HOW A BIRD IS BUILT
Since its feathers are the one thing that marks a bird, outwardly, as different from other classes of animals, we ought first of all to learn what feathers are, and what purpose they serve. A quill feather, such as may be picked up in any farmyard, has a horny, hollow stem or "shaft," which is bare at the closed large end or "base," but has two soft, winglike expansions toward its tapering end that together make its "vane." This thin, flat vane consists of delicate branches, "barbs," studded with tiny hooks, the "barbules," holding each adjacent branchlet in place, but letting the whole vane bend and spring. The whole beautiful thing is really very strong and elastic, as it must be to push as hard against the air as a bird's wing has to do. The vanes vary much in shape, and in the degree to which the branchlets are disconnected into a fluffy looseness. Ostrich plumes, and those of the birds of paradise, owe their beauty to the fact that each branch in the vane is loose, and bears little disconnected branches of its own; and in many feathers no vane at all grows, so that they resemble hairs, when fine, and bristles when coarse, as is seen about the mouth of the whippoorwill and some flycatchers. The nestling plumage or "down" is of this character. The lovely plumes of egrets are slender stems of feathers having in place of a vane scattered soft hairs. In some sea birds the feathers are so stiff and hard as to be almost like scales. Those of water birds, and especially the divers, are wonderfully close, thick, and greasy, so that the down that forms an undercoat for warmth, and the skin beneath it, never gets wet.
Feathers, then, serve their wearers first of all as clothing—very thick and warm in birds of cold places; and doubtless this beneficial modification of the primitive reptilian scale, by reason of its conserving the warmth of the body, and gradually increasing the temperature of the blood, has been largely instrumental in enabling birds to rise so far above the grade of their cold-blooded and sluggish ancestors.
Most animals whose lives are spent in the open air and light show more or less color in their coat, but none are more beautifully adorned than birds. The most brilliant examples are to be found in the tropics, and some of the gayest in our colder land, such as the tanagers and humming birds, are strays from large tropical families noted for gaudy attire.
The color we see in plumage may be due to either of two conditions. It may, as is usually the case, be simply coloring matter deposited in the substance of the feathers. But where the plumage gleams with changing rainbow lights, as on the fiery throat patch of the humming bird, on the neck of a dove or on the purple-black coat of the grackle (crow blackbird), these splendid reflections are caused by very minute wrinkles on the feathers, that break up the light. It is the same effect, called "iridescence," as is seen on the mother-of-pearl and on a soap bubble. Blue is usually an effect produced by certain coloring matter not blue underlying a thin covering of feather substance; and when you pound a blue feather into dust that dust will be black or gray—or, at any rate, not blue. Birds of the same group are colored much alike, as a rule.
In some cases the style of colors worn appears to be the best for the safety of the birds of the group by making them hard to see as long as they keep still. Thus most birds whose lives are passed on or near the ground, and which build their nests there, are dull in coloring; they are in danger from more enemies than are tree-dwelling birds, and must be able to hide better. No bird of nocturnal habits is brightly colored. It is mostly among the small, quick-flying species, such as warblers and finches, that we find the gayly dressed ones. They are birds of the sunshine, and usually migratory. In most cases when birds have a plain dress there is little difference in it between the male and the female; but whenever you find a species of bird wearing a gay, ornamental dress, it is almost always the male that sports these fine feathers, while the female and young are clothed in dull yellow, drab or brownish tints. This appears to be another measure of safety. The males can wander about, look out for themselves, and take to flight when danger threatens; but their mates must sit quietly on their nests, and trust for safety for themselves and (what is really more important) their eggs or young mainly to not being seen. In their plain colors they blend into the foliage and the shadows amid which they sit, and so are more likely to escape the sight of prowling foes.
Feathers are not intended to remain permanently; they become worn and faded, or are lost, so that at regular intervals the bird needs a new suit of clothes. Twice a year, therefore, in spring and autumn, they are pushed out by new ones sprouting in the same feather-growing pits. This shedding of the feathers is called "molting," and it is analogous to the shedding of the outer, horny pellicle of its skin by a snake or lizard. Their molting is not very noticeable in land birds, because the feathers drop out little by little; otherwise the poor creatures would be left quite naked, and unable to fly. In most birds the new feathers that come in are the same in pattern and color as those they displace, so that the new plumage differs little if any from season to season; but some birds acquire a new coat for winter that is decidedly different, and sometimes snowy white, making them inconspicuous amid the snow.
The largest and most important feathers in a bird's outfit are those of the wings and tail, by means of which it flies and controls its progress. How birds are able to keep themselves aloft in the air, and move through it at will, is not yet understood. That it requires great strength of wing muscles, and rigid support for them is evident. Therefore we find the head of the arm bone (humerus) fastened by stout ligaments to a great shoulder blade sunk in the flesh beside the fore part of the spine, and also braced in two directions by other interior bones, one of which extends down to join its opposite fellow at the front end of the breast bone, and form the "wishbone" (the united coracoids). This solid bracing by bones and tying by ligaments gives the needed firmness to the wings; and enables their powerful muscles to work them.
How great these muscles are you will know when I tell you that the thick mass of "white meat" in the breast of the fowl carved at your table consists only of the two principal muscles that move the wings when a downward stroke is made. They, in their turn, are attached at the base to the broad surface of the breastbone, or "sternum" and its projecting keel. Beyond the wrist joint stretches a large, misshapen hand, which consists mostly of one great forefinger, in the tough flesh of which the big quills, or outer flight feathers, called "primaries," are rooted. Lying over their bases, when the wing is folded, is a row of somewhat smaller quill feathers called "secondaries." Above those are the small and close "wing coverts."
The tail is very important in guiding and checking a bird in flight, and is useful in various other ways, and may also be extremely ornamental. The tail quills are always in pairs, making an even number of feathers. This results from the reduction to a mere stub of the long clumsy tail worn by the archæopteryx and its fellows. The quills continued to grow in pairs out of the side of the tail as it diminished until all that there is room for (ten or twelve pairs) are now rooted side by side around the edge of the condensed coccygeal bones.
Birds are, as a class, the most active of animals, and their temperature is highest; this means a large consumption of oxygen, and the windpipe is usually capacious, yet the lungs are not large, but are supplemented by another apparatus for aeration. Opening out of the lungs are several pairs of air sacs, amplest in those birds that are much on the wing, which not only occupy spaces between the muscles and organs within the chest, but in many cases extend into the neck and head, and even into the limb bones, which in most birds are hollow.
| Photo, Keystone View Co. |
| THE PELICAN, NOTABLE FOR ITS THROAT POUCH |
Here is a suitable place to say a few words about how a bird sings. The breath enters and leaves the windpipe through the larynx in the back of the mouth—an organ which, in our throats, contains the vocal cords and voice-producing apparatus; but in birds the larynx is unimportant, for their voice organ is near the lower end of the windpipe, and is called "syrinx" or music box. It consists of an enlargement and modification of the bony rings about the windpipe at the point where it forks into the two branches to the lungs; and incloses vibrating membranes. It is also furnished with small muscles that act to expand or contract the tube and its inner fixtures, thus regulating the column of air forced through the syrinx when the bird calls or sings. These muscles thus control the space and the shape of the opening, and the tension of the membranes that serve as vocal cords. The muscles of the syrinx vary greatly in number and efficiency among birds; and many kinds classed as "singing birds" (Oscines) do not sing melodiously or tunefully because their music box is imperfectly supplied with the proper muscles. They have the instrument, but are unable to play upon it.
| Photo, Keystone View Co. |
| PEACOCK WITH BRILLIANT TAIL SPREAD |
| Photo, A. N. Mirzaoff |
| SACRED PHEASANT |
The 10,000 or more different kinds of birds now living in the world are classified in fifteen orders, of which the lowest in rank is that of the ostriches, and allied ratite birds, mostly extinct, that stand in a place apart by reason of their archaic structure and inability to fly. The ostrich is still wild in the arid districts of Africa, Arabia, and Mesopotamia; the rhea is Patagonian; the emus and cassowaries belong to Australia and New Guinea; the apteryx, or kiwi, still survives in New Zealand; and several gigantic ratite birds have recently become extinct in New Zealand and in Madagascar, where egg shells, laid by the prehistoric æpyornis, that will hold two gallons are still found. Some species of these birds were seven feet in height.
[CHAPTER XXIII]
SOME NOTABLE WATER BIRDS
From these relics of geologic antiquity the remainder of the birds now living, and their fossil ancestors as well, differ fundamentally, and are united in a division whose badge is the keel on the sternum; hence they are termed "carinate" birds (Carinatæ). The list begins with the most archaic order, that of the loons, of which three or four species are named, but they are hardly separable. They are as big as geese, have black backs checkered with white spots, white undersurfaces and heads purplish black, variously marked; and these heads and necks have a very reptilian look, as they stretch forward their heads inquiringly, or utter the "wild laughter" that seems so consonant with the lonely waters they frequent. The reptilian suggestion is even stronger in their cousins the grebes, known to gunners as "die-dappers," "hell-divers," etc., on account of the quickness with which they will disappear when alarmed. The family badge is on the feet, where the toes are not connected by a full web, as in loons, but every toe is margined by a flange of firm skin with a scalloped margin. Grebes have a way of swimming with the whole body under water, when the exposed head and neck look very "snaky." The brown and white plumage of grebes is exceedingly close and dense, and their indifference to wet and cold is shown by the fact that their nests are mere rafts of sodden weeds often so loosely tied to the rushes that they go adrift. Grebes abound on all northern waters and are rarely shot since the taking of their silvery breasts for hat ornaments has been stopped.
The penguins constitute an order limited in range to the antarctic region. Their picture is in everybody's mind—a bird that stands as erect as a soldier on two almost invisible legs and a short stiff tail, and carries a small head, sometimes plumed, with a strong pointed bill. The picture usually represents the great flocks that resort in the brief summer to their rocky breeding places on icy shores, each female guarding and incubating her two eggs in the rudest of nests on the ground. These antarctic "rookeries" sometimes hold tens of thousands. During the rest of the year the penguins are at sea, or under it, behaving more like seals than birds, for their scalelike plumage is impervious to water, and their stubby wings are in effect flippers by which they swim under water, the strong-webbed feet acting only as rudders until they come to the surface and can paddle. Penguins feed on crustaceans and mollusks mostly, but also on fish and sea weed.
Next comes that group of wide sea wanderers, the albatrosses and petrels, united in the family Procellariidæ, whose special mark is found in the two bony tubes along the top of the beak that contain the nostrils. Of the albatrosses many species are known, nearly all inhabitants of the southern oceans, although two or three of the largest regularly visit the North Pacific coast, and more rarely one strays into the North Atlantic; certain small species frequent the western coast of South America. The one best known is the "wandering" albatross, whose wings spread nine or ten feet, yet are only nine inches wide. They spend their whole lives on the open ocean, and undoubtedly sleep there, regardless of storm or calm; but in summer land on some lone antarctic island or lofty shore, and construct a heap of mud and rubbish on top of which they deposit two chalky eggs.
Their relatives, the oceanic petrels, are much smaller as a rule, and some no bigger than sparrows. They are of many kinds, including fulmars, shearwaters, etc., and nearly all are black or sooty brown, usually with touches of white. Most of the group are denizens of the southern hemisphere, but some belong to the north and are migratory; and the eastern Atlantic and Mediterranean are the home of the original stormy petrels, which sailors call "Mother Carey's chickens" and regard with mingled superstition and affection; Leach's white-rumped petrel, of our New England coast, shares this name. Some of the far-southern species are almost as big as albatrosses. Petrels get their food from both the waves and the shore and follow ships on long voyages in hope of scraps of flesh thrown overboard. Most of them breed in holes dug in the topsoil of sea-fronting cliffs, and lay white eggs; many hide in these holes by day, and go out only at night, filling the air with wild cries while they hunt; but fulmars and shearwaters, which make rude nests on rough shores or on cliff ledges, often in vast colonies, go abroad in daylight, and throng on the Grand Banks and wherever else fishing is going on.
Next, in the classification based on structure rather than on superficial resemblances, comes a large assemblage of water birds, some exclusively marine, others of inland waters. Here are placed those long-winged, graceful, oceanic flyers, the tropic birds, and the many kinds of gannets, snowy white, that soar and plunge like falcons as they sweep over the waves and pick up incautious squids, fishes, etc. Most of them are tropical, but one gannet is well known on both shores of the North Atlantic where it nests in thousands on the cliff faces that bound such lofty islets as the Bass Rock near Edinburgh, the Hebrides, and Bird Rock in the Gulf of St. Lawrence. The flight is easy and powerful, and the food is caught by a hawklike plunge.
The nearest relatives of these white birds are the cormorants, which are shining black, glossy, with blue or green reflections. They are scattered over the whole globe, most of them along seashores, but many breed on inland lakes and swamps, usually in large companies. Unlike the sweeping and beautiful flight of the far-wandering gannets, these birds appear heavy on the wing; and instead of snatching their food from the surface they dive after the fishes on which they feed, and pursue their slippery prey under water, swimming with both wings and feet, and dodging here and there in a most surprising way. Their bills are peculiarly well adapted to holding what they catch; and a near relative of the West Indies and southward often spears its prey with its bill. This is the darter or snakebird, so called because its long neck and small head give it a peculiarly snakelike appearance as it swims with nothing above the surface but the slender head, and that making scarcely a ripple.
Far more of a wanderer is the tropical long-tailed, long-winged, black frigate bird, which is the hawk of the sea, for it hovers about the flocks of fishing birds and forces them to disgorge their catch, which it appropriates as it falls. Among the birds that suffer most from its robberies are the pelicans, several species of which live close to salt water in various parts of the world, while others prefer the lakes and swamps inland. We have two common species in the United States, the white pelican, seen all over the interior of the country in summer, and the brown, which is southern and maritime; both are gregarious not only in their annual migrations but in their breeding, building nests on bushes in large companies. Their food is mainly fish, caught both by diving and by scooping them up as they swim. The well-known peculiarity of the pelican is the bag of naked skin that hangs from the underside of the bill, and serves as a receptacle for the catch; when it is filled the bird returns to its resting place to consume its food at leisure, or to open wide its mouth and allow its nestlings to pick out the contents of the bag.
All the foregoing are mainly marine and have short legs and webbed feet, used principally in swimming; but we now come to the fresh-water "waders"—the herons, bitterns, storks, ibises, and the like, whose bodies are perched on stiltlike legs, and whose habits require them to wade about in marshes and swamps in search of their miscellaneous food; hence the neck also is long and the bill straight and sharp-edged to fit it for seizing and holding the active prey by a sudden thrust. All warm and temperate countries possess herons in a great variety of species, varying in size from a bird three and one-half feet long, such as our great blue heron, to one a few inches only in length; but the colors are usually light and prevailingly bluish or greenish; while the marsh-loving bitterns are streaked brown. Some are pure white, as is our elegant egret, which has been all but exterminated in the United States by men who kill it in the breeding season, when the beautiful plumes that then adorn its back are at their best, and are marketable as ornaments for hats and military shakos. Every plume bird so killed means the loss of a family of young. Herons are shy, solitary birds, as a rule, nesting on trees in remote swamps in "rookeries" to which they return year after year from their winter retreats in the tropics; and they get their food, which includes every sort of living thing they can find, mostly by standing motionless in the water until it comes near enough to be picked up by a swift stroke.
The storks are similar birds, but with rather heavier bodies and a way of standing erect, and of holding the head straight out in flight (the herons draw it back by curving the neck), which distinguishes them. They are white and black as a rule, and mainly Oriental or African, no typical species occurring in the United States. Storks are more inclined to search the land for food than are the herons, and an Egyptian species is locally called "a bird of blessing," because it cleans the villages, while the stately "adjutant" of India is carefully protected as a similar scavenger. The most familiar of the storks, however, is the white one that in Europe nests on the roofs of houses, chimney tops and similar places, and is generally regarded with an affection that has been expressed in many a poem and story. Ibises are much like storks, the common "sacred" ibis of Egypt probably owing its religious distinction to its fondness for lizards and snakes—a service highly appreciated in that country. Several ibises inhabit America, one of which is not uncommon along the border of the Gulf of Mexico, while another is noted for the splendid scarlet of its plumage. In the same family is the beautiful spoonbill of our Gulf Coast, whose name refers to the spatulate expansion of the end of the beak. Its richly roseate hue is reproduced in the dress of the flamingos, that need not be described.
| FLAMINGOS |
| (Phœnicopterus ruber) |
We pass from the flamingos to the ducks by an intermediate form—the curious chahas and horned screamers of northern South America—large, turkeylike birds, often tamed and made of service on country places, where they guard the poultry against hawks and other enemies.
The ducks are a cosmopolitan family (Anatidæ) of about 200 species, divisible into five groups, namely, mergansers, river ducks, marine ducks, geese and swans. These have many features in common, one of which is that in the early autumnal molt all the wing quills drop out at once, so that for a time none of them is able to fly. The mergansers, sheldrakes, or "saw bills," are fish eaters, catching their prey under water, where they move expertly, by means of the narrow, tooth-studded bill that reminds us of the ichthyornis. They frequent rivers, and most of them prefer rushing streams. Of our three species two breed only in the Far North, the third on the Pacific slope. During the winter they resort to a marine life in warmer latitudes. The river ducks (Anatinæ) are distinguished from the seafaring ducks (Fuligalinæ) not only by their preference for inland lakes and marshes, but by the fact the hind toe bears no lobe, while in the sea ducks it is somewhat webbed and functional. This group includes such well-known species as the mallard, black duck, gadwall, widgeon, baldpate, teals, shoveler, pintail, and the exquisite wood duck, to speak of American species alone. The mallard and wood duck breed all over the continent, the latter having the peculiarity of making its nest in trees, but the others rarely nest south of Canada, except among the mountains of the Pacific slope.
The seafaring ducks in North America also include several species that are found on inland bays and salt marshes, such as Chesapeake Bay and its borders, and do not limit their migratory routes to the seacoast, but fly overland. Such are the redhead and canvasback, the scaups and golden-eyes and the ringneck; but the eiders, the scoters, and some others are truly oceanic. Most of these breed in the Far North, always nesting on the ground, as is the rule of the whole family, except the golden-eyes, which choose hollows in stumps and trees. None of the ducks lays spotted eggs.
While among the ducks the male is likely to wear, at least in the breeding season, more gayly colored plumage than the female—often of extraordinary beauty—among the geese both sexes are alike, and either white throughout, as in most of our species, or brown or gray, with more or less black, as in the brants, and in our common "wild" or Canada goose. Geese are far more terrestrial than ducks and visit the land to nip the herbage, young corn, or cereals; in California doing serious damage to growing crops. All our species breed in arctic lands except the Canada goose, which still makes its nest in the northern parts of the United States and throughout Canada; and most of them spend the winter south of our country. They represent to most persons the idea of bird migration. "We see the living wedge of long-necked birds," says Chapman, "passing high overhead; the unbroken sound waves bring the sonorous 'honks' with unexpected distinctness to our ears; and we receive an impressive lesson in the migration of birds. They are embarked on a journey of several thousand miles, but they come and go as surely as though they carried chart and compass."
As these geese are larger than the ducks, so the swans surpass the geese in size and are indeed the largest of water birds. The eight species are distributed all over the world, everywhere frequenting fresh waters alone; and all are white except a black-headed Argentine species, and the wholly black swan of Australia. Before the discovery of this Australian curiosity a black swan was the proverbial rara avis—something incredible! Swans live mainly on weeds and roots pulled up from the bottom, but also eat snails, and so forth. Two species, the whistling and the trumpeter swans, belong to the American fauna, but both are now rare.
[CHAPTER XXIV]
VULTURES, FALCONS AND GAME BIRDS
The so-called "birds of prey" include three quite distinct groups, the American "vultures," the hawk and eagle tribe, and the fish hawks. All agree in having strong, hook-pointed beaks, in many cases with a toothlike point on the cutting edge of the upper mandible, and covered at the base by a fleshy "cere"; and in having claws of great strength termed "talons." This catlike armament, adapted to seizing and holding living prey, and tearing its flesh, indicates the predacious nature and practice of the tribe, but it is developed to its fullest extent only in the falcons and powerful eagles, since a large part of the order are carrion-feeders or catch nothing larger than grasshoppers. Among the carrion-feeders are the condor of the Andes, and his almost extinct cousin the California condor, which are the largest flying birds in the world. Near relative to them are the turkey buzzard and carrion crow of our Southern States, besides some tropical species. The vultures of the Old World are, as a rule, big birds inhabiting mountainous and desert places, and capable of overcoming almost any disabled or weak animal. A small one that in North Africa plays the rôle of town scavenger, as does our turkey buzzard, is famous under the Egyptian name of "Pharaoh's chicken." The partial nakedness of the head, often accompanied by a great neck-ruff, is a characteristic of all these birds.
The lammergeier of the Alps and eastward to India connects in its structure and habits the vultures (Vulturidæ) with the real predatory family (Falconidæ), in which are placed the hundreds of species of buzzards, harriers, hawks, eagles and sea eagles, that subsist by killing and eating every kind of creature that it is within the power of each one to overcome. The bulk of their prey consists of small rodents; and in pursuing them they rid the land of vast numbers of little gnawers most injurious to agriculture; it should be the business of every farmer and orchardist to learn to recognize the three or four fierce little poultry-catching falcons in his locality, and refrain from killing any other sort of hawk.
It is a hopeless task to give any detailed description of the game birds, which are world-wide in their distribution and practically of the greatest importance to mankind, for in this group are found the originals of our domestic poultry (the jungle fowls of India), and the quails, partridges, grouse, pheasants, turkeys, curassows, and many more of hardly more interest to the naturalist than to the sportsman. The sportsman is willing to count the toothsome rails as "game" when he goes after them in the marshes of the middle coastal States. They are plain-colored birds that run about amid the salt grass and reeds, and are an interesting example of adaptation to this special station in life, for their bodies are notably compressed, so that a rail can slip through a narrower space than any other bird of its size; hence the proverb: "Thin as a rail." A common species in Europe is known in literature as "corn crake"; and American relatives, the gallinules of fresh-water marshes, go by the name of "mud hens." The rails belong to the crane family, which includes many large tropical birds besides our own two kinds of cranes, both becoming rare in the United States.
Good sport and delicate fare are afforded also by the great tribe of "shore birds"—plovers, yellowlegs, curlews, snipe, and the various sandpipers that feed along the seashores or frequent the inland marshes of every part of the world, nowhere more numerously than along our much embayed eastern coast. The plovers are especially interesting, and one of them, the noisy killdeer, is familiar all over the country, breeding in upland fields, where four brown and spotted eggs are laid in a little hollow of the open ground, plover fashion. Another notable species, the golden plover, is a cosmopolitan, and a remarkable migrant, journeying from its arctic breeding place to the tropics, not only overland, but across thousands of miles of ocean, as from Nova Scotia direct to Bermuda, and Alaska to Hawaii. The crested "lapwing" of Europe is another famous species. The plovers have short bills and live on insects; but the sandpipers that in greenish or brown-streaked coats flit along the shores pick up a more miscellaneous fare from the edge of the sea and on exposed tide flats. Here too, are the very longed-legged "stilts," the phalaropes with lobes along their toes like a grebe, the curlews, with their long, upcurved bills, the willets that alarm all the rest by their cries as soon as they espy a gunner, the big, gray godwits and many others. Various snipes form a group of small, swift fliers that haunt boggy land, where they probe the mud with long bills furnished with nerves of great delicacy at the tip by which they can feel the hidden worms buried in the mud that are their favorite fare; and one of them is the swamp-haunting woodcock, beloved of gourmands on both sides of the ocean. Europe and Asia have several other kinds of birds in this class not known here, such as the coursers, and the Egyptian "ziczac" that now and then picks the crocodile's teeth, and is almost the same as the historic lapwing, so familiar in Scotland.
[CHAPTER XXV]
FROM GULLS TO KINGFISHERS
Our scientific arrangement introduces next the gull family, followed by a series of groups that seems to the layman most miscellaneous. The gulls are a world-wide family of sea birds, seen also near bodies of water in the interior of continents, especially northward, which live on fish and floating edibles. They are mostly glistening white, often marked with black about the head and wings, except the big brownish skuas that live by robbing other gulls of their catch and their nests of young. A very distinct group in the family are the smaller terns, whose slender forms, long wings, and graceful flight give them the suitable name of "sea swallows." Another distinct lot is that of the low-flying black "skimmers." All these birds normally breed on sandbanks near shore, laying four handsomely variegated eggs in a mere shallow of earth, but a good many nest in colonies on the margin of fresh-water lakes. The gulls serve well as scavengers, but are not good to eat.
Related to the gulls, but very different in appearance, are the small, dark-colored, quaint auks, guillemots and puffins of northern coasts, that look like miniature penguins, for they stand erect on two big feet. They are fishers, with great skill in swimming and diving, and breed in companies of thousands, sometimes, on the ledges of the sea-fronting cliffs of Labrador, northern Scotland, Alaska, and Arctic islands. The extinct "great auk" of the North Atlantic coasts was a giant of this race.
Passing the sand grouse of Africa and Russia, we come to the pigeons, represented in a bewildering variety of forms in every part of the world. The United States has several species—the common wood dove, or mourning dove, the extinct "wild pigeon," once here in millions, the banded pigeon of the Pacific Coast, and several kinds of ground doves in the southwest. The rock dove, which is the original of the domestic varieties, is still wild in Europe, together with several other species; and the Orient abounds in representatives of the family, some of them large and extremely handsome, especially in the division called fruit pigeons. To this family belonged that famous bird of the past, the "dodo" of Mauritius.
There follow two big groups, the cuckoos and plantain eaters, and the parrots, which together have the peculiarity of two toes in front and two behind, instead of the customary three toes in front and one, or perhaps none, behind; the woodpeckers have the same "yoke-toed" arrangement, but are distinct otherwise. The cuckoos are mainly Oriental and very varied, although all show the slender form, long tail, and long curved beak that we see in our two American species, the black-billed and yellow-billed; the most aberrant one in our country is the queer, lizard-catching road runner of southern California. None of the cuckoos seems a good nest maker. The nests of our common ones are loose platforms of twigs, and both species often drop eggs in each other's cradles; but they, in common with almost all the other cuckoos of the world, do at least incubate their eggs and care for the nestlings, instead of leaving that task to some foster parent, as does the similar cuckoo of Europe. The most extraordinary feature of this parasitic habit is the fact that the cuckoo often, if not always, first lays its egg in any convenient place, and then, taking it in its beak, carries it to another bird's nest and puts the egg into it. This accounts for the frequent finding of a cuckoo's egg in nests into which so large a bird could not have crept.
To record the fact that about 500 different kinds of parrots are catalogued will be a sufficient explanation of their dismissal with a few general remarks. The larger number and most striking examples—the great cockatoos for instance—belong to Australia and the Malayan islands, but the Indian region, Africa, and tropical America abound in parrots. Probably the northernmost of the whole family is our Carolina parakeet, which formerly ranged in summer even to the Great Lakes, but now is almost exterminated even from the great swamps of the Gulf Coast. Of the two kinds most often seen in cages—a custom that is almost prehistoric in antiquity—the gray parrot is African, and the green or green and yellow "Amazons" come from South America.
Parrots are gregarious, nest in holes in trees, although a few live in holes in the ground or among loose rocks, and feed on all sorts of vegetable productions, including some very hard fruits cracked in their powerful bills, as is the habit of the gorgeous macaws of Central and South America. The lories of Australia are provided with tongues brushlike at the tip, and besides eating seeds they lick the honey out of the blossoms of the eucalyptus and other flowering trees, and in so doing effect the cross-fertilization of these trees in a country which has no bees to do that service.
Passing the brilliant rollers of the Old World, and the motmots and little gemlike todies of the New, we come to the extensive tribe of kingfishers, of which our blue and white example is a very modest specimen—but the only one we have, while 150 other species are counted in the rest of the world, most of them in the Austro-Malayan region and in Africa. They vary immensely in size, colors, food and habits. A large section are not "fishers" at all, but dwell in wooded places, and subsist on insects caught on the wing, and on reptiles, mice, etc., like birds of prey. Few groups are so diversified and entertaining as this one. Related to them are the bee-eaters, hoopoes, hornbills and others that bring us to the owls, a suborder of which contains the great nightjar family to which our whippoorwills and nighthawks belong, with the swifts and humming birds as near relations. Then come the woodpeckers, much alike all over the world (but absent from Australia), followed by the gorgeous trogons of Mexico and some other tropical beauties.
[CHAPTER XXVI]
PASSERINE BIRDS
We have now run through the list of all the orders of birds except the last and largest—the "passerine" birds, the ordinary songsters of the fields and woodlands of the northern hemisphere. There are fifty families contained in the order. Here, among our North American migratory birds are to be found the kingbirds, pewees and other "tyrant" flycatchers; the larks of our western plains and eastern seashore; that sprite of the Rocky Mountain brooks, the ouzel; the waxwings, the butcher birds; the pretty greenish vireos that build those exquisite, cup-shaped hanging nests made of grapevine bark and spider's silk; and the swallows that become so friendly every summer about barns, paying rent by diligent service in insect killing. Then there is that interesting little group of small and cheerful climbers, the nuthatches, chickadees, and creepers, that rid trees of hosts of injurious insects which they dig out of crevices of the bark as they scramble up and down the trunks, some of them continuing the good work all through the winter. These have their counterparts in Europe, for in respect of our common song birds, as of the birds of prey and game birds, the avifauna of Europe and North America is virtually one. The differences are mainly in the few representatives of tropical groups that visit northern countries in summer, those of Europe partaking of the African or Indian families, while we have wandering species from groups that are properly inhabitants of Mexico and southward. Such, in fact, are our few humming birds, hundreds of species of which belong to the American tropics (and none to the Old World), our two tanagers, members of a very large tropical family, and our blackbirds and orioles, far more numerous in species south of the United States.
While we have many delightful vocalists, the best singers of all our birds are no doubt the thrushes, and that is true of thrushes elsewhere, for the European blackbird and mavis, the celebrated nightingale, the solitaire—both that of the West Indies and that of our northern Pacific Coast—and several noted musicians in the Orient, are of this melodious family. Which is the best singer of them all will never be settled, for the citizen of each country likes best that to which he is most used; but to Americans nothing can be better than the evening carol of the wood thrush, the serene hymnlike music of the hermit, or the sweet and wavering call of the veery. Yet in the South, where these northern thrushes are rarely heard at their best, the palm is given to the mocking bird, which, like the northern brown thrasher, rivals all in turn by simulating their notes in a liquid melody that, especially when heard in the calm of a moonlit summer evening, seems of surpassing beauty.
[CHAPTER XXVII]
THE BEASTS OF THE FIELD—SOME PRIMITIVE TYPES
We have now arrived at the highest rank in the scale of animal life—the four-footed, hair-clad, milk-nursed denizens of our woods and fields—the subclass Mammalia, mammals.
These are the "animals" of popular speech, but accuracy requires a more distinctive expression, for every living thing not a plant is an "animal." Unfortunately no such distinctive term exists in our language, and hence we must borrow from the Latin the word "mammal" for this group. It is correct, easy to remember, and there is no reason why it should not be used popularly as well as scientifically. It is good, because it is exact, and expresses the one great distinction which separates mammals from all other animals—the feeding of the young on milk secreted by the mother. The milk-producing glands were called in Latin "mammæ," whence our word "mammal" and the technical term Mammalia—animals that suckle their young.
Another peculiarity of the group is the coat of hair—persistently growing threads of horny substance produced from the skin in greater or less abundance and of varying quality and color. Its chief purpose appears to be that of keeping the body warm; and, as in the case of the feathers clothing birds, it enables the blood to rise to and maintain a temperature much higher than that of the air; hence the mammals are "warm-blooded." This condition, gradually acquired, stimulated their activity and hence their brain development, the result of which is a higher degree of intelligence than is manifested, as a class, by any other animals, and a moving cause of their progress to the highest plane of organic evolution.
The history of the evolution of the Mammalia may be traced back to obscure beginnings in the Triassic, the oldest of the three divisions of the Secondary or Mesozoic era. Just preceding that time there flourished a group of reptiles, the Theromorpha, whose skull, teeth, and forelimbs were very like those of a modern beast of prey; and zoölogists consider it "altogether probable" that the origin of the mammalian branch must be looked for among their number. It is not doubted, however, that true mammals, although very small and inconspicuous, existed throughout the whole Mesozoic era, despite the fact that the world at that time was filled with ravenous reptiles. Indeed, it is believed that their steady development was an important agency in destroying the reptile population, largely by eating their eggs. At any rate, before the end of the Mesozoic era the two grand divisions of Mammalia, Prototheria and Eutheria, had become established; and also the two primary divisions of the latter, the Marsupials and the Placentals, had been separated. Then came that extraordinary change in the physiography of the globe that marked the end of Mesozoic conditions and introduced those of the succeeding era named Tertiary. In the broader and higher land areas and the drier and more invigorating climate that followed, producing a vegetation tending constantly to become like that of the present, mammals found increasingly favorable conditions, and became the dominant race of animals.