Dec. 15. The roof was not yet covered. Ice had formed on the pond, and house-building operations were at an end until the spring of 1922.
XV
THE MENTAL TRAITS OF BIRDS
In comparison with mammalian mentality, the avian mind is much more elementary and primitive. It is as far behind the average of the mammals as the minds of fishes are inferior to those of reptiles.
Instinct Prominent in Birds. The average bird is more a creature of instinct than of reason. Primarily it lives and moves by and through the knowledge that it has inherited, rather than by the observations it has made and the things it has thought out in its own head.
But let it not for one moment be supposed that the instinctive knowledge of the bird is of a mental quality inferior to that of the mammal. The difference is in kind only, not in degree. As a factor in self-preservation the keen and correct reasoning of the farm-land fox is in no sense superior to the wonderful instinct and prescience of the golden plover that, on a certain calendar day, or week, bids farewell to its comfortable breeding-grounds in the cold north beyond the arctic circle, rises high in the air and launches forth on its long and perilous migration flight of 8,000 miles to its winter resort in Argentina.
The Migrations of Birds. Volumes have been written on the migrations of birds. The subject is vast, and inexhaustable. It is perhaps the most wonderful of all the manifestations of avian intelligence. It is of interest chiefly to the birds of the temperate zone, whose summer homes and food supplies are for four months of the year buried under a mantle of snow and ice. All but a corporal's guard of the birds of the United States and Canada must go south every winter or perish from starvation and cold. It is a case of migrate or die. Many of the birds do not mind the cold of the northern winter—if it is dry; and if they could be fed in winter, many of them would remain with us throughout the year.
Consider the migratory habits of our own home favorites, and see what they reveal. After all else has been said, bird migration is the one unfathomable wonder of the avian world. Really, we know of it but little more than we know of the songs of the morning stars. We have learned when the birds start; we know that many of them fly far above the earth; we know where some of them land, and the bird calendars show approximately when they will return. And is not that really about all that we do know?
[Illustration with caption: MIGRATION OF THE GOLDEN PLOVER From
"Bird Migration,", by Dr. W. W. Cooke, U. S. Department of
Agriculture, 1915.]
What courage it must take, to start on the long, tiresome and dangerous journey! How do they know where to go, far into the heart of the South, to find rest, food and security? When and where do they stop on the way to feed? Vast areas are passed over without alighting; for many species never are seen in mid career. Why is it that the golden plover feels that it is worth while to fly from the arctic coast to Argentina?