HOST RELATIONS OF PARASITIC COWBIRDS 209 



Yellow-green Vireo 



Vireo flavoviridis (Cassin) 



Marchant (1958, p. 384; 1960, p. 382, 584) has reported that the 

 Ecuadorean race of the shiny cowbu'd, M.h. aequatorialis, parasitizes 

 the local race {VJ. griseoharhatus) of this vireo in the Santa Elena 

 peninsula, southwestern Ecuador. He noted that 7 nests of this vireo 

 succeeded and 6 failed, and of these failures, 3 were due ostensibly 

 to parasitism by the cowbird. 



Ochre -fronted Vireo 



Hylophilus aurantiifrons Lawrence 



One subspecies of this vireo, H.a. saturatus, was previously recorded, 

 on the the basis of two records (Friedmann, 1938, p. 44), as a victim 

 of the shiny cowbird in Trinidad. Recently, Mr. R. Kreuger has 

 informed me that he possesses five parasitized sets of eggs of this 

 bird, all from Trinidad and all collected by Smooker, who had collected 

 the two earlier records. It seems probable that the first two are 

 included in the five cases. With such an increase in Imown instances 

 of parasitism, it now would appear that this vireo is locally a regular 

 host of the shiny cowbird. 



Cayenne Dacnis 



Dacnis cayana (Linnaeus) 



At Caroni Swamp, Trinidad, on July 18, 1932, G. D. Smooker 

 found a nest of this bird containing 2 eggs of the shiny cowbird and 

 1 of its own. The set is now in the collection of R. Kreuger of 

 Helsinki, to whom I am indebted for this record. The species was 

 not previously known as a cowbird host. The nominate race of the 

 host and the race M.b. minimus of the parasite are involved. 



Bicolored Ateleodacnis 



Aieleodacnis bicolor (Vieillot) 



Previously known, on the basis of a single record (Friedmann, 1938, 

 p. 44), as a host of the shiny cowbird in Trinidad, this little-known 

 species of honey-creeper now has been found to be parasitized also 

 in Surinam. Haverschmidt (in litt.) informs me that on February 

 28, 1953, in the vicinity of the Corentyne River near Nickeries, he 

 observed a recently fledged shiny cowbhd being attended and fed by 

 one of these honey-creepers. This observation adds it to the list of 

 hosts known to have reared the parasite; the former record was one 

 of eggs only. It should be pointed out that the Trinidad record may 

 not be wholly satisfactory when one considers the uncertain aspects 

 of our knowledge of the nesting habits of this honey-creeper. (See 

 Belcher and Smooker 1937, p. 520.) Both records here refer to the 

 nominate race of the host and to the small, northeastern race of the 

 parasite, M.b. minimus. 



