Part 5

Warm-blooded Vertebrates, which breathe by lungs, are covered with feathers, have no teeth but a horny beak, and lay hard-shelled eggs, which are hatched by the warmth of their body. They are adapted for movement in the air, though not all to the same degree. The fore limbs are modified into wings, in which, however, the parts found in Mammals can be recognized. We distinguish in the first place a small thumb, and then in most cases a two-jointed forefinger and a small second finger. _Secondary quills_ (Fig. 28, BB) are attached to the ulna, and _primary quills_ (A, 1–10) to the two metacarpals and the finger joints, while the thumb bears the bastard wing (C). The tail feathers, or _rectrices_, are attached to the last joint of the tail. The body is clothed with stiff, tolerably long _contour feathers_, which conceal the soft short _down_ from view. The bones are hollow and filled with air. Their cavities are connected with _air-sacs_, which are found in all parts of the body, and fill themselves with air from the lungs when the bird begins to fly. In this way its specific gravity is reduced. The body firm, especially the hinder part of it, which is almost immovable; the neck, which may consist of many vertebræ (even as many as twenty-two), can, on the contrary, be turned in many directions. Birds walk entirely on their toes; the metatarsals are fused with one of the rows of tarsals into a “_tarsus_” bone. Tarsus and toes are covered with horny scales.

A bird’s egg (Fig. 29) consists of a germinal disc (_h_) from which the young bird develops, and which rests on the yolk, made up of substances serving for the nutriment of the developing bird: the yellow (_a_) and the white (_b_) yolk, as well as the albumen (_c_, _c_^1, “white of egg”) in which lie two twisted cords (_chalazæ_),—finally of protective structures: the shell-membrane (_e_) and the calcareous shell (_f_); _g_ is the air-chamber.

[Illustration:

FIG. 28.—Wing of the Buzzard. ]

[Illustration:

FIG. 29.—A Bird’s Egg. ]

When the young escape from the egg, they are either able to at once look after themselves more or less, at least to look for their food,—in which case they can see and are clothed with feathers at hatching (_precocious young_; _e.g._ fowls, ducks, gulls, and pewits),—or the young remain some time in the nest, as they are, to begin with, both blind and naked, and in this case they are fed for some time by the parents (_nestlings_; _e.g._ birds of prey, sparrows, nightingales, pigeons). In the frigid and temperate zones most species of birds do not remain in their native country after the breeding season; those which go south in the autumn are termed _migrants_; while birds which do not migrate, but remain in the district where they have bred, are known as _residents_ (sparrow, jay, magpie). _Gipsy migrants_ execute more or less extensive wanderings, influenced by want of food or other causes (woodpecker, titmouse, golden-crested wren, tree-creeper). The travels of such birds are not, like those of migrants, undertaken at a definite time of year, or in definite directions (N., S.), but many of their species collect together in large flocks for the purpose of wandering, like migrants.

The following orders are usually distinguished:

[Illustration:

FIG. 30.—The Eagle Owl (_Otus maximus_). ]

I. _Raptores_ (Birds of Prey), II. _Scansores_ (Climbers), III. _Passeres_ (Singing Birds), IV. _Gyrantes_ (Doves), V. _Rasores_ (Scratchers), VI. _Grallatores_ (Waders), VII. _Natatores_ (Swimmers), VIII. _Cursores_ (Running Birds).

The Order Cursores includes the ostrich-like birds, and will not here receive further notice.

ORDER: Raptores (BIRDS OF PREY).

Upper beak hooked, covered with a skin (_cere_) at its base; four toes possessing strong claws, and provided with pads in their under side (Fig. 31); wings powerful. Birds of prey live in pairs, and breed once a year in nests composed of pieces of wood and branches. The young are nestlings (p. 51). Sight keen. These birds feed almost exclusively on vertebrates, principally mammals and birds. An idea of their food can be gained by examination of their “pellets”—roundish balls composed of the indigestible parts of their food, and disgorged from twelve to twenty hours after feeding. Two groups are distinguished—_diurnal_ and _nocturnal_ birds of prey. The first (Figs. 31, 32) have a laterally flattened head, eyes directed laterally, and tolerably stiff feathers. The nocturnal forms (“owls,” Figs. 30, 33) have a large head, flattened in front, with large eyes facing to the front, soft plumage, and hair-like feathers on the toes, of which two are directed forwards, one backwards, and one outwards. The radiating feathers round the eye constitute a “veil.”

[Illustration:

FIG. 31.—Head and Foot of Falcon. ]

Predominatingly harmful (from killing domestic mammals) are the following species occurring in Britain: the =Sea Eagle= (_Haliaëtus albicilla_), the =Golden Eagle= (_Aquila chrysaëtus_), the =Peregrine Falcon= (_Falco peregrinus_), the =Merlin= (_F. œsalon_), the =Hobby= (_F. subbuteo_), the =Sparrow Hawk= (_Accipiter nisus_), the =Kite= (_Milvus regalis_), the =Goshawk= (_Astur palumbarius_), the =Harriers= (_Circus cyaneus_ and _C. cinerarius_), and the =Honey Buzzard= (_Pernis apivorus_). The last effects damage by catching honey bees.

[Illustration:

FIG. 32.—The Golden Eagle (_Aquila chrysaëtus_). ]

Useful in the main, being destroyers of field-voles, are the following: the =Kestrel= (_Falco tinnunculus_), the =Buzzard= (_Buteo vulgaris_), the =Barn Owl= (_Strix flammea_, Fig. 33), the =Brown Owl= (_S. aluco_), the =Little Owl= (_Athene noctua_), a casual, the =Short-eared= or =Woodcock Owl= (_Otus brachyotus_), the =Long-eared Owl= (_O. vulgaris_), and the =Eagle Owl= (_Otus maximus_, Fig. 30), a rare visitor.

A bird of prey cannot simply be classed as harmful or useful; a species mainly injurious may sometimes destroy a field vole or a destructive bird, while a useful species may sometimes attack domestic poultry. Game-preserving is destructive of almost all the indigenous diurnal birds of prey, and of the owls to a less extent.

ORDER: Scansores (CLIMBERS).

Birds with two toes directed forwards and two backwards. The young are nestlings. Here belong toucans, parrots, cuckoos, and woodpeckers. The first two groups are limited to the tropics; woodpeckers are only of importance in the culture of fruit trees and in forestry. I describe briefly—

[Illustration:

FIG. 33.—The Barn Owl (_Strix flammea_). ]

The =Cuckoo= (_Cuculus canorus_, Fig. 34). Fourteen inches long, tail eight inches. The yellowish beak is slightly curved; feet yellow. Back blue-grey in old birds, brownish in young ones. Belly white with dark transverse lines. Ten tail quills, flecked with white. Shy; flies like a bird of prey. The female lays her eggs at intervals of about fourteen days, and cannot therefore hatch them out herself. She lays the egg on the ground, and then takes it in her bill to the nest of a small bird which feed its young with insects (wagtail, grasshopper warbler, nightingale, robin, lesser whitethroat, wren, lark). The cuckoo’s egg is generally hatched by the foster parent, and the true young often do not come out from the egg, owing to lack of warmth; or, if hatched, they are thrown out later on by the much larger, rapidly developing young cuckoo. Every cuckoo, therefore, is so far harmful that it costs the lives of several insect-eating birds. But it far more than compensates for this by destroying insects. It is especially beneficial to fruit-tree culture and forestry, since it eats an enormous number of caterpillars; but in late summer it comes frequently from the woodland into the fields, and then eats the caterpillars of the cabbage white, cabbage moth, and silver Y moth, surface caterpillars, and the larvæ of the turnip saw-fly. It also devours mole-crickets and (naturally in the spring) cockchafers.

[Illustration:

FIG. 34.—The Cuckoo (_Cuculus canorus_). ]

ORDER: Passeres (PERCHING BIRDS).

This order is essentially constituted by all those birds with helpless young (p. 51), which do not belong to the two preceding orders or the one next following. Beak without a cere. Three toes forwardly, one backwardly directed.

Group: =Hirundinidæ= (_Swallows_).

With short flat beak, broad at the base, with gape extending far back, and triangular as seen from above. In flight the beak is opened as widely as possible, serving for catching insects. Wings long and pointed. Feet short and weak, entirely unsuited or only poorly adapted for walking; their chief use is to enable the swallow to hold fast to different objects. Swallows fly quickly and catch insects while on the wing. The insects on which they prey are generally unimportant to agriculture and forestry; but they may also do good by catching crane flies (_Tipula_), and ribbon-footed corn flies (_Chlorops_), which often fly about our fields in enormous swarms in order to lay their eggs. All swallows are migratory birds. There belong here—

1. True =Swallows= (_Hirundo_), with forked tails; three toes directed to the front, one to the back. Here may be reckoned—=Swallow= (_H. rustica_), always broods in sheltered spots, _e.g._ inside a stable, summer-house, or verandah; =House Martin= (_H. urbica_), nests against buildings, under the eaves for example; the =Sand Martin= (_H. riparia_), breeds in the neighbourhood of streams, especially in vertical banks of loamy or coherent sandy soil, where it makes its nest at the end of a passage a yard long. The =House Martin= is shining black on the back, white on the entire under surface and rump. The =Bank Martin= is brownish grey on the back, white on the under side, with brownish-grey bands on the breast.

2. =Swifts= (_Cypselus_), with forked tails and four strong, curved, forwardly directed claws. Only one British species belongs here—the =Swift= (_Cypselus apus_), ten inches long, brownish black except for white throat, and with very long curved wings.

3. =Night-jars= (_Caprimulgus_), with tail not forked, soft plumage, large head and eyes; fly at night. One species belongs here—the =Goatsucker= (_Caprimulgus europæus_, Fig. 35), twelve inches long, grey on the upper side, spotted with blackish brown and rusty yellow, yellowish whitey grey with dark wavy lines on the under side. In the day it flies awkwardly and heavily, and usually keeps under cover; by night it flies rapidly and boldly, especially in bare spots in woods, or in gardens and on fields. It haunts especially the neighbourhood of sheepfolds and cattle in the meadows, since it always finds flies and gnats there. It also catches cockchafers and various moths.

[Illustration:

FIG. 35.—The Goatsucker (_Caprimulgus europæus_). ]

Group: =Magnirostres= (_Large-beaked Perching Birds_).

Beak strong, thick, often incurved near its apex. These birds eat almost all kinds of food, both animal and vegetable. Here belong Starlings and Raven-like Birds (crows, magpies, jays).

The =Starling= (_Sturnus vulgaris_).

Plumage black, with a violet sheen. The tips of the contour feathers, however, are white or bright yellowish. These white patches become so well marked after the autumn moult, that they almost completely cover the shining metallic black of the feathers. They gradually become smaller; in the next spring they are almost or entirely lost. Very serviceable. Devours, especially in autumn, many field snails, also cockchafer grubs, wireworms, grass caterpillars, grasshoppers, leaf-lice; also many insects destructive to fruit trees and forest trees. The starling, however, is able to do considerable damage to garden fruit trees, since it eats cherries, currants, and sometimes even pears. Starlings often settle on the backs of sheep and cows in order to pick off the vermin.

Genus: =Corvus= (_Crow-like Birds_).

Here belong—1. The =Jackdaw= (_C. monedula_), with relatively short beak and long tarsi. Black; side of the head and neck ashen grey. Breeds in holes in trees, chimneys, ruins, and towers. 2. The =Hooded Crow= (_G. cornix_); bright grey, except the head, throat, wings, and tail, which are black. Breeds in all parts of Europe east of the Elbe; occurs in Western Europe as a gipsy migrant in winter. 3. =Carrion Crow= (_C. corone_); black, beak stout and strongly bent at its end. Breeds in trees, but never (like the Rook) in large numbers together. 4. =Rook= (_C. frugilegus_); black, beak rather long; in adult specimens the head feathers are quite worn away at the base of the beak. 5. =Raven= (_C. corax_); much larger than the other species; black, beak very strong, strongly curved along its entire upper side. Nowhere in large numbers.

[Illustration:

FIG. 36.—Head of Rook (_Corvus frugilegus_). ]

_Food, Benefit conferred, and Damage done._ Ravens, and sometimes even rooks, attack lambs and sick sheep, also ducks, geese, fowls, and pigeons. Carrion crows and hooded crows rarely attack our domestic animals. All crows, however, steal the eggs of our poultry. They also injure sport, since they kill hares and rabbits, young fawns, quails, pheasants, etc. They do a little good, however, by devouring field-voles, but, as a rule, only catch the sick ones which are not able to move quickly. They do harm by destroying useful insect-eating birds, also eating their eggs and young. But as insect-eaters, they are extremely useful; they devour cockchafers, wireworms, butterflies, surface caterpillars, crane flies and their larvæ, and field snails; also many earthworms. As to the vegetable part of their food, they devour, in the first place, germinating seeds; grain, peas, beans. They also pick grain from the ear, both when ripe and, to a larger extent, when still soft; and in doing this pull down the ear so as to crack the stalk, thus causing more damage than by the mere eating. They also plunder the ripening peas, and feast upon cherries, plums, apricots, and other juicy fruits; even potatoes and turnips. All crow-like birds do some harm and some good, only the raven (which eats scarcely any insects) is to be always reckoned as an enemy.

The =Magpie= (_Pica caudata_) and =Jay= (_Garrulus glandarius_) are resident birds closely related to the crows. The first affects open tracts of land (fields, meadows, gardens) in the neighbourhood of large trees; the latter is a woodland bird. Both birds eat almost everything: grain, acorns, beechnuts, cherries, berries; cockchafers, wireworms, and similar insects; the eggs and young of useful insect-eating song-birds (such as titmice), also these little birds themselves, ducklings and chickens, young partridges, quails, pheasants, now and then field-voles. More harmful than useful.

Group: =Conirostres= (_Conical_-_beaked Perching Birds_).

Beak conical, thicker and shorter than in the species of the following group. They devour insects and seeds, a few species seeds exclusively. Here belong first the =Titmice= (_Parus_), gipsy migrants which are extremely serviceable both in fruit-tree culture and forestry. Then the =Larks= (especially the =Skylark=, _Alauda arvensis_, a resident), which nest on the ground, eating insects, seeds, and in winter even leaves; they feed their young, however, with insects. They do both good and harm, but the former mostly preponderates. In late summer and autumn, skylarks collect in flocks, and wander here and there for a long time: before this, they travel south; at this time many are caught and eaten. The male skylark sings beautifully, rising meanwhile high in the air. The =Buntings= (_Emberiza_) have a characteristic compressed and pointed beak; they seek their food on the ground in fields and meadows, and on roads. The food consists of grain and insects; but since these birds never take grains from the ear, they only do damage by picking them up at seed-time. They feed their young with insects. The damage is usually very inconsiderable, but, on the other hand, the benefit conferred is slight. (=Yellow Hammer=, _E. citrinella_, a yellow-coloured resident. The =Common Bunting=, _E. miliaria_, a grey-coloured migrant, etc.) In the family of =Finches= a number of species are included which are of small agricultural importance: _e.g._ the =Bullfinch= (_Pyrrhula vulgaris_), specially attacks fruit-tree buds in March; the =Goldfinch= (_Carduelis elegans_); the =Siskin= (_Chrysomitris spinus_); the =Lesser Redpoll= (_Linota linaria_); the =Greenfinch= (_Ligurinus chloris_). A few species, however, must be dealt with more fully, and, first,—

[Illustration:

FIG. 37.—Head of Bullfinch. ]

The two =Sparrows=,

_i.e._ the =House Sparrow= (_Passer domestica_) and the =Tree Sparrow= (_P. montana_).

=House Sparrow=: ear region bright grey. A rust-coloured or yellowish streak behind the eye. The whole throat black in the male. Wings with a yellowish white transverse band. =Tree Sparrow=: ear region black. A black streak behind the eye, a white band round the neck, and a black patch on the throat. Wings with two white transverse bands. The two sparrows are very much alike in their habits, but the house sparrow frequents more the neighbourhood of human dwellings, even in large towns. Both sparrows are mainly harmful; where seeds (especially those containing starch, _e.g._ corn) are available, they prefer this kind of food to any other; and, besides this, they chiefly bring up their young on soft unripe grain. Sparrows devour the germinating corn after seed-time, and also pick the grain from the ear, in which process they at the same time do damage by breaking down the haulms so that the grain falls out. They pick the young peas from their pods; devour, too, several juicy tree fruits, _e.g._ cherries and grapes; and destroy young garden seedlings, _e.g._ lettuce, spinach, garden flowers. The house sparrow eats more insects than the tree sparrow (among them—geometer caterpillars, injurious roller caterpillars), but leaves the most noxious kinds untouched. Both sparrows are residents, but in autumn and winter often collect together in large flocks.

The =Linnet= (_Linota cannabina_),

with grey-brown darkly spotted back. Belly whitish, tail black with broad white margins. During summer the top of the head and the breast of the male are of a beautiful red. They are often found together in flocks during September. In spring and summer they chiefly live on oil-containing seeds, and may even do some good by eating the seeds of charlock; usually, however, doing much more harm by devouring the seed of rape, flax, linseed, and hemp.

The =Chaffinch= (_Fringilla cœlebs_).

A white patch on the two outermost tail feathers and the ones next them. Wings with one white and one yellowish transverse band. Male: upper side of head and neck bluish grey, back brown, breast reddish brown. Female: back grey-brown, belly whitish, breast ash-grey. The chaffinch inhabits forests, both those of ordinary foliage trees and those consisting of conifers; it also nests in gardens and plantations. At the beginning of September the males separate from the females, and both sexes collect in large flocks which haunt gardens, avenues, and bushes. In mild winters they remain resident, but travel away if the cold is greater. The chaffinch devours oil-containing seeds by preference, but also eats starchy ones, and seeks its food on the ground. It does a great deal of damage in cornfields by picking the seeds out of the soil after they have been sown; but does not take the grain from the ear. It also eats young seedlings. But valuable services more than counterbalance the harm done. When the chaffinches in autumn fly about in large flocks in the fields, they eat an enormous number of weed seeds. The young are chiefly fed with insects, especially with caterpillars. In the spring, when the seeds have germinated and the young corn is not yet ripe, the chaffinch feeds itself also on insects.

Group: =Subulirostres= (_Awl-beaked Perching Birds_).

Beak slender, awl-shaped, round in transverse section. A fully developed organ of voice. Feed almost exclusively on insects; there are only a few species which occasionally eat seeds. A few of them, however, sometimes devour juicy fruits (cherries, bird-cherries, elder-berries, juniper-berries, grapes). The birds belonging to this group, without exception, feed their young on insects. They are of service; even those species which occasionally do damage are useful on the whole.

There belong to the Subulirostres—

The =Wagtails= (_Motacilla_), _e.g._ the =White Wagtail= (_M. alba_), usually living in the neighbourhood of water, and seeking its insect food in the fields (often behind the plough), and in pastures and gardens.

The lark-coloured =Pipits= (_Anthus_).

The =Hedge Accentor=, or “Sparrow” (_Accentor modularis_),—in garden hedges, and woods, feeding sometimes on seeds.

The following “warblers:” =Nightingale= (_Daulias luscinia_), =Robin= (_Erithacus rubecula_), =Redstart= (_Ruticilla phœnicurus_), the =Lesser Whitethroat= (_Sylvia curruca_), =Garden Warbler= (_S. hortensis_), =Willow Wren= (_S. trochilus_), =Chiffchaff= (_S. rufa_), =Reed Warblers= (_Acrocephalus streperus_ and _A. arundinacea_), etc. The last-named live among reeds and rushes on the banks of fresh waters, and eat insects which do not affect agriculture and forestry; all the other warblers are useful.

Other examples of the Subulirostres are the =Golden-crested Wren= (_Regulus cristatus_), and the =Common Wren= (_Troglodytes parvulus_), which are of service to forestry and fruit-tree culture, but not to agriculture.

[Illustration:

FIG. 38.—The Nightingale (_Daulias luscinia_). ]

Most of the native thrush-like birds (_Turdus_), _e.g._ the =Blackbird= (_T. merula_), the =Missel Thrush= (_T. viscivorus_), the =Fieldfare= (_T. pilaris_), the =Redwing= (_T. iliacus_), and the =Song Thrush= (_T. musicus_), assist the farmer by devouring noxious insects and snails; but several of them occasionally do damage by poaching on cherries, grapes, currants, etc. Some of them (_e.g._ the Song Thrush and Blackbird) breed in almost all parts of Britain, others come here only in autumn or winter.

ORDER: =Gyrantes= (DOVES).

Body strongly built, somewhat thick-set. Wings long and pointed. Beak weak, with a cere at its base; nostrils covered by gristly scales. Toes: three forwardly and one backwardly directed, free, _i.e._ without a web (as in poultry). The young are at first blind and naked. They are at first fed with a cheesy secretion of the glands of the crop; later, with grain softened in the crop. Doves always live in pairs. Nests careless, flat, of loosely arranged twigs; situated on tree-branches, rocks, and large buildings. Doves breed twice or thrice a year, laying two longish, shining white eggs.

Native British forms:—

[Illustration:

FIG. 39.—The Wood Pigeon (_Columba palumbus_). ]

1. =Wood Pigeon= (_Columba palumbus_, Fig. 39), from April to September scattered about in the woods, but after the breeding season wander about in flocks, and in winter travel further south, although many remain. It nests on horizontal branches, and feeds on seeds of fir and pine, acorns, beechnuts, also grain, peas, vetches, rape-seed,—but seeds of many weeds as well (_e.g._ those of charlock, vetchling, spurry, cleavers). When the earth is covered with snow it often eats cabbage and the leaves of winter rape, but is also of some service.

2. The =Turtle Dove= (_C. turtur_) occurs on the edges of woods, especially those consisting of coniferous trees. Nests in the trees. For _food_, _use_, and _harm_, cp. the preceding species. Steals buckwheat grains from the fields.

3. The =Rock Pigeon= (_C. livia_) is the original stock of our races of domestic pigeons. It nests, as a resident, in the Mediterranean countries; as a migrant, on the rocky parts of the coasts of Great Britain and the Orkneys, Shetlands, and Faroe Islands.

ORDER: =Rasores= (POULTRY).

Body strong, thick-set. Head small, often with naked, brightly coloured patches, with fleshy combs or with a crest of feathers. Tip of the upper beak bends over that of the lower one. No cere (cp. Doves). Wings short, rounded; flight heavy. Feet strong. Hinder toe small and usually attached to the tarsus higher up than the front toes. Claws blunt. A small web at the bases of the toes. The male of several species bears a spur on the tarsus. Birds of this order usually keep on the ground, scraping it in search of their food, which consists of seeds, berries, the green parts of plants, insects, worms, and snails. Young precocious (p. 51). Several domestic birds belong to the Rasores: pheasants, the various races of fowls, pea-fowls, guinea-fowls, turkeys.

The species living wild in Britain are game-birds. They are—the =Capercailzie= (_Tetrao urogallus_, Fig. 40), =Black Game= (_T. tetrix_), =Partridge= (_Perdix cinerea_), =Quail= (_P. coturnix_); none of them are particularly harmful or useful to agriculture.

The =Pheasant= (_Phasianus colchicus_, Fig. 41) was originally a native of the Caucasus, and shores of the Caspian Sea and Sea of Aral; it occurs wild in Central Europe. Pheasants are troublesome to the farmer, both by devouring the newly sown seed and by scratching up the fields.

[Illustration:

FIG. 40.—Male and Female Capercailzie (_Tetrao urogallus_). ]