DEPARTING SUMMER VISITORS 173 
existence all down the ages must lead to the survival 
of types and forms best suited to their special 
environments. Birds best adapted and equipped for 
catching fish or for opening seed pods will get most 
fish or most seeds, will grow strongest, and in the 
inevitable struggle will drive off the less fit. But 
whence the colours and markings that appear with 
such wonderful regularity in various species i Each 
feather in its place and order will show markings 
that blend together into a pattern, and all will be 
faithfully and minutely repeated in every specimen. 
It is a problem as deep as that of the “ little flower of 
the crannied wall.” The Tanager does not moult 
his brilliant colours and bring forth a covering more 
suited to the advancing season. His feathers have 
changed their colour with the passing of the spirit 
that found expression in the love song warbled from 
the high limb of a dead but defiant pine. The same 
feathers that glowed scarlet in the spring sunshine 
reflect only a dull, insignificant, yellowish green. 
The most sociable and happy of our little transients 
is the Wild Canary or Thistle Bird, sometimes called 
the American Goldfinch. He seems quite as happy 
and glad as in the season of brilliant plumage and 
loud song. These little fellows are now hammering 
the seeds out of the Wild Sunflower heads and 
vigorously attacking the withered Asters. All seeds 
are acceptable, for they even pry open the cones 
