Geologically considered, the migration of birds had its origin in the beginning of the Post-Tertiary period of our globe’s history. Prior to the Glacial Epoch there was no migratory instinct among the feathered tribes of the earth’s fauna for the simple reason that there was no necessity for such a change of habitat.

Thus the annual recurrence of this phenomenon has been going on not since the creation, as many suppose, but for units of ages whose lapse can be reckoned only by millenniums of calendar years. It is not the time and place here to discuss the means by which this length of time can be even approximately determined, but there are certain inferences and conclusions which are well endorsed by scientific research.

For our present purpose it is quite sufficient to say that the Glacial Epoch wholly changed the climatic relations of the polar and middle latitude regions of our globe. From the semitropical conditions which once perennially existed there, these regions have since and for ages been subject to the intense cold which now periodically prevails within those limits.

There is a growing conviction among geologists that the intense cold of the Glacial Epoch was caused by a change in the eccentricity of the earth’s orbit. If this be true, then the “Great Winter” of astronomers was reigning in all its severity 210,000 years ago.

The wild goose, his near relatives, the brant and swan, and other aquatic feathered races, made their appearance on the fifth day of creation. “And God said, Let the waters bring forth abundantly the moving creature that hath life, and fowl that may fly above the earth in the open firmament of heaven.”

Now this fifth day of creation very nearly corresponds to the Triassic and Jurassic periods of Mesozoic Time in Geology.

Although “every winged fowl after his kind” is included in the bird category of this creative act, it has been thought, and for good reasons, that the more highly organized birds other than the aquatic tribes, did not make their appearance till the sixth day of the Mosaic account, which would be exactly represented by the Tertiary Period of Cenozoic Time. According to this view, then, the wild goose is an older denizen of our world than the smaller birds of passage which make their home on the land only.

But Geology fills up many niches and supplies many details left blank in the first chapter of Genesis. It is now one of the firmly established tenets among geologists that between the Mesozoic and Cenozoic times there came a tremendous disturbance in the earth’s crust.

In his “Story of the Earth,” Dr. J. Dorman Steele says, “The Mesozoic time, like the Palaeozoic, was closed by mighty upheavals. The conditions of life were changed. All the Mesozoic types disappeared; hardly any species survived the shock.” A few individuals did survive, however, and among them was our venerable friend, the wild goose.

Having now finished the prefatory portion of our story, the reader will be better able to understand what may follow.

There is something wonderful, a conception, indeed, which smacks little short of the sublime in contemplating the protracted journeyings of the larger aquatic birds of passage. Especially is this true of the American wild goose, the brant and the swan. The brant is the wild goose of Great Britain and continental Europe; a much smaller bird than his American relative; and its migrations are of comparatively short range.

The European domesticated swan, remains, of course, the year round in the country of his adoption.

Not so, however, with the American goose and swan. Both the former, Anseres hyperboreas, and the latter, Cygnus buccinator, rear their young in the Arctic regions and spend the succeeding winter with their offspring in the Gulf States and Central America.

Think of these magnificent birds, those on the Pacific coast flying from the shores of the Arctic ocean in northern Alaska and British America, crossing the Rocky Mountains, and, after a journey of four or five thousand miles, complacently settling down in Texas, Mexico, Yucutan, or Nicaragua, as the experienced leaders may determine. Then turn to those on the Atlantic side of the continent and watch them as they leave the Baffin’s Bay country, cross the great lakes and the Appalachian mountain system to make a short winter sojourn among the everglades of southern Florida.

In the tactics of these great birds while performing their immense journeys there is something remarkable even to the casual observer. More than two thousand years ago it was recorded by a student of natural history that, “Olores iter facientes colla imponunt praecedentibus; fessos duces ad terga recipiunt.”

“Swans performing a journey rest their necks upon those preceding; and the leaders receive the weary ones upon their backs.”

And this significant remark has often been confirmed by modern observation.

Owing to the fact that they are more sparsely distributed, that they fly much higher and in smaller numbers than wild geese, the swans are comparatively seldom seen during their migratory flights save in the fastnesses of mountainous districts or at the extreme points of arrival and departure. Hence we see why so little is known concerning the details of their aerial movements.

On the contrary, the semi-annual passage of wild geese is not only a folk-lore phenomenon, but a familiar spectacle to the residents of cities and towns as well as those who spend their days in the rural districts. Now, there is more military precision in the alignment of a large flock of wild geese than the most careful observer ever dreamed of or science investigated.

Here in the fastnesses of our Rocky Mountains there are many exceptionally good opportunities for watching the marvelous evolutions of these birds.

While their flight may be a mile high or more when spanning a level scope of country, as in the prairie districts, they barely clear the more elevated peaks while crossing lofty mountain ranges. Hence it will be seen that an observer on either slope is much nearer the passing birds than an inhabitant of the lower levels or plains.

The well known acute angled form assumed by wild geese in their annual journeys is not a mere fortuitous conceit on the part of the birds, but a true pattern of that diagram formulated by the anserine leaders of long agone prehistoric ages; brave old heroes that piloted their snowy hosts over the storm-lashed wastes of northern latitudes while frost and fire and glacier and drift were so radically changing the topography of our globe.

It can be shown that this particular form of alignment in the flight of geese is just as essential to the convenience and vital interests of the birds as the hexagonal form of honeycomb cells is to the bees that construct and fill them with honey. Nay, it is also true that no other form of alignment in flight could fulfill the conditions required; but we cannot here explain the principles involved in the interesting discussion.

L. Philo Venen.