302 
INSECTIVOROUS BIRDS. 
black. Legs and feet bluish-grey, the hind claw rather the largest. 
- — The female merely differs by having the black and white adjoin- 
ing the eye less pure and deep. 
VIREOS (or Warbling Flycatchers.) 
In these the bill is rather short, a little compressed, and furnished 
with bristles at its base ; the upper mandible curved at the extremity 
and strongly notched ; the lower is shorter, and recurved at tip. 
Nostrils, at the base of the bill, rounded. Tongue cartilaginous and 
cleft at the point. Tarsus longer than the middle toe. Wings 
rather acute ; the 2d or 3d primary longest. — Female resembling 
the male. The species more or less tinged with olive-green. 
These birds, in the early part of summer, live exclusive- 
ly on insects ; towards autumn they feed on small bitterish 
or astringent berries, the hard, indigestible parts of which 
are regurgitated by the bill, as with the Flycatchers. 
They live almost wholly in trees, rarely ever alighting on 
the ground. The voice is highly musical, and their song 
long continued. At the approach of winter they migrate 
to tropical climates. - — They are peculiar to America. 
Besides their other affinities, they are related to the true 
Orioles, in which the young and females are also olive- 
green : both build pendulous nests ; have similar colored 
eggs ; their song is not very different ; and the young 
of both mew somewhat like cats. 
YELLOW-THROATED YIREO. 
(Vireo flavifrons, Vieill. Bonap. Muscicapa sylvicola , Wilson, i. 
p. 117. pi. 7. fig. 3. Phil. Museum, No. 6661 ?)’ 
Sp. Charact. — Yellow-olive; throat, breast, frontlet, and line 
round the eye, yellow ; belly white ; wings with 2 white bands, 
and, as well as the tail, blackish. 
