North
American birds that exhibits such depravity.

[Illustration: The Greedy Young Cowbird]

All other birds display great willingness to attend to their home
duties, and often give evidence of keen delight while so engaged. One
of the most exquisite and dainty forms of bird life found in the United
States is the little Blue-gray Gnatcatcher. When occupied in building
the nest, which is usually saddled on the limb of some forest tree, the
birds call to each other constantly; and even after the eggs are laid
there is no attempt to restrain their expressions of happiness. Unlike
the Crow and Jay, that sometimes appropriate the nests of other birds,
these little creatures have no sins to answer for to their neighbours.
One of the most pleasing sights I {60} have witnessed was a male
Gnatcatcher that had relieved his mate at the nest. He was sitting on
the eggs and, with head thrown back, sang with all his might,
apparently unconscious of the evil which such gaiety might bring upon
his household.

{61}

CHAPTER IV

THE MIGRATION OF BIRDS

There is something fascinating about the word migration. It sends our
minds back to the dim stories of tribal movements carved on the rocks
by men who wrought in the dawn of history. We wonder at the compelling
force that drove our ancestors through the forests of northern Germany,
or caused the Aztecs to cross the Mexican deserts. It calls to
something in our blood, for even the most stolid must at times hearken
to the Pied Piper and with Kipling feel that "On the other side the
world we're overdue."

Man is not alone the possessor of the migrating passion. Menhaden, in
vast schools, sweep along our Atlantic Coast in their season. From
unknown regions of the ocean herring and salmon return to {62} the
streams of their nativity when the spirit of migration sweeps over the
shoals into the abysmal depths. There are butterflies that in
companies rise from mud puddles beside the road and go dancing away to
the South in autumn. The caribou, in long streams, come southward over
the barrens of Labrador when the word is passed, and even squirrels,
over extended regions, have been known to migrate en masse for hundreds
of miles. There is, however, no phase of the life of birds which is
quite so distinctive. The extent and duration of their migrations are
among the most wonderful phenomena of the natural world.

Ornithologists have gathered much information regarding