334 BULLETIN 197, UNITED STATES NATIONAL MUSEUM 



"Nuptial. — The number of wintering specimens available is not 

 sufficient to determine with any exactness how extensive the pre- 

 nuptial moult is. I have examined specimens in the American Mus- 

 eum taken in western Amazonia between 2 February and 3 April which 

 were undergoing a moult of the primaries. A prenuptial moult of the 

 primaries is an exception among oscine birds." 



Winter. — He says on this point: "That the winter home of the 

 species is in Amazonian Colombia, Ecuador, Peru and Bolivia, is, I 

 think well established." He gives a number of records on which this 

 statement is based. 



I might add here that I have collected from various sources the 

 measurements of 17 eggs, in addition to those given by Mr. Skutch. 

 These average 20.6 by 14.7 millimeters; the eggs showing the four 

 extremes measure 21.5 by 15.0, 19.9 by 15.3, 19.0 by 14.5, and 21.3 by 

 14.0 millimeters. 



Since the above was written, Richard F. Miller has sent me data on 

 two nests of the yellow-green vireo observed by him in San Luis Potosi 

 on June 20 and 21, 1942. Both nests were quite inaccessible, but the 

 birds were seen to alight upon them. The first was in a large tree 

 with beechlike bark and rhododendronlike leaves, on the bank of a 

 river in a wood ; it was about 45 feet up over the stream and suspended 

 from a horizontal fork at the end of a branch about 25 feet long. The 

 second was in an enormous deciduous tree, 5 feet thick, in a meadow 

 containing a few widely scattered trees and near a wood ; it was over 

 15 feet above ground on the lowest limb and suspended from a hori- 

 zontal fork at its end.] 



DISTRIBUTION 



Breeding range. — The breeding range of the yellow-green vireo is 

 from northern Mexico (southern Sonora, Nuevo Leon, and central 

 Tamaulipas) south to eastern Guatemala and western Costa Rica. 

 There is a single breeding record from extreme southern Texas, near 

 Harlingen, in June 1943. 



Winter range. — The winter home of this species is in the Amazonian 

 region of Colombia, Ecuador, Peru, and Bolivia. 



Casual records. — Besides having nested there once, this vireo has 

 been found three times in Cameron County, Tex. : Fort Brown, August 

 23, 1877 ; Brownsville, June 7, 1892 ; and Mission, September 19, 1937. 

 Also a specimen was collected at Godbout, Quebec, on May 13, 1883; 

 and another near Riverside, Calif., on September 29, 1887. 



\Egg dates. — Costa Rica : 23 records, March 27 to June 30 ; 13 rec- 

 ords. May 6 to June 3, indicating the height of the season. 



Mexico : 2 records, June 20 and 21. 



