570 THE AMERICAN NATURALIST. 
neither of them could steady itself by holding on to a small 
branch, — at least, the younger one could not, and its sister 
could do so only for a short time, —while the oldest bird of this 
brood could perch well. Sparrow hawks usually build their 
nests in the hollows of old trees, but occasionally they utilize 
the abandoned nests of other species. 
