220 NATURAL HISTORY OF THE FARM 
This is the age of birds. They outnumber, in species, all 
other air-breathing vertebrates put together. Doubtless, 
their ability to fly and thereby to find food arid to escape 
enemies has had much to do with this preponderence. Hardly 
any other living things have acquired such power of flight, 
and no others have established regular seasonal 
migrations between summer and winter homes. 
A hundred or more species may be found in any 
good locality in the course of a year—more than 
half of them, song-birds. A few are permanent 
residents; a few are winter visitors from the far 
north; many are transient visitors that winter 
south of us and summer north of us, and asub- 
stantial number, including all the song-birds that 
we value most highly, are summer residents. 
These return to us every spring and settle and 
build nests and sing and rear their broods. Who 
does not feel a thrill of pleasure at the return 
of the bluebird, that soft-voiced harbinger of 
spring? 
simple toes Wild birds they are, yet they do not mind our 
of bome- presence if we treat them well. And a number 
ing boxes 
forbirde, Of the most charming little birds will settle near 
us and remain with us year after year if we 
provide them suitable places for nest building, located in 
safe and congenial surroundings. 
It is a pleasant aspect of evolution to contemplate that the 
birds we like best—the birds that sing and that fashion beauti- 
ful nests and rear their young with most parental care—are the 
ones that have been and are most successful in the race of life. 
While a number of the smaller birds look much alike on 
first approach, each species has its distinguishing peculiarities 
that a little careful observation will reveal—peculiarities of 
color and attitude, of flight and of notes, of haunts and of 
