« EelmineJätka »
side of the structure with lumps of earth. Certain Warblers , into the nest of the dupe, and after the necessary incuba(Aedon and Thamnobia) for some unascertained reason in tion by the fond fool of a foster-mother the interloper sucvariably lay a piece of snake's slough in their nests--to cessfully counterfeits the heirs, who perish miserably, repel, it has been suggested, marauding lizards who may victims of his superior strength. . The whole process has thereby fear the neighbourhood of a deadly enemy, The been often watched, but the reflective naturalist will pause clay-built edifices of the Swallow and Martin are known to ask how such a state of things came about, and there is to everybody, and the Nuthatch plasters up the gaping not much to satisfy his enquiry. Certain it is that some mouth of its nest-hole till only a postern large enough for birds whether by mistake or stupidity do not unfrequently entrance and exit, but easy of defence, is left. In South lay their eggs in the nests of others. It is within the knowAmerica we have a family of birds (Furnariidæ) which ledge of many that Pheasants' eggs and Partridges' eggs are construct on the branching roots of the mangrove globular often laid in the same nest, and it is within the knowledge ovens, so to speak, of mud, wherein the eggs are laid and of the writer that Gulls' eggs have been found in the nests the young hatched. The Flamingo erects in the marshes of Eider-Ducks, and vice versa; that a Redstart and a Pied it frequents a mound of earth some two feet in height, Flycatcher will lay their eggs in the same convenient hole with a cavity atop, on which the hen, having oviposited, —the forest being rather deficient in such accommodation; sits astride with dangling legs, and in that remarkable atti- that an Owl and a Duck will resort to the same nest-box, tude is said to perform the duty of incubation. The set up by a scheming woodsman for his own advantage ; and females of the Hornbills, and perhaps of the Hoopoes, that the Starling, which constantly dispossesses the Green submit to incarceration during this interesting period, the Woodpecker, sometimes discovers that the rightful heir of males immuring them by a barrier of mud, leaving only a the domicile has to be brought up by the intruding tenant. small window to admit air and food, which latter is assidu- In all such cases it is not possible to say which species is ously brought to the prisoners.
so constituted as to obtain the mastery, but it is not diffiOccasional But though in a general way the dictates of hereditary cult to conceive that in the course of ages that which was departure instinct are rigidly observed by birds, in many species a driven from its home might thrive through the fostering
remarkable degree of elasticity is exhibited or the rule of of its young by the invader, and thus the abandonment
habit is rudely broken. Thus the noble Falcon, whose of domestic habits and duties might become a direct gain
ordinary eyry is on the beetling cliff, will for the con to the evicted householder. This much granted, all the
venience of procuring prey condescend to lay its eggs on rest will follow easily enough, but it must be confessed
the ground in a marsh, or appropriate the nest of some that this is only a presumption, though a presumption
other bird in a tree. The Golden Eagle, too, remarkably which seems plausible if not likely.
adapts itself to circumstances, now rearing its young on a
precipitous ledge, now on the arm of an ancient monarch
of the forest and again on a treeless plain, making a
humble home amid grass and herbage. Herons also shew The pains bestowed by such Birds (incomparably the
the same versatility and will breed according to circum- most numerous of the Class), as build elaborate nests and
stances in an open fen, on sea-banks or (as is most usual) the devices employed by those that, not doing so, display no
on lofty trees. Such changes are easy to understand little skill in providing for the preservation of their produce,
The instinct of finding food for the family is predomin-invite some attention to the eggs which they lay. This
ant, and where most food is there will the feeders be attention will perhaps be more cheerfully given when we Birds gathered together. This explains, in all likelihood, the think how many naturalists, not merely ornithologists, have breeding associated bands of Ospreys or Fish-Hawks, which in been first directed to the study of the animal kingdom by in socie
North America breed (or used to breed) in large companies the spoils they have won in their early days of birds' nesting. Birds' ties
where sustenance is plentiful, though in the Old World the With some such men the fascination of this boyish pursuit nesting. same species brooks not the society of aught but its mate.
has maintained its full force even in old age-a fact not so Birds there are of eminently social predilections. In much to be wondered at when it is considered that hardly Europe, excepting Sea-fowls—whose congregations are any branch of the practical study of Natural History brings universal and known to all—we have perhaps but the the enquirer so closely in contact with many of its secrets. Heron, the Fieldfare, and the Rook, which habitually flock It is therefore eminently pardonable for the victims of this during the breeding-season ; but in other parts of the devotion to dignify their passion by the learned name of world many birds unite in company at that time, and in “Oology,” and to bespeak for it the claims of a science. none possibly is this habit so strongly developed as in the Yet the present writer-once an ardent follower of the Anis of the Neotropical Region, the Republican Swallow practice of birds'-nesting, and still on occasion warming to of North America, and the Sociable Grosbeak of South its pleasures—must confess to a certain amount of disapAfrica, which last joins nest to nest until the tree is said pointment as to the benefits it was expected to confer on to break down under the accumulated weight of the Systematic Ornithology, though he yields to none in his Its uses common edifice. 1
high estimate of its utility in acquainting the learner with Parasitic In the strongest contrast to these amiable qualities is the most interesting details of bird-life—without a know
the parasitic nature of the Cuckows of the Old World and ledge of which nearly all systematic study is but work the Cow-birds of the New, but this peculiarity of theirs is that may as well be done in a library, a museum, or a disso well known that to dwell upon it would be needless. secting-room, and is incapable of conveying information to Enough to say that the egg of the parasite is introduced the learner concerning the why and the wherefore of such
or such modifications and adaptations of structure. To i There are not many works on nidification, for “ Caliology" or the some--and especially to those who are only anatomists— study of nests has hardly been deemed a distinct branch of the science. A good deal of instructive matter (not altogether free from error) will
this statement may seem preposterous, but it is in truth be found in Rennie's Architecture of Birds (London : 1831), and there
no such thing. What engineer can be said to understand is Mr Wallace's most interesting dissertation, "A Theory of Birds' his business if he knows not the purpose to which the Nests,” originally published in the Journal of Travel and Natural machines he makes are to be applied and is unacquainted History (1868, p. 73), and reprinted in his Contributions to the Theory with their mode of working? We may investigate thoof Natural Selection (London : 1870). Mr Andrew Murray's and the Duke of Argyll's remarks on this essay are contained in the same
roughly the organs of any animal, we may trace from volume of the Journal named (pp. 137 and 276).
the earliest moment in which they become defined, and
watch them as they develop to maturity, we may compre- | who early in the eighteenth century explored, chiefly for
hend the way in which every part of a complicated struc- this kind of investigation, the valley of the Danube-a
ture is successively built up, but if we take not the trouble region at that time, it is almost unnecessary to remark,
to know their effect on the economy of the creatnre we as utterly unknown to naturalists. But there is no need to
naturalists have done but half our task and abandon our catalogue the worthies of this study. As they approach
labour when the fulness of reward is coming upon us. our own day their number becomes far too great to tell,
The field-naturalist, properly instructed, crowns the work and if very recently it has seened to dwindle the reason is
of the comparative anatomist and the physiologist, though probably at hand in the reflection that most of the greatest
without the necessary education he is little more than an prizes have been won, while those that remain to reward
empiric, even should he possess the trained cunning of the the aspiring appear to be just now from one cause or another
savage on whose knowledge of the habits of wild animals almost out of reach. Perhaps at the present time the Birds-
depends his chance of procuring a meal.
of-Paradise and their allies form the only group
coveries Perhaps the greatest scientific triumph of oologists lies recognized distinctiveness and extent of whose eggs we
in their having fully appreciated the intimate alliance of know absolutely nothing—though there are important iso-
the Limicolæ (the great group of Snipes and Plovers) with lated forms, such as Atrichia, Heterolocha, and others, con-
the Gavice (the Gulls, Terns, and other birds more distantly cerning the eggs as well as the breeding habits of which
connected with them) before it was recognized by any pro- our ignorance is absolute, and the species of many families
fessed taxonomist,-L'Herminier, whose researches have that have hitherto defied the zeal of oologists are very
been much overlooked, excepted; though to such an one was
These last, however, though including some
given the privilege of placing that affinity beyond cavil common and some not very uncommon British birds, possess
(Huxley, Proc. Zool. Soc. 1867, pp. 426, 456-458; cf. Ibis, in a general way comparatively little interest, since, the
1868, p. 92). In like manner it is believed that oologists eggs of their nearest allies being well known, we cannot
first saw the need of separating from the true Passeres expect much to follow from the discovery of the recluses,
several groups of birds that had for many years been un and it is only to the impassioned collector that the obtain-
hesitatingly associated with that very uniforın assemblage. ing of such desiderata will afford much satisfaction.
Diffidence as to their own capacity for meddling with mat The first thing which strikes the eye of one who be- Varied
ters of systematic arrangenient may possibly have been the holds a large collection of egg-shells is the varied hues of hues of
cause which deterred the men who were content to brood the specimens. Hardly a shade known to the colourist is eggs.
over birds' eggs from sooner asserting the validity of the not exhibited by one or more, and some of these tints have
views they held. Following the example furnished by the their beauty enhanced by the glossy surface on which they
objects of their study, they seem to have chiefly sought to are displayed, by their harmonious blending, or by the
hide their offspring from the curious eye—and if such was pleasing contrast of the pigments which form markings as
their design it must be allowed to have been admirably often of the most irregular as of regular shape. But it Forms of
successful. In enthusiastic zeal for the prosecution of their would seem 'as though such markings, which a very small markings.
favourite researches, however, they have never yielded to, amount of observation will shew to have been deposited
if they have not surpassed, any other class of naturalists. on the shell a short time before its exclusion, are primarily
If a storm-swept island, only to be reached at the risk of and normally circular, for hardly any egg that bears mark-
life, held out the hope of some oological novelty there was ings at all does not exhibit some spots of that form, but
the egg-collector (Faber, Isis, xx. pp. 633-688; Proctor, that in the progress of the eggs through that part of the
Naturalist, 1838, pp. 411, 412). Did another treasure oviduct in which the colouring matter is laid on many of
demand his traversing a burning desert (Tristram, Ibis, them become smeared, blotched, or protracted in some par-
1859, p. 79, or sojourning for several winters within the ticular direction. The circular spots thus betoken the
wildest wastes of the Arctic Circle (Wolley, Ibis, 1859, deposition of the pigment while the egg is at rest, the blurred
pp. 69-76; 1861, pp. 92-106; Kennicott, Rep. Smithson. markings show its deposition while the egg is in motion,
Inst. 1862, pp. 39, 40), he endured the necessary hard and this motion would seem often to be at once onward
ships to accomplish his end, and the possession to him of and rotatory, as indicated by the spiral markings not un-
an empty shell of carbonate of lime, stained or not (as the commonly observable in the eggs of some Birds-of-prey
case might be) by a secretion of the villous membrane of and others—the larger end of the egg (when the ends differ
the parent's uterus, was to him a sufficient reward. Taxo- in form) making way for the smaller. At the same time
nomers, however, have probably been right in not attach- the eggs of a great number of birds bear, beside these last
ing too great an importance to such systematic characters and superimposed markings, more deeply-seated stains,
as can be deduced from the eggs of birds, but it would generally of a paler and often of an altogether different
have been better had they not insisted so strongly as they hue, and these are evidently due to some earlier dyeing
have done on the infallibility of one or another set of char- process. The peculiar tint of the ground-colour, though Ground-
acters, chosen by themselves. Oology taken alone proves commonly superficial, if not actually congenital with the colour.
to be a guide as misleading as any other arbitrary method formation of the shell
, would appear to be suffused soon of classification, but combined with the evidence afforded after. The depth of colouring whether original or superby due study of other particularities, whether superficial or vening is obviously dependent in a great measure on the deep-seated, it can scarcely fail in time to conduct us to constitution or bodily condition of the parent. If a bird, an ornithological arrangement as nearly true to Nature as bearing in its oviduct a fully-formed egg, be captured, that. we may expect to achieve.
egy will speedily be laid under any circumstances of inThe first man of science who seems to have given any convenience to which its producer shall be subjected, but special thought to oology, was the celebrated Sir Thomas such an egg is usually deficient in coloration-fright and Browne, of Norwich, who already in 1681, when visited by John Evelyn (from whose diary we learn the fact), had ? That the larger end is protruded first was found on actual experiassigned a place in his cabinet of rarities to a collection of ment hy Mr Bartlett, Superintendent of the Gardens of the Zoological The next we hear of is that Count of Marsigli Society, to be the case commonly, but as an accident the position may
be sometimes reversed, and this will most likely account for the occa
sional deposition of mar ings on the sinaller instead of the larger end 1 A small proportion of carbonate of magnesia and phosphate of as not unfrequently shown in eggs of the Sparrow-hawk (Accipiter lime and magnesia also enters into its composition.
nisus). The head of the chick is always formed at the larger end.
captivity having arrested the natural secretions. In like Oorhodeine, Oocyan, Banded Oocyan, Yellow Ooxanthine,
manner over excitement or debility of the organs, the con Rufous Ooxanthine, a substance, giving narrow absorption-
sequence of ill health, give rise to much and often very bands in the red, the true colour of which he has not yet Effect of curious abnormality. It is commonly believed that the been able to decide, and lastly Lichenoxanthine. It would
older a bird is the more intensely coloured will be its eggs, be out of place here to particularize their chemical propercolour.
and to some extent this belief appears to be true. Certain ties, and it is enough to say that they are closely connected
Falconidæ, which ordinarily lay very brilliantly-tinted eggs, either with hæmoglobin or bile-pigments, and in many
and are therefore good tests, seem when young unable to respects resemble the latter more than do any
group secrete so much colouring-matter as they do when older, of colouring-matters, but do not actually agree with them. and season after season the dyes become deeper, but there The first is perhaps the most important of all the seven, is reason to think that when the bird has attained its full because it occurs more or less in the shells of so great a vigour improvement stops, and a few years later the inten- number of eggs that its entire absence is exceptional, and sity of hue begins to decline. It would be well if we had it is of a very permanent character, its general colour being more evidence, however, in support of this opinion, which of a peculiar brown-red. The second and third seem when is chiefly based on a series of eggs of one species—the pure to be of a very fine blue, but the spectrum of the Golden Eagle (Aquila chrysaetus), in the writer's possession, former shows no detached bands, while that of the latter among which are some believed on good grounds to have has a well-marked detached absorbent-band near the red been the produce in the course of about twelve years of end, though the two are closely related since they yield the one and the same female. The amount of colouring-matter same product when oxidized. The fourth and fifth subsecreted and deposited seems notwithstanding to be gene- stances supply a bright yellow or reddish-yellow hue, and
rally a pretty constant quantity_allowance being made for the former is particularly characteristic of eggs of the Varieties individual constitution, but it often happens—especially Emeus (Dromæus), giving rise when mixed with oocyan in the same in birds that lay only two eggs—that nearly all the dye wil to the fine malachite-green which they possess, while the .
be deposited on one of these, leaving the other colourless ; latter has only been met with in those of the Tinamous it seems, however, to be a matter of inconstancy which of (Tinamidce), in which it should be mentioned that oorhothe two is first developed. Thus of two pairs of Golden deine has not been found, or perhaps in those of a CasseEagles' eggs also in the possession of the writer, one speci- wary (Casuarius), and when mixed with oocyan produces a inen of each pair is nearly white while the other is deeply peculiar lead-colour. The sixth substance, as before stated, coloured, and it is known that in one case the white egg has not yet been sufficiently determined, but it would seem was laid first and in the other the coloured one. When birds in combination with others to give them an abnormally lay many mottled, and a fortiori plain, eggs, there is gene- browner tint; and the seventh appears to be identical with rilly less difference in their colouring, and though no two one which occurs in greater or less amount in almost all ein hardly ever be said to be really alike, yet the family classes of plants, but is more especially abundant in and resemblance between them all is obvious to the practised characteristic of lichens and fungi. There is a possibility eye. It would seem however to be a peculiarity with some however of this last being in part if not wholly due to the species--and the Tree-Sparrow (Passer montanus) which growth of minute fungi, though Mr Sorby believes that luys five or six eggs may be taken as a striking example- some such substance really is a normal constituent of the that one egg should always differ remarkably from the rest shell of eggs having a peculiar brick-red colour. That of the clutch. In addition to what has been said above gentleman is further inclined to think that oorhodeine is as to the deposition of colour in circular spots indicating in some way or other closely related to cruentine, being a pause in the progress of the egg through one part of the probably derived from the red colouring-matter of the blood oviduct, it may be observed that the cessation of motion at by some unknown process of secretion, and likewise that that time is equally shewn by the clearly defined hair-lines there is some chemical relation between the oocyans and or vermiculations seen in many eggs, and in none more
the bile. commonly met with than in those of the Buntings (Ember The grain of the egg-shell offers characters that deserve Grain of izide). Such markings must not only have been deposited far more consideration than they have received until lately, the shell while the egg was at rest, but it must have remained mo when the attention of Herr von Nathusius having been tionless until the pigment was completely set, or blurred directed to the subject by some investigations carried on
instead of sharp edges would have been the result.1 -by Dr Landois 3 and Herr Rudolf Blasius, 4 he has brought Nature of The composition of this pigment has long excited much out a series of remarkable papers in which he has arrived pigment.
curiosity, and it has been commonly and rather crudely at the conclusion that a well-defined type of shell-structure ascribed to secretions of the blood or bile, but very recently belongs to certain families of birds, and is easily recognized unexpected light has been shed upon the subject by the under the microscope. In some cases, as in the eggs of researches of Mr Sorby (Proc. Zool. Soc. 1875, p. 351), certain Swans and Geese (Cygnus olor and C. musicus, who, using the method of spectrum-analysis, has now ascer Anser cinereus and A. segetum) even specific differences are tained the existence of seven well-marked substances in the apparent. The bearing of these researches on classificacolouring-matter of eggs, to the admixture of which in cer tion generally is of considerable importance and must be tain proportions all their tints are due. These he names taken into account by all future taxonomers.
cannot enter into details, it must suffice to remark that 1 The principal oological works with coloured figures are the follow
the grain of the shell is sometimes so fine that the surface
ing:- Thienemann, Fortpflanzungsgeschichte der gesammten Vögel (4to, is glossy, and this is the case with a large number of Pi-
Leipzig: 1845); Lefèvre, Atlas des aufs des oiseaux d'Europe (8vo, carice, where it is also quite colourless and the contents of
Paris: 1845); Hewitson, Coloured Illustrations of the Eggs of British their eggs seen through the semi-transparent shell give an
Birds (8vo, Ed. 3, London: 1856); Brewer, North American Oology (4to,
Washington : 1859); Taczanowski, Oslogia Ptaków Polskich (8vo,
Warszawa: 1862); Bädeker, Die Eier der Europäischen Vögel (fol. Leip 3 Zeitschr. für wissensch. Zoologie, xv. pp. 1-31,
zig: 1863); Wolley, Ootheca Wolleyana (8vo, London: 1864)--some of Op. cit. xvii. pp. 480-524.
which have never been completed ; but a great number of rare eggs 5 Op. cit. xviii. pp. 19-21, pp. 225-270, xix. Pp. 322–348, xx. pp.
are also figured in various journals, as the Proceedings of the Zoologi- | 106-130, xxi. pp. 330-335. A summary of these will be found in
cal Society, Naumannia, the Journal für Ornithologie, and The Ibis. Journ. für Ornith. 1871, pp. 241-260, and the subject has been con.
? cf ke, Naumannia, 1858, pp. 393-397, and C. Leconte, Revue tinued in the same periodical for 1872, pp. 321-332, and 1874, pp.
ct wasin de Zoologie, 1860, pp. 109-205.
opalescence of great beauty; but among the Tinamous are taken, remarks :-"The reason of this great disparity is,
(T'inamide) colour is invariably present and their opaque however, obvious; the eggs of all those birds which quit
eggs present the appearance of more or less globular balls the nest soon after they are hatched, and which are conse-
of highly-burnished metal or glazed porcelain. Most birds quently more fully developed at their birth, are very large.”
lay eggs with a smooth shell, such as nearly all the Gavice, It must be added, though, that the number of eggs to be
Limicolæ, and Passeres, and in some groups, as with the covered at one time seems also to have some relation to
normal Gallince, this seems to be enamelled or much their size, and this offers a further explanation of the fact
polished, but it is still very different from the brilliant just mentioned with regard to the Snipe and the Partridge
surface of those just mentioned, and nothing like a definite —the former being one of those birds which are constant
line can be drawn between their structure and that in in producing four, and the latter often laying as many as
which the substance is dull and uniform, as among the a dozen--for the chicks of each run as soon as they release
Alcidæ and the Accipitres. In many of the Ratito the themselves from the shell.
surface is granulated and pitted in an extraordinary man Incubation is performed, as is well known, by the female Incubation.
ner,' and in a less degree the same feature is observable in of nearly all Birds, but with most of the Passeres and many
the eggs of some other birds, as the Storks (Ciconiidae). others the male seems to share her tedions duties, and
Many Water-fowls, and particularly the Ducks (Anatide), among the Ratitæ, apparently without exception, the cock
lay eggs with a greasy or oleaginous exterior, as the col takes that office wholly on himself. There are a few groups
lector who wishes to inscribe his specimens with marks of or perhaps species in which the same practice is suspected
their identity often finds to his inconvenience; but there to obtain-certain of the Limicolæ for instance, the Godwits
are other eggs, as those of the Anis (Crotophaga), the (Limosa), the Phalaropes (Phalaropus), and the Dotterel
Grebes (Podicipedidæ), and all of the Steganopodes, except (Eudromias morinellus)--and in these it is to be remarked
Phaeton, which are more or less covered with a cretaceous that the hen is larger and more brightly coloured than her
film, often of considerable thickness and varied by cal- mate. Owing to the unfortunate neglect of those who
have the opportunity of making the needful observations
In form eggs vary very much, and this is sometimes ob- the period of Incubation has been ascertained in compara-
servable in examples not only of the same species but even tively few birds, and it is here possible to deal with that
from the same mother, yet a certain amount of resemblance subject only in the most vague and general language. It
is usually to be traced according to the natural group to may be asserted that most of the smaller Passeres of Europe
which the parents belong. Those of the Owls (Strigidæ) hatch their young in about thirteen days, but in a few
and of some of the Picariæ—especially those which lay the species the term is believed to be shortened to ten or eleven
glossy eggs above spoken of-are often apparently spheri- days, while in the largest of that Order, the Raven, it is
cal, though it is probable that if tested mathematically lengthened to some twenty-one days. This also is the
none would be found truly so-indeed it may be asserted period which the Barndoor-fowl ordinarily takes, but the
that few eggs are strictly symmetrical, however nearly they Pheasant, though so very nearly allied, takes about twenty-
may seem so, one side bulging out, though very slightly, eight. Most Water-birds, so far as is known, and the
more than the other. The really oval form, with which smaller Birds-of-prey seem to require as long a time, but
we are most familiar, needs no remark, but this is capable in the Swan incubation is protracted to six weeks. The
of infinite variety caused by the relative position and pro- temperature of the air is commonly credited with having
portion of the major and minor axes. In nearly all the something to do either in hastening or retarding exclusion
Limicolo and some of the Alcide the egg attenuates very from the egg, but to what extent, or even whether justly
rapidly towards the smaller end, sometimes in a slightly so or not, seems in the absence of precise experiments to
convex curve, sometimes without perceptible curvature, be doubtful. Certain birds occasionally begin brooding as
and occasionally in a sensibly concave curve.
soon as the first egg is laid,4 and this plan unquestionably having this pyriform shape are mostly those of birds which has its advantages, since the offspring being of different invariably lay four in a nest
, and therein they lie with their ages thereby become less of a burthen on the parents which
points almost meeting in the centre and thus occupying as have to minister to their wants, while the fostering warmth
little space as possible and more easily covered by the of the earlier chicks can hardly fail to aid the development
brooding parent. Other eggs as those of the Sand-Grouse of those which are unhatched, during the absence of father
(Pterocleidce) are elongated and almost cylindrical for a and mother in search of food; but most birds, and it need
considerable part of their length terminating at each end scarcely be said, all those the young of which run from their
obtusely, while eggs of the Grebes (Podicipedidae) which birth, await the completion of the clutch before sitting is
also have both ends nearly alike but pointed, are so wide begun. The care bestowed, by almost every species, on
in the middle as to present a biconical appearance.2 the infant-brood, is proverbial, and there is hardly any
The size of eggs is generally but not at all constantly in extremity of danger which one at least of the anxious
proportion to that of the parent. The Guillemot (Alca parents will not incur to ward off injury from their pro-
troile) and the Raven (Corvus corax) are themselves of about geny.
equal size; their eggs vary as ten to one.
(Scolopar gallinago) and the Blackbird (Turdus merula)
differ but slightly in weight, their eggs remarkably. The The more or less protracted business of reproduction
eggs of the Guillemot are as big as those of an Eagle; and being ended there forthwith follows in the case of nearly
those of the Snipe equal in size the eggs of a Partridge all Birds a process of the most vital consequence to them.
(Perdix cinerea). Mr Hewitson, from whom these instances This is the Moult or shedding of their old and often wea-
ther-beaten feathers to be replaced by an entirely new suit.
1 It is curious that Ostriches' eggs from North Africa are to be
It is probably the severest strain to which bird-life is ex-
readily distinguished from those from the Cape of Good Hope by their
smooth ivory-like surface, without any punctures, whereas southern posed, and, to judge from its effects on our domesticated
specimens are rough as though pock-marked (Ibis, 1860, p. 74), yet no pets, produces a greater mortality than an occasional want
difference that can be deemed specific has as yet been established be-
tween the birds of the north and of the south.
Hewitson, op. cit. Introd. p. X.
? A great deal of valuable information on this and other kindred * This seems to be very often the case with the Owls, but if the
subjects is given by Des Murs, Traité général d'Oologie ornithologique writer's observation is not mistaken the habit is not constant even
(8vo, Paris: 1860).
with the same individual bird.
of proper or even any food does. Important however as flight for a season, during which time they generally seek
are its bearings on every individual of the whole Class, the the shelter of chick, aquatic herbage, and it is further to
subject is one whicḥ has been sadly neglected by ornitho. be particularly remarked that the males of most of two
logical writers and, with one exception, we are not aware sections of the family (Anatinæ and Fuligulinæ) at the
of any connected series of observations on Moult within the same period lose the brilliantly-coloured plumage which
whole range of their literature. The structure and mode commonly distinguishes them and “go into eclipse," as
of growth of feathers has been very well studied and de- Waterton happily said, putting on for several weeks a
scribed by several investigators, and must be especially dingy garb much resembling that of the other sex, to
treated in introducing the subject of Pterylography—or resume their gay attire only when, their new quills being
the disposition of the various plumed patches on the bird's grown, it can be safely flaunted in the open air. Here Additiona'
body-which, having been found to be a most useful auxili we have the first instances of Additional Moult to be men moult.
ary in Classification, is deferred until that comes to be tioned. Another is not less interesting, though ornitholo-
discussed under the article “ ORNITHOLOGY." For the pre- gists must confess with shame that they have not sufficiently
sent we have briefly to consider the different phases which investigated it. This is that of the Ptarmigan (Lagopus
the process of Moulting offers.
mutus), both sexes of which not only moult after the breedAnnual As a general rule all Birds are subject to an annual ing-season is over into a grey suit, and then again as Joult. Moult, and this as above stated, commonly begins immedi- autumn passes away into their snowy.winter-clothing, but,
ately on the close of the breeding-season, but, as will be divesting themselves of this last in spring, then put on
explained further on, there are some which undergo in each a third and most distinctive dress-these changes,
addition a second or even a third partial change of plum- however, do not extend to the quills either of the wings or
age, and it is possible that there may be others still more tail.4
exceptional, our information respecting these, however, is The number of Birds which undergo a more or less entire Variation
too meagre to make it worth while saying anything here Double Moult is very considerable, and the peculiarity is of moult
about them. It must be acknowledged that with regard not always characteristic of families or even, unless in a
to the great majority of forms we can only judge by analogy, restricted sense, of genera. Thus while the Garden-Warbler
and though it may well be that some interesting deviations (Sylvia salicaria) is said to moult twice in the year the
from the general rule exist of which we are altogether Blackcap (S. atricapilla) does so but once.
The same may
ignorant, yet when we consider that the Ratitæ, so far as be said of the Emberizidæ, in which family both practices
observed, moult exactly in the same manner as other birds, 2 seem to obtain, but on the other hand the distinction in
the uniformity of the annual change may be almost taken this respect between the Larks (Alaudide) and the Pipits
(Anthince), belonging to the family Motacillidæ, appears, so It is not intended here to describe the way in which a far as our knowledge goes, to be invariable, though the habits
feather dies and a new one succeeds it, nor need we compare and general appearance of both groups are so much alike--. Necessity the process of moulting with the analogous shedding of the the Alaudidæ moulting but once and the anthinæ, conformof moult. hair in Mammals or of the skin in Reptiles. Enough for our ing to the practice of the normal Motacillidæ (Motacillina),
present purpose to see that such renovation is required in twice a year—the quills, be it understood, excepted. But
Birds, which nearly all have to depend upon their quills for it would be impossible here to give more than these few
the means of locomotion and hence of livelihood. It is examples, and indeed we scarcely know anything of the
easy to understand that durable as are the flight-feathers, subject outside of groups belonging to the Northern
they do not last for ever and are besides very subject to hemisphere.5
accidental breakage, the consequence of which would be In a large number of species the Additional Moult is very Partial
the crippling of the bird. It is obviously to provide against partial, being often limited to certain portions of the plumage, noult.
what in most cases would be such a disaster as this last and it is yet an unsolved problem how far some of the
that we find the remiges, or quill-feathers of the wings, to changes to be observed are due to actual Moult and how
be always shed in pairs. They drop out not indeed abso- far to the alteration of colour in the feathers themselves, as
lutely at the same moment, though this sometimes seems also the way by which this alteration of colour is produced,
to happen, but within a few days of each other, and, whether, as certainly happens in many instances
, by the
equilibrium being thus preserved, the power of flight is dropping off of the “ barbicels”—the fine filaments that
but slightly deteriorated by their temporary loss. The fringe the “barbicels” which are arranged on the upper
same may be observed in a less degree, since there is less surface of each “barb” composing the web of the feather
need of regularity, with the rest of the plumage, as a little or in some other manner. With either of these last
attention to any tame bird will show, and the new feathers considerations we need not now concern ourselves. It is
grow at an almost equal rate. In the young of most unquestionable that there are innumerable species of birds,
species the original quills are not shed during the first year, the males at least of which put forth in spring decorative
nor in the young of many does there seem to be an entire plumes unknown at any other season, and it would appear
moult during that time, but in the typical Gallince, which that in the majority of them the feathers which before
are able to fly at a very early age, often before they are clothed the parts whence the newly-donned ornaments
one-third grown, the original quilis, being proportioned to grow are doffed to make room for these paraphernalia of
the duties required of them, are shed before the bird has marriage.
attained its full size and are succeeded by others that serve it The subject of Additional Moult is thus intimately con-
when it has reached maturity. In the Duck-tribe (Anatidæ), nected with the seasonal adornment of Birds, and as that
however, we have a very singular exception to what has
been above stated. Most of these birds shed their quill-
3 One species, Micropterus cinereus, seems never to regain the power
of flight thus lost. Cf. Cunninghain, Proc. Zool. Soc. 1871, p. 262. feathers all at once, and become absolutely incapable of * Macgillivray (Brit. Birds, i. p. 196, London: 1837; and Nat.
Hist. of Deeside, p. 405, London: 1855) thought there were four
* This is a valuable paper by Herr Meves, of Stockholm (Efvers. moults in this species, but that seems to be one too many. Herr Meves
K. Vet. Akad. Förhandl. 1854, p. 258), of which a German transla (loc. cit.) and the Abbé Caire (Rev. Zool. 1854, p. 494) independently
tion with some additions by the author may be found in Journ. für made the discovery of the Triple Moult, and almost simultaneously
Ornith. 1855, pp. 230-238.
announced it. Cf. Gloger, Journ. für Orn. 1856, p. 461.
* For the knowledge of this fact the writer is indebted to the vast 5 The fullest list as yet published is that of Herr Meves (ut supra),
experience of Mr Bartlett.
but it is not entirely free frem error.