NO. II DATA ON THE PARASITIC COWBIRDS — FRIEDMANN 3 



Bushtit 



Psaltriparus minimus (Townsend) 



On July 14, 1963, at Los Angeles, T. R. Howell examined a 

 deserted nest of a bushtit that contained a mummified carcass of 

 an almost fledged bushtit, part of a shell of a bushtit egg, and about 

 one-half of the shell of a cowbird egg (M. a. obscurus). The last had 

 a yellow crusty inner coating of dried yolk and presumably did not 

 hatch. 



Ruby-crowned kinglet 



Regulus calendula (Linnaeus) 



Another instance of cowbird parasitism on this infrequently used 

 host has been reported. At Virginia Lake, Mono County, California, 

 9,400 feet, a pair of these birds was seen feeding a fledged young 

 cowbird (race artemisiae) (Shepard, 1962, pp. 505-506). This is the 

 second time this host has been reported rearing the young of the 

 parasite. 



Mockingbird 



Mimius polyglottos (Linnaeus) 



Although the mockingbird had been reported as an infrequent 

 victim of the brown-headed cowbird in a number of areas, it was 

 never found to rear the young parasite. Recently Webster (1964) 

 reported that Dr. Pauline Jones found this host (race leucopterus) 

 rearing a young cowbird {obscurus) in southern Texas. 



Cedar waxwing 



Bomby cilia cedrorum Vieillot 



The cedar waxwing has been parasitized relatively infrequently, but 

 in July of two successive years, 1964 and 1965, four parasitized nests 

 were found in or near Waterloo County, Ontario, Canada, by Mr. 

 Robert Pickering. Each contained one egg of the brown-headed cow- 

 bird and four of the host. The unusual incidence of parasitism is seen 

 in proper perspective when we recall that in a fairly similar locality in 

 southern Quebec, Terrill found four parasitized nests (out of a total 

 of 329 waxwing nests examined) during a period of 50 years. Dr. 

 Johan Ottow told me of the new cases, which bring the total number 

 of records from 18 to 22. 



