102 HOW HE IS MADE 
eat leaves, so he shot a few and found them 
stuffed with small caterpillars. Then he looked 
at the plants and found many more caterpillars, 
each in the curled-up end of a leaf. The in- 
sects could not be seen, yet the birds, while fly- 
ing over, no doubt saw the curled leaves and 
knew they were there. 
Such eyes must be of great use in helping 
birds to find their food, and to avoid their ene- 
mies. But think what giants we must look to 
them! It is no wonder they are afraid of us. 
Perhaps even more useful to a bird than his 
eyes are his ears, though they are so nicely cov- 
ered up by the feathers that we cannot see 
them. The tufts of feathers that stand up on 
some owls’ heads, and are called ears, are not 
ears at all, but merely decorations, like the 
crests of some birds and the long tail feathers of 
others. 
But because they cannot be seen, we must not 
think birds have no ears; they have very good 
ones indeed. They can hear much better than 
we can. 
Every one has seen a robin run over the grass 
and turn his head one side to listen. It is sup- 
posed that he hears the earthworm move under 
the sod, and if he is watched, he will often be 
seen to pull the worm from that very spot. 
