HOST RELATIONS OF PARASITIC COWBIRDS 211 



the information. The cowbird involved is the small northern race 

 M.b. minimus. 



Grace's Oriole 



Icterus grace-annae Cassiii 



Marchant (1960, p. 586) recently has added this oriole to the list 

 of hosts of the shiny cowbird in southwestern Ecuador. He found a 

 nest in March, 1958, containing five young birds, "three of which 

 later observations showed were cowbirds: one young oriole died in 

 the nest when more than seven days old and well-feathered, but I was 

 uncertain of the fate of the other. It would have been most excep- 

 tional if it had survived in such a heavily parasitized nest. Both 

 adult orioles were feeding the young. When empty, I found a pale 

 blue, very faintly spotted, unhatched egg m the nest, presumably 

 another cowbird egg, since those of the genus Icterus are bluish white, 

 more or less heavily marked with chocolate and brown." The race 

 of shiny cowbird involved is M.b. aequatorialis . 



Lesson's Oriole 



Icterus chrysater (Lesson) 



Dr. F. C. Lehman V. (in litt.) recently informed me that a nest of 

 this oriole containing a shiny cowbird 's egg was found at El Tambo, 

 Cauca, Colombia, m 1938. The cowbird there is of the race Al.b. 

 cabanisi; the oriole, I.e. giraudii. There are no previous records of 

 this oriole as a cowbird host. 



Black-throated Oriole 



Icterus nigrogularis (Hahn) 



This oriole was previously known as a victim of the Colombian race 

 of the shiny cowbird, M.b. cabanisii, and of the race Al.b. minimus in 

 Trinidad and in Dutch Guiana. It has since been reported in Vene- 

 zuela by Gines, Avelado, et al (1951, p. 303) as a host of the local 

 race M.b. venezuelensis. The Trinidad and Guiana records refer to 

 the local race of the oriole (I.n. trinitatis), the others to the nominate 

 subspecies. 



Orange-backed Oriole 



Icterus jamacaii croconotus (Wagler) 



Dr. C. J. Mariukelle informed me (m litt.) that he has hi his col- 

 lection a set of eggs of the orange-backed oriole with a shiny cowbird 

 egg which was collected in British Guiana. The cowbird is of the sub- 

 species M.b. minimus. I know of no other record for this host. 



Red-breasted Blackbird 



Leistes militaris (Linnaeus) 



The southern race L.m. superciliaris , previously (Friedmann, 1938, 

 p. 45) known from only two records, is apparently a frequent host of 



