The Dipper. (Cincius aquaticus)

The Fulmar Petrel lays but one egg: yet it is believed to be the most numerous bird in the world. (Darwin.)

As more individuals are produced than can possibly survive, there must in every case be a struggle for existence, either one individual with another of the same species, or with the individuals of a distinct species, or with the physical conditions of life. (Darwin.)

I feel sure that if ever human ingenuity can devise a clockwork or electric bird to bob up and down, to fly - either in the air or under water - and to sing; the result will approximate the form and movements of the common dipper or water ousel more than any other bird that is known in England.

Everything about the bird is mechanical. Its son g could be nearly produced by a wet cork on a window pane, and its two screamy notes - uttered on the wing -are far more artificial than those of the kingfisher or sandpiper, who fly past one in much the same hurried manner; generally 11 pairs, and at much the same height above the water. The note of the sandpiper seems to come from a clarinet; while the squeal of the kingfisher, or the squeak of the dipper, recall experiences of moving heavy; furniture or opening rusty shears.

When first one begins to learn trout fishing the dipper may make our acquaintance. Unnoticed as he perhaps is during the first ten minutes of our casting across the fast water on an open March day, he soon catches the eye; and the tyro with the rod becomes aware of a dark slaty grey or a light sooty black bird with a white breast sitting on a wet stone just the other side of the run some few inches above the water, who seems wound up to make a certain fixed number of bobs at intervals.

He is like a schoolboy somewhat water shy, who has undressed and is standing at the edge of the swimming bath constantly gesticulating with his hands and knees as though about to take a splendid header, and who still remains in position. The dipper always appears about to fly off or about to take a header, and yet stops on his stone as though intending to wait and see a fish caught before he takes action.

He is to the angler what the robin is to the gardener, and in the friendly position he takes up says, like Laura, ' so long as you are pleased to stare I'm pleased to stay.' And if you cast too close to him he at length winds his internal machinery up for flight and whirrs off like an aeroplane down stream or upstream - never in any other direction, cutting never even off a corner if the river makes a sharp bend, and alights upon a similar stone two hundred yards away to recommence his twitchy watchfulness up that stretch of water which he and his mate have leased from nature for the season.

Every trout fisherman must notice how each quarter of a mile of water contains its pair of ousels. They are as jealous of their beat as policemen and hold themselves aloof from all relations, living their two hundred yards up or down stream from their favourite central stone just opposite the rocky cascade which they have settled upon as their nesting place. It would be interesting to know and to trace precisely what becomes of the new brood when once the parents are persuaded that the time has arrived for their progeny to be sent out into the world. The beats above may be taken by their uncles or by their cousins once removed, and also the beat below. Do they seek another stream or do they actually combat with their own parents for the possession of that length of water where they first tasted the sweets of caddis worms shrimps or snails? I certainly have seen dippers fight. A species of flying warfare mixed with stridulous screams, and possibly these are sharp actions at law after which the title deeds change hands and the water rights with them.

A puzzle which field naturalists have never explained is why should not the dipper be a far commoner species than it is. Two and sometimes three broods a year are hatched, generally successfully, and the average number of eggs laid is four or five. The bird has hardly any enemies. Even the average schoolboy who spends his Easter holidays close to a stream seldom finds a nest, or if he does locate one sees with regret that it is the other side of the stream under a tangled overhanging bank. Yet the dipper like the nuthatch is often unknown to those who take suburban walks, and is even spoken of as an unfamiliar bird.

The starling rears as a rule but one brood. It is shot at by every cockney sportsman who can borrow a gun. Its nest is rifled by mere urchins and its young becomes a prey to any cat or catapult in the district. Yet countless flocks are seen, and the bird is reckoned as common as the hedge sparrow. We have all found dead thrushes or starlings on many a winter's walk. I have never seen a dead dipper on the sandy beach of any stream nor have I ever seen the bird attacked. The nuthatch also enjoys an immunity from birdsnesting boys and must rear its young with comparative success year after year, yet how few are seen excepting by those who really set out to look for them. The balance of nature so admirably kept in hand is hard to analyse.

In the case of the dipper there is a statement in Morris' British Birds to the effect that " one pair - or at least a pair - built in the same place for thirty one years, rearing three broods each year." Can they have reared three hundred young during that period? If so then their descendants would be sufficient to monopolise a river valley of ten or fifteen miles. No one probably has seen fifty dippers in the whole length of Dovedale. I have not seen twenty.

Many of the best days fishing have been secured by an angler who takes an interest in watching the habits of a dipper. Tired of walking along on a ruffled day in April, casting up stream every yard of the way upon the Scotch principle that the fly which catches the most fish is the one oftenest upon the water, he at length spears his rod with an impatient jerk into the wet grass, makes a cushion of his mackintosh and plumps himself down on it determined to knock off for a space and smoke a consoling pipe. lie sees a small bird fly off a stone and deliberately attempt suicide by drowning.

He wonders if like Alice and the rabbit he has been dreaming; but his interest is aroused and he finds himself too absorbed to fill his pipe. He watches the dipper flutter right into the sparkling stickle and behave like the penguins n the Zoological Gardens, swimming, diving, and almost running under water in search of food. If he keeps unobserved he can in the space of half-an-hour become a witness of most of its life's history, and will in addition be rewarded by noticing a brace of good fish rising almost within casting distance. Without getting up, he reaches for the rod, places a red upright a foot above the rise, and to his unexpected delight finds it well taken and the fish hooked before he has risen to his knees. He plays him carefully, backing down stream with shortening line and rod well up, and after guiding him past an ugly strand of blackberry slips the net underneath and lifts out a curvetting ten ouncer as bright as yellow amber.

Thus we are all wooed from the cast-on-chance principle towards the methods of dry fly, or at least of only fishing for the rise. The pleasant interlude of watching the dipper has taught the angler that the successful basket filler is he who is most often sitting on the bank, not too close to the edge, with grounded rod, gazing at, instead of constantly thrashing, the stream.

The nest of the dipper is difficult to see but easy to trace by watching the movements of the birds. Towards the end of April they lose much of their shyness and gradually betray the close whereabouts of their bulky home. The nest itself is usually some five feet above the ground or water, in the opposite bank among the bared roots of a tree. It looks at first like a lump of debris left stranded by flood water. Generally it is found just out of reach and requires a boat or a bridge to get at it. I have located scores which followed this description; but often again it can be found under an old bridge and even among the fir trunks that are laid to form a weir.

Among wet rocks near a dam or a waterfall is another favourite locality. The nest is something between a wren's and a housesparrow's: occasionally very large and straggly, covered with a dome always and with the entrance hole at the side, lined carefully with oak or beech leaves, dried grass and hits of river weed in preference to hair or feathers. Indeed the two latter I have never noticed. The eggs are plain white, four or five in number; usually found the second week of April in Devonshire, or a week later in Yorkshire.

So frequently do they pass and repass that I have touched them with the line in casting; and have known of one being hooked foul in the wing by an angler, and brought to bank after diving furiously.