The subdued tints and notes which almost always mark the female sex, among birds,—unlike insects and human beings, of which the female is often more showy than the male,—seem designed to secure their safety while sitting on the nest, while the brighter colors and louder song of the male enable his domestic circle to detect his whereabouts more easily. It is commonly noticed, in the same way, that ground-birds have more neutral tints than those which build out of reach. With the aid of these advantages, it is astonishing how well these roving creatures keep their secrets, and what sharp eyes are needed to spy out their habitations,—while it always seems as if the empty last-year's nests were very plenty. Some, indeed, are very elaborately concealed, as of the Golden-Crowned Thrush, called, for this reason, the Oven-Bird,—the Meadow-Lark, with its burrowed gallery among the grass,—and the Kingfisher, which mines four feet into the earth. But most of the rarer nests would hardly be discovered, only that the maternal instinct seems sometimes so overloaded by Nature as to defeat itself, and the bird flies and chirps in agony, when she might pass unnoticed by keeping still. The most marked exception which I have noticed is the Red Thrush, which, in this respect, as in others, has the most high-bred manners among all our birds: both male and female sometimes flit in perfect silence through the bushes, and show solicitude only in a sob which is scarcely audible.
Passing along the shore-path by our lake, one day in June, I heard a great sound of scuffling and yelping before me, as if dogs were hunting rabbits or woodchucks. On approaching, I saw no sign of such disturbances, and presently a Partridge came running at me through the trees, with ruff and tail expanded, bill wide open, and hissing like a Goose,—then turned suddenly, and with ruff and tail furled, but with no pretence of lameness, scudded off through the woods in a circle,—then at me again fiercely, approaching within two yards, and spreading all her furbelows, to intimidate, as before,—then, taking in sail, went off again, always at the same rate of speed, yelping like an angry squirrel, squealing like a pig, occasionally clucking like a hen, and, in general, so filling the woods with bustle and disturbance that there seemed no room for anything else. Quite overawed by the display, I stood watching her for some time, then entered the underbrush, where the little invisible brood had been unceasingly piping, in their baby way. So motionless were they, that, for all their noise, I stood with my feet among them, for some minutes, without finding it possible to detect them. When found and taken from the ground, which they so closely resembled, they made no attempt to escape; but, when replaced, they presently ran away fast, as if conscious that the first policy had failed, and that their mother had retreated. Such is the summer-life of these little things; but come again in the fall, when the wild autumnal winds go marching through the woods, and a dozen pairs of strong wings will thrill like thunder through the arches of the trees, as the full-grown brood whirrs away around you.
Not only have we scarcely any species of birds which are thoroughly and unquestionably identical with European species, but there are certain general variations of habit. For instance, in regard to migration. This is, of course, a Universal instinct, since even tropical birds migrate for short distances from the equator, so essential to their existence do these wanderings seem. But in New England, among birds as among men, the roving habit seems unusually strong, and abodes are shifted very rapidly. The whole number of species observed in Massachusetts is about the same as in England,—some three hundred in all. But of this number, in England, about a hundred habitually winter on the island, and half that number even in the Hebrides, some birds actually breeding in Scotland during January and February, incredible as it may seem. Their habits can, therefore, be observed through a long period of the year; while with us the bright army comes and encamps for a month or two and then vanishes. You must attend their dress-parades, while they last; for you will have but few opportunities, and their domestic life must commonly be studied during a few weeks of the season, or not at all.
Wonderful as the instinct of migration seems, it is not, perhaps, so altogether amazing in itself as in some of its attendant details. To a great extent, birds follow the opening foliage northward, and flee from its fading, south; they must keep near the food on which they live, and secure due shelter for their eggs. Our earliest visitors shrink from trusting the bare trees with their nests; the Song-Sparrow seeks the ground; the Blue-Bird finds a box or a hole somewhere; the Red-Wing haunts the marshy thickets, safer in spring than at any other season; and even the sociable Robin prefers a pine-tree to an apple-tree, if resolved to begin housekeeping prematurely. The movements of birds are chiefly timed by the advance of vegetation; and the thing most thoroughly surprising about them is not the general fact of the change of latitude, but their accuracy in hitting the precise locality. That the same Cat-Bird should find its way back, every spring, to almost the same branch of yonder larch-tree,—that is the thing astonishing to me. In England, a lame Redstart was observed in the same garden for sixteen successive years; and the astonishing precision of course which enables some birds of small size to fly from Australia to New Zealand in a day—probably the longest single flight ever taken—is only a part of the same mysterious instinct of direction.
In comparing modes of flight, the most surprising, of course, is that of the Swallow tribe, remarkable not merely for its velocity, but for the amazing boldness and instantaneousness of the angles it makes; so that eminent European mechanicians have speculated in vain upon the methods used in its locomotion, and prizes have been offered, by mechanical exhibitions, to him who could best explain it. With impetuous dash, they sweep through our perilous streets, these wild hunters of the air, "so near, and yet so far"; they bathe flying, and flying they feed their young. In my immediate vicinity, the Chimney-Swallow is not now common, nor the Sand-Swallow; but the Cliff-Swallow, that strange emigrant from the Far West, the Barn-Swallow, and the white-breasted species, are abundant, together with the Purple Martin. I know no prettier sight than a bevy of these bright little creatures, met from a dozen different farm-houses to picnic at a way-side pool, splashing and fluttering, with their long wings expanded like butterflies, keeping poised by a constant hovering motion, just tilting upon their feet, which scarcely touch the moist ground. You will seldom see them actually perch on anything less airy than some telegraphic wire; but, when they do alight, each will make chatter enough for a dozen, as if all the rushing hurry of the wings had passed into the tongue.
Between the swiftness of the Swallow and the stateliness of the birds of prey, the whole range of bird-motion seems included. The long wave of a Hawk's wings seems almost to send a slow vibration through the atmosphere, tolling upon the eye as yon distant bell upon the ear. I never was more impressed with the superior dignity of these soarings than in observing a bloodless contest in the air, last April. Standing beside a little grove, on a rocky hill-side, I heard Crows cawing near by, and then a sound like great flies buzzing, which I really attributed, for a moment, to some early insect. Turning, I saw two Crows flapping their heavy wings among the trees, and observed that they were teasing a Hawk about as large as themselves, which was also on the wing. Presently all three had risen above the branches, and were circling higher and higher in a slow spiral. The Crows kept constantly swooping at their enemy, with the same angry buzz, one of the two taking decidedly the lead. They seldom struck at him with their beaks, but kept lumbering against him, and flapping him with their wings, as if in a fruitless effort to capsize him; while the Hawk kept carelessly eluding the assaults, now inclining on one side, now on the other, with a stately grace, never retaliating, but seeming rather to enjoy the novel amusement, as if it were a skirmish in balloons. During all this, indeed, he scarcely seemed once to wave his wings; yet he soared steadily aloft, till the Crows refused to follow, though already higher than I ever saw Crows before, dim against the fleecy sky; then the Hawk flew northward, but soon after he sailed over us once again, with loud, scornful chirr, and they only cawed, and left him undisturbed.
When we hear the tumult of music from these various artists of the air, it seems as if the symphony never could be analyzed into its different instruments. But with time and patience it is not so difficult; nor can we really enjoy the performance, so long as it is only a confused chorus to our ears. It is not merely the highest form of animal language, but, in strictness of etymology, the only form, if it be true, as is claimed, that no other animal employs its tongue, lingua, in producing sound. In the Middle Ages, the song of birds was called their Latin, as was any other foreign dialect. It was the old German superstition, that any one who should eat the heart of a bird would thenceforth comprehend its language; and one modern philologist of the same nation (Masius declares) has so far studied the sounds produced by domestic fowls as to announce a Goose-Lexicon. Dupont de Nemours asserted that he understood eleven words of the Pigeon language, the same number of that of Fowls, fourteen of the Cat tongue, twenty-two of that of Cattle, thirty of that of Dogs, and the Raven language he understood completely. But the ordinary observer seldom attains farther than to comprehend some of the cries of anxiety and fear around him, often so unlike the accustomed carol of the bird,—as the mew of the Cat-Bird, the lamb-like bleating of the Veery and his impatient yeoick, the chaip of the Meadow-Lark, the towyee of the Chewink, the petulant psit and tsee of the Red-Winged Blackbird, and the hoarse cooing of the Bobolink. And with some of our most familiar birds the variety of notes is so great as really to promise difficulties in the American department of the bird-lexicon. I have watched two Song-Sparrows, perched near each other, in whom the spy-glass could show not the slightest difference of marking, even in the characteristic stains upon the breast, who yet chanted to each other, for fifteen minutes, over and over, two elaborate songs which had nothing in common. I have observed a similar thing in two Wood-Sparrows, with their sweet, distinct, accelerating lay; nor can I find it stated that the difference is sexual. Who can claim to have heard the whole song of the Robin? Taking shelter from a shower beneath an oak-tree, the other day, I caught a few of the notes which one of those cheery creatures, who love to sing in wet weather, tossed down to me through the drops.
(Before noticing me,) chirrup, cheerup
(pausing in alarm, at my approach,) che, che, che;
(broken presently by a thoughtful strain,) caw, caw,