CLASS AVES, OR BIRDS. 



There is, perhaps, no class of the animal king- 

 dom more generally interesting than birds; and 

 not without reason. Their infinite variety of form, 

 habits, and manners ; their plumage, always beauti- 

 ful, often rich and gorgeous ; their aerial endow- 

 ments ; their nidification ; their voices ; the bittern's 

 boom, the cawing of busy rooks, the cock's shrill 

 clarion, the thrilling lay of the skylark, or the rich 

 strains of philomel — nay, even the hoarse cries of 

 those that tenant moorland and morass, fen or lake, 

 or wheel in buoyant flight over the broad expanse 

 of ocean : — these all combine to throw a halo of at- 

 traction around them, heightened by associations 

 which in every mind hold an abiding sway. Who 

 sees the swallow on his first return, and dreams not 

 of spring in times long past? Who hears the 

 cuckoo's voice, and thinks not of schoolboy days, 

 ready to repeat with Wordsworth, — 



" And I can listen to thee yet, 

 And lie upon the plain.; 

 And listen till I do beget 

 That golden time again !" 



Hence it is that, although all birds are interesting, 

 the birds of our own country, albeit others are more 

 gaily attired, are the most attractive. We have 

 marked their ways ; we have watched them building 

 their nests, and rearing their brood ; their melody 

 has rung in pleasant strains on our ear, and though 

 the toilsome mid-day may have succeeded to life's 

 joyous morn, there are few who cannot recall to 

 mind some old familiar spot — and how welcome the 

 reminiscence ! — when our feelings in their fresh- 

 ness, and keenly alive to the beauties of nature, 

 revelled in all of beautiful and fair, which the 

 hand of Omnipotence has showered in profusion 

 around us. 



Before we enter fairly upon our present sub- 

 ject, to have to request attention to some prelimi- 

 naries, of no little importance, at least to those who 

 wish for information: we have arranged in our 

 pictorial museum a series of preparations by way of 

 introduction, and it is on these that we would offer 

 a few remarks. We need not say that birds (with 

 certain exceptions) are all formed" for flight ; the air 

 is their domain, and their structure expressly fits 

 them for the part assigned them in the economy of 

 nature. 



If we look at a bird, say a hawk or a pigeon, we 

 perceive the general contour of its body is boat- 

 shaped, as best adapted for counteracting the re- 

 sistance of the air, through which it has to make a 

 rapid way ; we see it clothed with feathers, and also 

 that the" anterior limbs are fashioned into wings, 

 acted upon by powerful muscles, and which, striking 

 the air, bear up the bird, and at the same time 

 propel it onwards. But there is another and less 

 palpable arrangement, which we must notice, con- 

 nected with the aerial habits of birds ; we allude to 

 the extension of the lungs by means of voluminous 

 cells. The skeleton of a bird is proportionately very 

 light, for all the larger bones, those of the limbs es- 

 pecially, are hollow, and unfilled with marrow, as 

 they are in the analogous bones of quadrupeds. Now 

 these hollow bones are reservoirs for air ; nor is this 

 all : there are various extensive membranous cavi- 

 ties, or sacs, some internal, others external, between 

 the skin and the muscles, along the throat and 

 chest, between the muscles, or along the tendons 

 of the humerus ; and these, as well as the cavities 

 of the bones, communicate immediately with the 

 lungs, of which they may be considered, in a certain 

 sense, as extensions. The lungs, themselves, do not 

 float free in the chest, as do those of Mammalia, but 

 are attached to the dorsal portion of the spine, and 

 fill up the hollows between the ribs at their junction 

 with it. The design of this cellular apparatus ap- 

 pears first, as a means of effecting a more complete 

 aeration of the blood, necessary to the vigour of the 

 muscles, especially during rapid flight, when their 

 energy is most needed and most expended, and re- 

 spiration perhaps irregularly performed ; secondly, 

 as tending to increase the relative lightness of the 

 body in the surrounding atmosphere ; for when the 

 cells are distended, not only is the surface of the 

 body enlarged, but that, by means of air, rarefied, 

 and necessarily lighter than the surrounding me- 

 dium. Having said thus much, let us turn to the 

 skeleton, Fig. 1137,. that of a hawk, and for a moment 

 contemplate it. We shall not enter into elaborate 

 details. The development of the cranium ; the 

 length and flexibility of the neck ; and the con- 

 solidation of the dorsal and pelvic bones : the os- 

 seous union of the ribs with the breast-bone, broad 

 and convex externally, with a deep central keel for 

 the attachment of the voluminous pectoral muscles ; 

 and the short caudal vertebrae, ending with a larger 

 bone, the ploughshare, which bear.s the tail-feathers, 

 might engage more explanation than our space will 

 permit. The scapulas are narrow and somewhat 

 scythe-like in form, and the shoulders are kept apart 

 by a bone analogous to our clavicles, and termed 

 the furcula, os furcatum, or merrythought, and 

 which is most developed and the strongest in birds 



of the greatest powers of flight. The scapulge are 

 united to the top of the breast-bone by clavicular or 

 coracoid bones, tending to strengthen the point to 

 which the muscular strain of the wings converges. 

 The wings consist each of a humerus, a radius, and 

 ulna, carpal or wrist bones, a thumb, metacarpal 

 bones, and the phalanges of the fingers, or their re- 

 presentatives, consisting of two joints. In fact, we 

 have a nearer approach to the human arm than we 

 find in the horse or the ox. In like manner the 

 lower limbs consist, of a femur or thigh-bone, of two 

 leg bones, viz. a tibia and fibula, more or less con- 

 solidated ; of a single metatarsal or shank bone 

 (called the leg, and usually covered with scales), to 

 which is united in general three anterior toes, and 

 a posterior, or thumb. 



Fig. 1138 represents the same skeleton lettered : 

 A, the skull : b, cervical vertebrae ; c, the dotted 

 lines indicate the extent of the anchylosed vertebrae 

 of the back; d, the caudal vertebrae, the letter is 

 placed on the ploughshare ; E, the ribs ; f, the 

 breast-bone ; g, the furcula, or merrythought ; hh, 

 the clavicular or collar-bone ; h*, the scapula, or 

 shoulder-bone ; i, the humerus; k, l, the bones of 

 the fore-arm, ulna, and radius; m, metacarpus of 

 hand ; n, phalanges of fingers: o, p, q, the pelvic 

 bones ; r, the femur or thigh-bone ; o, o, the pa- 

 tella or knee-pan ; s, the leg, tibia and fibula ; t, t, 

 the os calcis, or heel-bone ; v, v, the metatarsal 

 bones; w, w, the toes. Fig. 1139 represents the 

 bones of the wing. Fig. 1140, the bones lettered: 

 g, outline of the furcula; h*, outline of part of 

 scapula ; i, humerus, or arm-bone ; k, the ulna ; 

 l, the radius, both forming the fore-arm ; ** carpal 

 or wrist bones ; m, m, metacarpal bones ; *m, the 

 thumb ; n, n, n, the phalanges of the fingers. 



Let us now in imagination clothe our skeleton 

 with muscles and skin, and dress that skin in its 

 natural clothing of feathers. These are all arranged 

 in due order, and those of many parts, especially of 

 the wings and tail, have received names, with which 

 the student of ornithology must make himself ac- 

 quainted. Fig. 1141 represents a bird displayed to 

 show its plumage : A, a, are the primaries, or great 

 quill-feathers of the wings, which are succeeded by 

 the secondaries, and these by the f ertials, b, b ; c, c, 

 are the lesser coverts : d, d, the greater coverts ; e, e, 

 the bastard wing, or winglet ; f, f, the scapularies ; 

 g, the upper tail-coverts ; h, the under tail-coverts ; 

 i, the tail-feathers (rectrices). 



In order that the arrangement of the feathers of 

 the wings may be the better understood we refer 

 to Fig. 1142, the wing of the common buzzard, 

 stripped of all its feathers, excepting those which 

 give it power and expanse, and which are those 

 arising from the hand and the ulna, and termed 

 quill-feathers. They form two sets. The first set, 

 a, a, a, consist of those arising from the hand (meta- 

 carpus and phalanges), and constituting the most 

 important of the series, being mainly instrumental, 

 by their length and shape, their stiffness or flexi- 

 bility, in determining the character or the power of 

 their flight. They are termed the primaries, or pri- 

 mary quill-feathers, and are ten in number, but they 

 differ in form as well as in relative length. The 

 second set arise exclusively from the ulna, and are 

 termed the secondaries, or secondary quill-feathers, 

 b : they are usually shorter, broader, and less rigid 

 than the former ; their number varies. From the 

 small bone which represents the thumb, arise cer- 

 tain short stiff feathers, lying close upon the quills 

 of the primaries, and constituting the spurious wing 

 or winglet, c. Besides these, there is a group of 

 feathers, termed tertiaries, arising from the humeral 

 joint of the fore-arm, and which in many birds, as 

 the curlews, plovers, lapwings, &c, are very long, 

 forming a sort of pointed, appendage, very apparent 

 during flight : in most birds, however, they are very 

 short, or not to be discriminated from the rest of the 

 greater coverts, of which, in fact, they are a con- 

 tinuation ; hence they cannot strictly be reckoned 

 among the quill-feathers. The same observation 

 also applies to the feathers, d, attached to the upper 

 part of the humerus, and termed scapularies; these 

 lie along the sides of the back, and in many birds 

 are of great length. The position of these feathers, 

 and of the coverts, will be seen in the annexed 

 sketch, Fig. 1143, which is the expanded wing of a 

 curlew : a, a series of feathers termed the lesser 

 coverts, disposed in scale-like order, row after row, 

 on the fore-arm and carpal -joint ; they cover the 

 barrels of the quill-feathers ; below them extends a 

 series of larger feathers, b, which sweep across the 

 wing, encroaching far on the primaries, and when 

 the wing is closed usually hiding the secondaries ; 

 these are the greater coverts, of which the tertiaries 

 are to be regarded as a continuation. The under 

 surface of the wing is lined with softer feathers, 

 termed under-coverts. 



We have said that the last bone or ploughshare 

 of the caudal vertebrae, and which is more developed 

 than the others, supports the tail-feathers, the quills 

 of which are fixed in capsules ; it is also furnished 



with powerful muscles, for the purpose of acting on 

 these feathers, for they are capable of being ex, 

 panded (as in the turkey-cock) or closed, elevated 

 or depressed. The terminal joint of the tail merely 

 stripped of its feathers, is, as we know, somewhat 

 heart-shaped, owing to the muscles, which are con- 

 tiguous to the bone, and to the lateral arrangement 

 of the capsules for the reception of the quills of the 

 tail-feathers. The mechanism of the tail of the com- 

 mon fowl will convey a good idea of the subject. 

 The tail-feathers vary in size, length, shape, and 

 strength, in various groups or genera ; they vary also 

 in number ; their usual number, however, is twelve, 

 sometimes they amount to fourteen, and in the Gal- 

 linaceous tribes to eighteen, or even more. The tail- 

 feathers of the common buzzard (Fig. 1144) afford a 

 good illustration of their ordinary arrangement. Six 

 on each side are disposed one above another, and 

 they partially overlay each other, the lateral one 

 on each side being overlaid by the next in succes- 

 sion, and so on to the centre ; of the two central 

 feathers one overlays the other. The quills of the 

 tail-feathers are hidden beneath what are termed 

 the upper tail-coverts, which in some birds, as the 

 peacock, the resplendent trogon (Trogon resplen- 

 dens, Gould), &c, form long flowing plumes of ex- 

 quisite beauty. Beneath the quills of the tail- 

 feathers are covered by under tail-coverts, consisting 

 of lax feathers, and in some birds, as the marabor?, 

 forming plumes of great softness and delicacy. Oc- 

 casionally, indeed, as in the ostrich, the menura 

 superba (lyre-bird of Australia), and others, the tail- 

 feathers themselves lose their ordinary character, 

 and are soft, lax, and flowing. 



It must be evident that the shape, arrangement, 

 and texture of the feathers composing the wings 

 and tail must materially affect the flight of birds, 

 both as it respects rapidity and peculiar character. 

 Of all birds, the swift (Cypselus) and the humming- 

 birds are the most remarkable for the rapidity of 

 their aerial movements ; let us attend to the cha- 

 racter presented by their wings. 



We are at first struck with the length of this organ 

 in comparison with that of the bird itself; but°we 

 see also that its breadth is not in proportion to its 

 length, and that its general form is somewhat like 

 that of a sabre. This, however, is not all ; the wing 

 appears to consist exclusively of primary quiJl- 

 feathers, so greatly are these developed, and so 

 small, comparatively, are the secondaries : the first 

 primary quill - feather is the longest, the others 

 shorten in gradual order, so that the wing is pointed. 

 Now we may here observe that a pointed form of 

 wing is essential to rapidity of flight ; we see this 

 principle exemplified in the true falcon, in the 

 pigeon, in the swallow, the pratincole, birds of 

 great powers of aerial progression. In a pointed 

 wing the first or second quill-feather is always the 

 longest, but sometimes the second and third are 

 equal. In a pointed wing the primaries greatly ex- 

 ceed the secondaries. 



To revert, however, to the wing of the humming- 

 bird, there is something in the texture of the 

 feathers composing it which must not be over- 

 looked. A rapid flight supposes a succession of 

 smart blows upon the ah, which it is evident cannot 

 be given by yielding, downy plumes. Now the 

 feathers composing the primaries in the humming- 

 bird consist of a thick, elastic, taper shaft, in some 

 species developed to an extraordinary degree at the 

 base, as in the blue-throated sabre-wing (Campy- 

 lopterus latipennis, Swains.1 : the vane on each side 

 of the shaft is narrow, Arm, and rigid, as if made of 

 a thin plate of burnished metal ; this appearance is 

 produced by the minuteness of the plumelets of 

 which the vane is composed, and by their closeness 

 to each other, and the firmness with which they are 

 united together. The wings thus present a firm 

 resistance to the air, and, as they are rapidly agi- 

 tated, produce a humming sound. The wings o.f the 

 falcon, pigeon, &c, though not composed of feathers 

 so rigid nor so metal-like in structure as in the 

 humming-bird, are nevertheless very beautifully 

 adapted as regards the texture and elasticity of the 

 primaries for velocity ; and we may set it down as 

 a rule, that wherever a long and pointed wing is 

 found, the primaries will be firm and elastic. The 

 wings of birds of rapid flight are seldom very con- 

 cave beneath, — on the contrary, they are almost flat, 

 when extended ; and this flatness, while it contri- 

 butes to the velocity of motion as the bird sweeps 

 along, destroys the power of a direct upward 

 ascent, which is possessed in far greater perfection 

 where the wings are at once ampje a«nd concave. 

 The falcon, in order to soar, is obliged to sweep 

 round in circles, or to fly against the wind, and he 

 thus rises obliquely, on the same principle as is 

 shown in aflat piece of tile or an oyster-shell thrown 

 smartly against the wind. 



Wings somewhat rounded, concave, ample, and 

 composed of stiff and well-formed quill- feathers, 

 while inferior in some points as organs of flight, are 

 superior in others ; they enable their possessor to soar 



