456 U. S. NATIONAL MUSEUM BULLETIN 211 



M. French Gilman (1914) shows a photograph of a hooded oriole's 

 nest containing two eggs of the bronzed cowbird and four eggs of the 

 dwarf cowbird, also another that held two eggs of the bronzed cowbird 

 and two of the oriole, both found near Sacaton, Ariz. 



Herbert Brandt tells me that he examined a nest of this oriole in 

 Sabino Canyon, Ariz., that held one egg of the oriole and six eggs of the 

 bronzed cowbird. 



George N. Lawrence (1874) quotes Col. A. J. Grayson as follows: 



On the 19th of May, 1868, whilst hunting in the woods near Magatlan, I dis- 

 covered a nest of the Bull-head Fly-catcher (Pitangus derbianus), which is a 

 common species in this region, and builds a large nest, dome-shaped, the entrance 

 being on the side. Whilst I was quietly looking at the nest (which was about 

 forty feet from the ground), I observed a female Red-eyed Cowbird among the 

 branches of the same tree looking very melancoly. Suddenly she darted towards 

 the nest, upon the side of which she perched, and immediately attempted to 

 enter, but the vigilance of the fly-catcher was too acute, and observing the intrusion 

 upon her sacred domicile, quickly attacked the Cowbird and drove her instantly 

 away. I soon after saw the same bird examining the nest of the Mazatlan Oriole 

 (Icterus pustulatus) , but as there had been no egg yet laid in the nest, it did not 

 seem to suit her, and she soon disappeared in the intricacies of the forests, leaving 

 me strongly impressed as to her intentions. 



In southern Arizona, we found eggs of the bronzed cowbird in nests 

 of Scott's oriole and the hepatic tanager. 



Eggs. — The eggs of the bronzed cowbird are indistinguishable from 

 those of the red-eyed cowbird, described under that form. The 

 measurements given by Bendire (1895) evidently include the eggs of 

 both forms. 



Plumages. — The molts and plumages of this western race are 

 similar to those of the eastern race, but the colors are somewhat paler 

 and grayer in the immature plumages. The young male of this race 

 is similar to the young female of involucratus, but decidedly paler. 

 The adult male has violet rump and upper tail coverts. 



Dickey and van Rossem (1938) write: 



Neither sex reaches maturity until the first postnuptial molt. One-year-old 

 males are variously intermediate in coloration between adult males and adult 

 females, but acquire more of the male coloration at the time of the prenuptial 

 molt in spring. One-year-old females are duller and less metallic than mature 

 ones and are also slightly smaller. The annual (postnuptial) molt of the adults 

 takes place in September and October. Adults as well as one-year-old birds have a 

 spring molt, limited in extent and consisting chiefly of the replacement of a rela- 

 tively few feathers about the interscapular region, breast and head. 



Colors of soft parts. — Adult males in winter: iris, brownish orange to orange- 

 brown; bill, tarsi, and feet, black. Adult males in summer: similar, but iris, scarlet 

 to crimson. Females (adult and birds of the year alike at all seasons) : iris, similar 

 to adult males in winter, but averaging paler; bill, tarsi, and feet, brownish or 

 plumbeous black. 



