150 THE STORY OF THE BIRDS. 
cuts a bung-shaped piece out of the side of some 
cavity ; the woodpecker rarely uses a knothole fora 
beginning ; but the nuthatch (European) may plaster 
up with mud a (too 
large) natural opening 
or (American) enlarge 
one to suit. 
Out the other way, beyond 
the owls, runs another group of 
birds that are mostly insect eat- 
ers, flying by night usually, as 
the whip-poor-will, night hawks, etc. Some of the 
lower forms, like the owls, eat mice, but normally 
they are all provided with broad deep gapes, and 
some have hairlike feathers on each side to broaden 

The head of nuthatech. 
their aim in catching flying things in the gloom. 
Close akin to these are the swifts, with similar 
habits by day, and out from these, with similar wings, 
comes the hummingbirds. These get a mixed diet 
of insects and honey, and doubtless got their hum- 
ming habits because flowers were too weak for them 
to perch upon. In them the beak, like that of the 
Apteryx, has gone from the widest in their ancestors 
near the swifts to the slimmest known in Nature, so 
as to pick out the gnat; and the tongue has grown 
long and fringe-tipped to lap up the nectar, and is 
thin and membranous on the edge that it may be 
rolled into tubes to absorb it. 
Other members of. this Picarian group feed upon 
fruits and small animals, and have various interesting 
habits. The kingfishers, as we know them, dart 
