Page:The Zoologist, 3rd series, vol 1 (1877).djvu/235

Rh permit me to cite, prove most undoubtedly that birds do return year by year to the same spot.

On the east coast of Lincolnshire the arrivals of various species, during the autumn months of September and October, are so regular that they may be readily tabulated and predicted to a few days. The same phenomena may be observed, and with even greater certainty, at Heligoland during the periods of the vernal and autumnal migrations. No matter how the weather is at each particular periods of arrival, calm or strong, thick or clear, the birds come, and come, too, with marvellous regularity. They are scarce or plentiful as the case may be, for the abundance or scarcity of migrants at any special locality is due more or less to the state of the weather during the period of passage. The most favourable circumstances for birds passing the sea are calm still periods, or a light breeze, dead ahead, or a few points free. A head wind that is not too strong is the very thing birds like best, but failing that, a "beam wind," to use a nautical expression, seems to be the best. A wind on their quarter, or one aft—that is, having to fly before the wind, particularly if strong—is objectionable; it ruffles up their feathers and otherwise impedes their flight, soonest tiring them out. The consequences of unfavourable winds are that the birds alight on the first coast they reach for rest: under favourable circumstances they would have passed forward far overhead and unseen. Just as a man, fatigued by an arduous or difficult journey, pauses to rest on the way, so the birds alight for rest and quiet; within twenty-four hours, however, they are off again, each to its especial goal in forest, field, marsh, or sea-coast—a goal which it was their steady, predetermined, purpose to reach when they first took wing from the lone tundra, or ice-girdled shore, in the faraway north. They trusted to no aerial currents to guide or drift them passively towards the sunny south, as seeds in the wash of the equatorial currents to the Hebridean shore, but to their own instinct and intelligence—an instinct which thus far has never failed. According, however, to Mr. Rowley, birds have neither impulse nor instinct: they are purposeless creatures with no will of their own, and the sport of every puff of wind. To carry out, then, this theory we must undoubtedly assign to the winds a far greater constancy than they are usually supposed to have, or than anemometers will justify us in supposing them to possess. The hypothesis is as wild as the wind itself. Nothing, indeed, is