108 HOW HE IS MADE 
with feathers. Birds who live away up in the 
cold have feathers down on to the toes. 
On looking carefully at one of these bare 
legs, it will be seen that it is not smooth like a 
lead pencil. It is marked in a sort of pattern. 
Different species of birds show different patterns. 
Some look like the shingles on a roof ; others 
like little squares or plates ; and some are finer, 
like scales on a tiny fish. 
These marks help in arranging birds in the 
books, as I said the patterns of the feather tracts 
do also. That is, all who have the same pattern 
are said to be related. 
The legs of birds are not all of the same 
length for their size. Some who never go about 
on the ground, like hummingbirds, swallows, 
and swifts, have very short legs. Birds who 
walk and hop on the ground have them longer, 
and birds who wade in the water have the long- 
est of all. 

