rid of the eggs of the Cowbird. As the egg is too large to be thrust out, the Yellow 
Warbler commences a new nest above it. In one instance such reconstruction was twice 
effected ; thus forming a nest of three stories.” 
The clever method taken by the Yellow Warbler to baffle its persecutor indicates 
intelligence of a comparatively high order, since most birds are easily imposed upon and 
hatch and tend the greedy interloper to the ultimate destruction of their own offspring. 
The young Cowbird, once established, ts able, by reason of its superior size and strength, 
not only to appropriate most of the food brought by its foster parents, but entirely to 
dispossess its luckless companions by crowding them out of the nest, when, falling to 
the ground, they perish miserably. 
