosts of the 

 cowbird; and in Pennsylvania, Jacobs (1924, pp. 52-54) noted 12 

 instances. I have heard of some 59 records, an increase of only 34 

 in the 30 or more years since ni}^ 1929 compilation; they range from 

 New England, New York, Pennsylvania, Maryland, and Virginia, 

 westward to Ohio, Indiana, Illinois, Michigan, and Kansas. In the 

 last-named state, Brandt (1947) described in considerable detail the 



