264 BIRDS OF PENNSYLVANIA . 
subsists chiefly on insects, which he captures on the wing, or secures 
while gleaning among the branches and leaves. In the late summer 
and autumn months he feeds, more or less, on raspberries, mulberries, 
pokeberries and wild grapes. His white shirt-front is often soiled with 
the bright juices of the fruits on which he feeds. 
Vireo philadelphicus (Cass.). 
Philadelphia Vireo. 
Description. 
Length about 4.90; extent 8|; tail2* ; wing2*; tarsus about.64; bill, along culmen, 
.40. Very similar to gilvus, but bill is smaller and not nearly so stout as in latter 
bird; no spurious primary as in gilvus ; chin and belly white, rest of lower parts 
pale sulphur-yellow, brigheston throat and breast; above dull olive-green, grayish- 
blue on crown with faint greenish tint; rump brighter than back ; white line from 
base of maxilla over eye ; indistinct whitish spot below eye; blackish spot in front 
of eye. 
Habitat.— Eastern North America, breeding chiefly north of United States north 
to Hudson’s Bay ; south, in winter, to Costa Rica. 
The Philadelphia Yireo is a regular but rather rare spring and fall 
migrant, arriving here late in April or early in May, and after the 20th 
of May it is seldom seen in Pennsylvania until it migrates southward in 
September. Prof. August Kock, of Williamsport, informs me that he 
is under the impression that this bird breeds occasionally in the mount¬ 
ainous regions of Lycoming county; and Mr. T. L. Neff gives it in his 
list as a probable breeder in Cumberland county. This bird is found 
generally in woods about the borders of streams. The Philadelphia 
Yireo, although similar to the Warbling, can be recognized from the 
latter by its usually brighter under parts, and although it has a resem¬ 
blance to the White-eyed species, it has not, like the last named, whitish 
wing bars. Its song is very much the same as that of olivaceus. 
Vireo gilvus (Yieill.). 
Warbling Vireo. 
Description. 
Length about ; extent about 9; wing 2£ ; tail 2.20; tarsus .69 ; bill stout, very 
much like a Red-eyed Vireo, and from back part of nostril to end along culmen 
about .50 ; similar in color to philadelphicus , but upper parts are more grayish and 
paler ; general color of lower parts white ; sides, flanks and under tail-coverts, and 
part of breast tinged with pale-yellow ; the spurious first quill measures about five- 
eighths of an inch in length. 
Habitat.— North America in general, from the Fur countries to Mexico. 
The Warbling Yireo is found in Pennsylvania as a common summer 
resident from the last week in April until late in September; in the 
southern part of the state I have taken specimens as late as October 10. 
This delightful songster is rarely seen or heard in the depths of the 
