THE UNDERLYING IDEA 71 
the sparrow from his willingness to associate with 
man, and there are comparatively few birds with 
whom he must share them. Few birds select the im- 
mediate neighborhood of man’s home for their nests. 
They may live in the neighboring trees, they may 
haunt his orchard, but his house, for the most part, 
they decline to frequent. 
Still another quality which makes for success in 
this buccaneer is the willingness with which he will 
vary his food as occasion requires. It is a not infre- 
quent characteristic of the bird family that each spe- 
cies should have its own rather restricted diet. Birds 
are quite particular eaters, and many of them will 
come well nigh to starvation before they will use un- 
accustomed food. The sparrow, on the contrary, like 
man, eats almost anything he comes across that could 
reasonably be considered edible. He belongs to a 
group of birds which are structurally adapted to crack- 
ing the hard coats of seeds. This group of birds known 
as the finches is provided with the sort of bill familiar 
in the ordinary canary bird. It is short, heavy at the 
base, comes quickly to a point, and is firm and strong. 
With it the bird readily breaks through the hard outer 
coat of most seeds and feeds upon the rich cotyledons 
that are enclosed within. Nowhere in its entire struc- 
ture does the plant crowd so much nourishment in so 
little space as it does in the seeds. It is not by chance 
