THE SUMMER WARBLER. 69 
consists largely of aphides, grubs and larvae, which it picks out from the 
interstices of the bark of the trees, the crevices of the fences and from 
the edges of the lap-boards of the buildings. It catches insects, too, upon 
the wing, with a grace and dexterity equal to that of the fly-catchers, 
and frequents the currant bushes and ‘vegetable gardens in search of 
worms and the eggs of insect pests. Throughout the round of his ex- 
peditions he never forgets to sing; he cheers himself along if no one 
else. Especially when in the trees does he indulge in his sweetest notes. 
Throwing his whole bulk to the front, with mandibles thrown open and 
upward, the notes trip off his nimble tongue with a flourish that almost 
knocks him over, and he is away soon to reappear and repeat his jolly 
carol. 
A very prominent characteristic of the Summer Warbler, and one 
which has excited universal comment and admiration from those who 
are conversant with its habit, is the resolution it displays in refusing to 
incubate the alien eggs of the Cow-bird, by whom this bird is frequently 
victimized. Seemingly too indolent to speed to her own home, the female 
of the Cow Black-bird very frequently avails herself of the nests of other 
and smaller birds in which to deposit her eggs, thus ridding herself of 
the cares of incubation and provision for her helpless progeny. 
With persistent determination, however, the Summer Warbler re- 
fuses the additional burden, and with remarkable sagacity makes shift 
to “avoid the hateful imposition even to the length of sacrificing its 
own eggs and giving up its nest.” When disinclined to proceed to this 
extremity, it will rebuild a new structure immediately over and- upon 
the original one, burying beneath it the alien egg, and such of its own 
as may be therein, and proceed as it originally intended. Should a 
second trespass be committed on the new nest, it will frequently repeat 
