370 BULLETIN 19 7, UNITED STATES NATIONAL MUSEUM 



we have attributed to the warbling vireo. The side of the head, 

 marked only by a slight paleness above the eye, has an expression of 

 bland innocence; the delicate coloring of the plumage, with no spot 

 of ornament to set it off, gives an air of quiet refinement, like the 

 bird's song; and the diminutive bill gives the bird a youthful 

 appearance. 



Enemies. — Herbert Friedmann (1929) says of the relation of the 

 cowbird to tlie warbling vireo: "A very common victim. * * * 

 Eaton lists the Warbling Vireo as one of the commonest molothrine 

 victims in New York State, and I have numerous records from other 

 parts of the country. * * * All together over forty records have 

 come to my notice. In common with the other species of its family, 

 this Vireo normally makes no attempt to rid herself of the parasitic 

 eggs." In recent year the warbling vireo has probably suffered more 

 from the spraying of the shade trees with poison than from the natural 

 enemies that commonly beset small arboreal birds. Their nests have 

 been imperiled by the high-pressure spraying that rocks the elm 

 branches at the vital points of the birds' summer distribution, the road- 

 side trees of our country towns. 



Whiter.— Dowfildi K. Dickey and A. J. van Rossem (1938) speak 

 of the bird on its winter quarters : 



The winter home of the eastern warbling vireo can now be stated to be in 

 the foothills of El Salvador and adjacent parts of Central America. * • * 

 On Mt. Cacajniatique in late November and in December, 1925, warbling vireos 

 were abundant at 2,500 feet elevation, all through the berry-bearing trees which 

 provided shade for the coffee groves. From there up to the oak- and pine-covered 

 summit of the mountain (about 4,000 feet) they were also very numerous. 

 In February and March, 1926, both on Volcfln de Conchagua and Volcfin de San 

 Miguel numbers were observed in similar environments at from 2,500 to 3,500 

 feet, but mucli less commonly than in the interior. At Clulata in April, 1927, 

 warbling vireos were migrating and were usually in pairs. 



Ludlow Griscom (1932) writes: "It is apparently quite common 

 and generally distributed in Guatemala in winter, arriving principally 

 in October, the earliest date being September 28, 1926." 



DISTKIBUTION 



Range. — Canada to El Salvador. 



Breeding range. — The warbling vireo breeds north to northern 

 British Columbia (Atlin, Fort Halkett, and Fort Nelson) ; south- 

 western Ma(;kenzie (Wrigley, Simpson, Providence, and Resolution) ; 

 northeastern Alberta (Chippewyan and McMurray) ; central Sas- 

 katchewan (Wingard and Prince Albert) ; southern Manitoba (Duck 

 Mountain, Lake St. Martin, and Selkirk ; probably to Norway House) ; 

 southern Ontario (Port Arthur, Lake Nipissing, and Ottawa) ; 

 southern Quebec (Montreal and Quebec) ; southern New Brunswick 



