ch at home? Why is the yellow-shafted flicker
of the East replaced in the West by the red-shafted flicker? These
questions are more easily asked than answered. From the writer's present
home in eastern Kansas it is only six hundred miles to the foot of the
Rockies; yet the avi-fauna of eastern Kansas is much more like that of
the Eastern and New England States than that of the Colorado region.

Perhaps the reason is largely, if not chiefly, physiological. Evidently
there are birds that flourish best in a rare, dry atmosphere, while
others naturally thrive in an atmosphere that is denser and more humid.
The same is true of people. Many persons find the climate of Colorado
especially adapted to their needs; indeed, to certain classes of
invalids it is a veritable sanitarium. Others soon learn that it is
detrimental to their health. Mayhap the same laws obtain in the bird
realm.

The altitude of my home is eight hundred and eighty feet above
sea-level; that of Denver, Colorado, six thousand one hundred and sixty,
making a difference of over five thousand feet, which may account for
the absence of many eastern avian forms in the more elevated districts.
Some day the dissector of birds may find a real difference in the
physiological structure of the eastern and western meadow-larks. If so,
it is to be hoped he will at once publish his discoveries for the
satisfaction of all lovers of birds.

If one had time and opportunity, some intensely interesting experiments
might be tried. Suppose an eastern blue jay should be carried to the top
of Pike's Peak, or Gray's, and then set free, how would he fare? Would
the muscles and tendons of his wings have sufficient strength to bear
him up in the rarefied atmosphere? One may easily imagine that he would
go wabbling helplessly over the granite boulders, unable to lift himself
more than a few feet in the air, while the pipit and the leucosticte,
inured to the heights, would mount up to the sky and shout "Ha! ha!" in
good-natured raillery at the blue tenderfoot. And would the feathered
visitor feel a constriction in his chest and be compelled to gasp for
breath, as the human tourists invariably do? It is even doubtful whether
any eastern bird would be able to survive the changed meteorological
conditions, Nature having designed him for a different environment.

INTRODUCTION TO SOME SPECIES

It was night when I found lodgings in the picturesque village of
Manitou, nestling at