Now is the squirrel’s harvest. Beech-mast and acorns are now in season. I was sitting this morning close to the smooth grey-mottled trunk of an immemorial beech at Waggoner’s Wells when – pat-a-pat, pat – a noise hard by, as of hurrying and scurrying feet, attracted my attention. So loud it was, one might have almost said a troop of skirmishers from Aldershot at double-quick through the woodland, save that it came from overhead; and overhead skirmishing, from “the nations’ airy navies, grappling in the central blue,” is happily as yet a thing of the poet’s prophetic imagination. I looked up into the tree, and there, to my surprise and delight, lo! half a dozen merry squirrels, all foraging together after the rich beech-mast, which forms the larger part of their winters provender. Even as I watched, one of the pretty harvesters descended the trunk nimbly with his sharp small claws, and approached unawares within a few feet of the spot where I was sitting. No sooner did he see me, however, than he gave me one sharp glance from his keen black eyes, perpended for a second whether to trust me or not, and then, this way and that dividing the swift mind, came quickly at the end to the safe conclusion that men were bad lots, even when they pretend to be playing the observant philosopher. So up the smooth bark he darted, quick as thought, finding his foothold by magic, as is the wont of his race, all ignorant of Newton’s troublesome theory of gravitation. Then, when he knew himself well out of reach and secure from pursuit, he turned and laughed back at me with those beady black eyes of his, in merry mood, as who should say, “Ah, great clumsy creature, you can’t follow me here! Don’t you wish you had a gun? Wouldn’t you like to catch me?”

This quaint quality of roguishness, so sadly rare in northern animals, the squirrel possesses, with not a few other monkey-like peculiarities. Such mental traits seem, indeed, to spring direct from the wild life of the woodland. The freedom which the squirrel enjoys in his native trees – the power he possesses of evading pursuit by darting along the small twigs at the end of a bough – gives him a sense of triumph over dog or man which often results in a positive habit of nothing less than conscious mockery. The opossum and the monkeys, equally tree-haunting beasts, have acquired from similar causes the same delight in insulting and ridiculing their baffled enemies. Very monkey-like, too, is the squirrel’s pretty way of holding an acorn between his two fore-paws to feed himself; while in general intelligence and sense of humour he hardly at all falls short of his southern competitor. The woods are everywhere great developers of intelligence: all the cleverest beasts and birds, including parrots and toucans, are almost without exception confirmed tree-dwellers.

I notice, too, that the squirrels are just now doubly preparing for winter; not only are they prudently stocking their larders, but they are also putting on their light suits for the season. For squirrels, even in England, still retain to some extent the ancestral habit, acquired, no doubt, during the great Ice Age, of changing their coats for a lighter one during the snowy months. In Lapland and Siberia, indeed, the local squirrels imitate the ptarmigan and the ermine by turning grey in winter; in Britain, they have lost that habit as a regular climatic change, but the fur, nevertheless, gets interspersed in places with a number of whitish hairs as the cold season approaches. It is a trick of atavism. Your squirrel sleeps away the worst months in his cosy nest, with his bushy tail wrapped like a blanket or a martial cloak around him. Thus, that pretty adjunct serves a double purpose: in summer squirrels employ it as a balance, like the rope-dancer’s pole; in winter they use it as a convenient coverlet. Now and then, in February, if a warm day turns up, they wake from their doze for a short spell, and visit one of the granaries where their nuts are stored. But, like prudent beasts that they are, they never lay by their treasure in their own nests, because their too frequent going and coming while hoarding nuts might attract attention, and so betray them unawares to the too observant stoat or the inquisitive weasel. They even take the precaution to spread their investments widely, so to speak, by garnering nuts and acorns in several holes at once among the trees that surround their own family residence.

When spring returns the squirrel emerges, a sadder and decidedly a thinner beast. But there are now no nuts, no seeds, no grains; so he takes, against his will, to the young bark and tender shoots of the trees around him. About the same time, too, the squirrel’s fancy lightly turns to thoughts of love; the young of last year’s brood begin to mate themselves. And a pretty sight the mating is, indeed. I was strolling one day through the Nower at Dorking – a lightly wooded park – when I saw by chance one of the daintiest little idylls of real life I have ever yet been lucky enough to witness. A tiny female squirrel emerged all at once from a hole in an oak-tree, hotly pursued close behind by two ardent suitors. Round and round the trunk they ran, now up, now down, all regardless of my presence; the little lady once and again pretending to let one or other of her wooers overtake her, then pausing and looking back at him with her roguish black eyes, and finally darting away with true feminine coquetry just as he thought he had caught her. Ha, ha! the wooing o’t! I stood and watched the pretty little comedy for full twenty minutes; and all the time it was as clear as crystal for which of her two admirers that arrant little flirt had the greater inclination. Not that she ever let him see it himself too plainly; she sometimes encouraged him awhile, and sometimes his rival. She was coy, she was forward, she was bewitching, she was cold; she employed every art known to female wiles – in one word, she was a woman. I wished those who doubt the reality of selective preferences in the lower animals could have been there to see. It was a sweet little courtship. At last the tiny coquette made her choice quite plain; and then the discomfited suitor went on his way, crestfallen, while his successful rival, too overtly triumphant, and rejoicing in his luck, gazed after him and jeered at him.

I am happy to add, however, that squirrels, once mated, are models of propriety in their domestic relations. They are strictly monogamous; they pair for life; and they constantly inhabit the same dwelling. That last is surely a pitch of respectability to which not even the blameless London clerk who “always comes home to tea” has as yet attained. He has been known to flit on quarter-days.

XXIX.
A DRAINED FISHPOND

I called in at my neighbour Major Warren Pauncefote’s this afternoon, and found he was just engaged in draining the fishpond by his garden. He is going to deepen it and to puddle the bottom, so as to make it fit for his boys to swim in. Meanwhile he has transferred all the larger carp to a stone trough in the back yard, where I saw at once there was not half enough water for them. I’m sure he didn’t mean to be cruel, for he is the humanest soldier that ever spitted Fuzzy-wuzzy in the Soudan on his sword; but all the same, to any one who understands the prime needs of fish-life, the condition of those poor carp was most sad to look at. As every one knows, they breathe the oxygen dissolved in water; and as hundreds of them were confined in this Black Hole of Calcutta, the amount at their disposal was, of course, quite inadequate. Some of the poor things were dead or dying, turning on their lustreless sides in the pathetically helpless way of suffocating fish; the others kept coming up every now and then to the surface, gasping for breath, and gulping down great open-jawed mouthfuls of air, to relieve their misery. No doubt the oxygen they thus swallow enters the body-cavity, and slightly assists them in aërating the blood, though much of it, also, may pass in the ordinary way through the gills, which are the regular and normal respiratory organs. It is always interesting to me, however, to watch fish when they come up thus to drink air at the surface, as goldfish often do when thoughtlessly confined in too small a glass basin; for in this instinctive act, as modern biologists now generally allow, we have the first faint beginnings of the evolution of lungs and the habit of air-breathing. Nay, more, terrestrial life itself, as a whole, depends in the last resort upon just such first feeble gaspings and gulpings. For lungs are nothing more, anatomically speaking, than developed swim-bladders, connected by a definite passage with the external air, and provided with a more or less perfect muscular mechanism for inhaling and expelling it.

In most fish, and in all the rudest types, the swim-bladder is merely a float or balloon, which can be filled with air, and compressed or expanded, so as to make the animal rise or sink at pleasure. But many fish exist in tropical ponds and shallow swamps to whom what has happened artificially to the carp in my friend’s ornamental water happens naturally every dry season; the marshy sheets in which they live evaporate altogether, and they are therefore compelled to lie dormant in the mud without food or drink for many weeks at a time. Under these peculiar circumstances, their air-bladder has gradually developed into a true lung; and, what is odder still, we possess in various countries distinct specimens at all the intermediate stages from air-bladder to lung in proportion as the ponds which they haunt become dry for longer or shorter periods. The bow-fin of the United States, for example, lives in turbid waters which do not quite dry up, but it has acquired the habit of rising to the surface every now and then, and gulping in large mouthfuls of air, which enter its swim-bladder. It does so most frequently when the water is foul, and there has been little rainfall – in other words, when there is a scarcity of oxygen. Accordingly, its air-bladder – though not yet a true lung – is spongy and cellular in structure, being adapted for aërating the blood that passes through it. The mud-fish of Queensland, again, to take a further stage, is a six-foot-long fish which inhabits loaded streams, where its gills do not suffice it for proper respiration; it has therefore altered its swim-bladder into a rudimentary lung, more advanced than the bow-fin’s, and full of air-cells, richly supplied with blood-vessels, but consisting still of a single cavity. Nevertheless, even this imperfect lung enables the mud-fish to stroll away from its native streams at night, and wander at large on dry land by means of fins which are almost legs, and which act like the sprawling limbs of certain southern lizards. In that unnatural environment it browses on green leaves, and otherwise behaves in a most unfishlike manner. Finally, to complete our rough survey, the African lepidosiren makes its home in waters which dry up completely during the hot season; and it therefore hibernates (or rather, æstivates) for months together in a cocoon of hard mud, where it breathes at its ease by means of true lungs, completely divided into lateral halves, and approaching in structure those of an air-breathing reptile.

This interesting series of living evolutionary fossils – links that are not missing – is completed for us in some ways by the frogs and toads, which recapitulate, as it were, in their own lifetime just such an ancestral developmental history. Each of them begins life as essentially a fish – that is to say, as a tadpole breathing oxygen dissolved in water, by means of gills, and possessed of no limbs for terrestrial locomotion; he ends it as essentially a full-grown land-reptile, breathing atmospheric air by means of lungs, having discarded his now needless fin-fringed tail, and possessed of jumping legs of great muscular power. And the metamorphosis he thus undergoes answers exactly to just such a drying-up of the ponds that bore him. In early spring, when the temporary puddles are full of water, the parent frogs lay their spawn by hundreds in the ancestral element; and soon the little black tadpoles – true fish of a primitive type in all but name – swarm forth and swim in seething masses in the momentary medium. But as the sun begins to dry up the water in their dwelling-place they lose their fins and gills, pass from fish to amphibians, and shortly hop ashore, provided with four legs and a pair of lungs specially adapted for direct air-breathing. There we have a marvellous piece of evolutionary magic still going on every day before our eyes, which would sound incredible to us if a man of science reported it for the first time from Central Africa or New Guinea. The frog, in short, shows us successively in his own person the self-same stages of development which the various mud-fish preserve for us in distant regions, as types of distinct and unrelated species.

XXX.
AN INTERVIEW WITH A COCK-SPARROW

“Believe me,” said the sparrow, “it pays to be civilized.”

“You seem to have found it so,” I answered. “You and the rook, I take it, are just the two of our birds which have lost nothing and gained much by man’s presence in our island.”

“I believe you,” said the sparrow, cocking his head on one side. He seemed ill to recognize the solemnity of being interviewed, which to the human subject is like having your photograph taken, combined with a compound visit to the dentist. “We are a dominant race, you see; that’s just where it is. We have adapted ourselves to the environment. Birds like jays and hawfinches, now, are too shy and retiring: as civilization advances, they retreat and skulk and can’t march with the age; but we and the rooks, we take advantage of every increase of human population to redouble our numbers. As fast as cultivation grows, we grow; man exists to provide us with food and shelter.”

“Then you think your race has increased, and is still increasing?” I asked.

“Not a doubt of it, my dear sir. We have multiplied enormously. Before the age of tillage, we were probably a small and unimportant group, no more conspicuous or remarkable in any way than the wretched little siskins, or the grasshopper-warblers. But as cultivation develops, we develop, if you will excuse my Latin, pari passu. (Oh, yes, I know Latin well, because a near cousin of mine is the Passer Italiæ.) However, as I was going to say when you interrupted me with a question, we have spread about everywhere that grain will grow in Europe. That’s because we are bold, courageous birds, not afraid of every passing object we see, like the bluethroats and the creepers; while at the same time we are cautious, quick, eager, and wary, and get out of the way of danger at a moment’s notice. My own opinion is that even in Europe we must have been a mere handful of birds before cultivation spread, and that since that time we have pushed ourselves by our energy and enterprise into a leading position. About great cities alone, we may be reckoned by our myriads; and then, just look at our colonial expansion!”

“You have emigrated largely, I believe,” I said, “to America and the Colonies?”

“Bless my soul, yes; we have followed European civilization almost everywhere. We allow mankind to go ahead of us for a few years, just to prepare the way, and get our corn and oats into working order; and then we gain a foothold in the newly acquired lands, and naturally oust the uncivilized natives. We have annexed America, and are killing out inferior types in many other regions. What do I mean by inferior types? Why, non-sparrows, of course; such lower grades, don’t you know, as Australians and New Zealanders.”

“Excuse my asking a delicate question, but do you do much damage, from the farmer’s point of view, to the crops and the gardens? You see, we men have a narrow-minded way of regarding these things from a somewhat restricted human standpoint.”

The sparrow gazed at me hard out of the corner of his eye. “Well, I don’t want it put in print,” he said confidentially, “for farmers are so unreasonable; but I will admit that at certain times of the year we do pick up a good many seeds out of fields and gardens. But then, consider how many insects we help to eat up. Why, I lived for a week last year upon aphides – what the farmers call bean-bugs. We must be philosophical, my dear sir; we must be philosophical. There’s a give-and-take in these affairs, you may depend upon it.”

He ruffled his neck as he spoke, and I observed it was marked by a conspicuous black band I had never before noticed.

“That’s a pretty cravat of yours,” I interposed, just to change the subject.

“Yes, it is pretty,” he admitted, swelling himself out a bit as he said it. “Our women don’t have them, you know, nor the young ones either. This beautiful decoration is the peculiar glory and special distinction of the adult cock-sparrow.” And anything cockier than he looked at that moment it would be hard to imagine.

It occurred to me as he spoke that I had seldom seen a slenderer form of masculine adornment on which to pride one’s self, till I suddenly recollected that a black moustache on a human face must be as relatively inconspicuous to any other species; and I have never noticed that the possessors of well-grown black moustaches under-rated their importance.

“You have a large family, I believe,” I remarked, as he chirped to his mate cheerily.

“Oh, several of them,” he answered with a nonchalant air; “sometimes as many as three yearly. We are a dominant race, you know, and we don’t always trouble to build our own nests; we just drive out a house-martin, or take possession of a sand-martin’s burrow in a cutting. Arbitrary, did you say? Oh, well, you see, we are sparrows; and, of course, we can make a much better use of them. Poor devils of martins, they have to go elsewhere, and house themselves as best they may – the survivors, that is to say, for a good many of them get killed and torn to pieces in the process of readjustment. They’re such savages, you see; we’re obligea to be sharp with them. Why, I’ve known a horde of house-martins fight in defence of their wretched mud hovels till we were compelled to exterminate them. Well, I’m off now; ta-ta! Mind you send me a copy of your paper with this interview. And oh, by the way, if you describe my wife, just make the most you can of that pale streak over her eye, will you? It is all she has to be proud of, poor thing. She’s not as distinguished-looking as I am, of course; but let her down gently, please; do let her down gently.”

XXXI.
THE GREEN WOODPECKER

We live so closely and familiarly with nature on the isolated hilltop, where my cottage is perched, that we often behold from our own drawing-room windows pretty rural sights, which seem intensely strange to more town-bred visitors. A little while since, for example, I was amused at reading in an evening newspaper a lament by a really well-informed and observant naturalist on the difficulty of actually seeing the night-jar, or fern-owl, alight upon a tree, and stand, as is his wont, lengthwise, not transversely to the branch that bears him. Now, from our little bay lattice that doubting Thomas might see the weird bird nightly, not twenty yards off, the whole summer through, crooning its passionate song, full in view of our house, from a gnarled old fir-tree. So again this morning, at breakfast, we raised our eyes from the buttered eggs and coffee, and they fell at once on a big green woodpecker, creeping upward, after his fashion, along a russet-brown pine-trunk, not fifteen feet from the place at table where we were quietly sitting. One could make out with the naked eye the dark olive-green of his back, relieved by the brilliant crimson patch on his gleaming crown. For several minutes he stood there, clambering slowly up the tree, though we rose from our seats and approached quite close to the open window to examine him. When he turned his head, and listened intently after his tapping, with that characteristic air of philosophic inquiry which marks his species, the paler green of his under parts flashed for a second upon us; and when at last, having satisfied himself there was nothing astir under the bark of the stunted pine, he flew away to the next clump, we caught the glint of his wings and the red cap on his head in motion through the air with extraordinary distinctness.

The yaffle, as we call our red-headed friend in these parts, is one of the largest and handsomest of our woodland wild birds. About a foot in length, by the actual measurement, “from the end of his beak to the tip of his tail,” he hardly impresses one at first sight with a sense of his full size, because of his extreme concinnity and neatness of plumage. A practical bird, he is built rather for use than for vain gaudy display; for, though his colour is fine, and evidently produced by many ages of æsthetic selection, he yet sedulously avoids all crests and top-knots, all bunches and bundles of decorative feathers protruding from his body, which would interfere with his solid and business-like pursuit of wood-burrowing insects. How well-built and how cunningly evolved he is, after all, for his special purpose! His feet are so divided into opposite pairs of toes – one couple pointing forward and the other backward – that he can easily climb even the smooth-barked beech-tree, by digging his sharp claws into any chance inequality in its level surface. He alights head upward, and moves on a perpendicular plane as surely and mysteriously as a lizard. Nothing seems to puzzle him; the straightest trunk becomes as a drawing-room floor to his clinging talons. But in his climbing he is also aided not a little by his stiff and starched tail, whose feathers are so curiously rigid, like a porcupine’s quills, that they enable him to hold on and support himself behind with automatic security. Long ancestral habit has made it in him “a property of easiness.” A practised acrobat from the egg, he thinks nothing of such antics; and when he wishes to descend he just lets himself drop a little, like a sailor on a rope, sliding down head uppermost, and stopping himself when he wishes by means of his claws and tail, as the sailor stops himself by tightening his bent fingers and clinging legs round the cable he is descending.

But, best of all, I love to watch him tapping after insects. How wise he looks then! how intent! how philosophic! When he suspects a grub, he hammers awhile at the bark; after which he holds his head most quaintly on one side with a quiet gravity that always reminds me of John Stuart Mill listening, all alert, to an opponent’s argument, and ready to pounce upon him. If a grub stirs responsive to the tap, tap, tap of his inquiring bill – if his delicate ear detects a cavity, as a doctor detects a weak spot in a lung with his prying stethoscope – in a second our bird has drilled a hole with that powerful augur, his wedge-shaped beak, has darted out his long and extensile tongue, and has extracted the insect by means of its barbed and bristled tip. The whole of this mechanism, indeed, is one of the most beautiful examples I know of structures begotten by long functional use, and perfected by the action of natural selection. It is not only that the bill is a most admirable and efficient boring instrument; it is not only that the tongue is capable of rapid and lightning-like protrusion; but further still, the barbs at its ends are all directed backward, like the points of a harpoon, while the very same muscles which produce the instantaneous forward movement of the tongue press at the same time automatically on two large salivary glands, which pour forth in response a thick and sticky secretion, not unlike bird-lime. The insect, once spotted, has thus no chance of escape; he is caught and devoured before he can say “Jack Robinson” in his own dialect.

But though the green woodpecker is so exceedingly practical and sensible a bird, built all for use and very little for show, he is not wholly devoid of those external adornments which are the result of generations of æsthetic preference. Dominant types always show these peculiarities. His ground-tone of green, indeed, serves, no doubt, a mainly protective function, by enabling him to escape notice among the leaves of the woodland; and even on a tree-trunk he readily assimilates with the tone of the background; but his brilliant crimson cap is a genuine piece of decorative adornment, which owes its origin, no doubt, to the selective preferences of his female ancestors for endless generations.