But, even after the completion of his education, when he is independent of his parents, and quick and sure as they at capturing fishes down in their own dim element, is it not still a puzzle and a mystery that such a thing can be done? And here I speak not only of the little grebe, but of all birds that dive after fishes, and pursue and capture them in fresh or salt water. We see how a kingfisher takes his prey, or a tern, or gannet, or osprey, by dropping upon it when it swims near the surface; he takes his fish by surprise, as a sparrow-hawk takes the bird he preys upon. But no specialisation can make an air-breathing, feathered bird an equal of the fish under water. One can see at a glance in any clear stream that any fish can out-distance any bird, darting off with the least effort so swiftly as almost to elude the sight, while the fastest bird under water moves but little faster than a water-rat.
Fascination
The explanation, I believe, is that the paralysing effect on many small, persecuted creatures in the presence of, or when pursued by, their natural enemies and devourers, is as common under as above the water. I have distinctly seen this when watching fish-eating birds being fed at the Zoological Gardens in glass tanks. The appearance of the bird when he dives strikes an instant terror into them; and it may then be seen that those which endeavour to escape are no longer in possession of their full powers, and their efforts to fly from the enemy are like those of the mouse and vole when a weasel is on their track, or of a frog when pursued by a snake; while others remain suspended in the water, quite motionless, until seized and swallowed.
CHAPTER XIII
Morning in the valley—Abundance of swifts—Unlikeness to other birds—Mayfly and swallows—Mayfly and swift—Bad weather and hail—Swallows in the rain—Sand-martins—An orphaned blackbird—Tamed by feeding—Survival of gregarious instinct in young blackbirds—Blackbird's good-night—Cirl buntings—Breeding habits and language—Habits of the young—Reed-bunting—Beautiful weather—The oak in August.
Swifts
During the month of July the swift was the most abundant and most constantly before us of all our Itchen-valley birds. In the morning he was not there. We had the pigeons then, all three species—ring-dove, stock-dove and turtle-dove—being abundant in the woods on the opposite side of the valley, and from four o'clock to six was the time of their morning concert, when the still air was filled with the human-like musical sound of their multitudinous voices mingled in one voice. An hour or two later, as the air grew warmer, the swifts would begin to arrive to fly up and down the stream incessantly until dark, feasting on the gnats and ephemeræ that swarmed over the water during those hot days of late summer. Doubtless these birds come every day from all the towns, villages, and farm-houses scattered over a very broad strip of country on either side of the Itchen. Never had I seen swifts so numerous; looking down on the valley from any point one had hundreds of birds in sight at once, all swiftly flying up and down stream; but when the sight was kept fixed on any one bird, it could be seen that he went but a short distance—fifty to a hundred yards—then turned back. Thus each bird had a very limited range, and probably each returned to his accustomed place or beat every day.
These swifts are very much in the angler's way. Frequently they get entangled in the line and are brought down, but are seldom injured. During one day's fishing my friend here had three swifts to disengage from his line. On releasing one of these birds he watched its movements, and saw it fly up stream a distance of about forty yards, then double back, mechanically going on with its fly-hunting up and down stream just as if nothing had happened.