Chapter V: Domestic Pigeons (2)

Besides the several breeds now described, three or four other very
distinct kinds existed lately, or perhaps still exist, in Germany and
France. Firstly, the Karmeliten, or Carme Pigeon, which I have not
seen; it is described as of small size, with very short legs, and with
an extremely short beak. Secondly, the Finnikin, which is now extinct
in England. It had, according to Moore's[297] treatise, published in
1735, a tuft of feathers on the hinder part of the head, which ran down
its back not unlike a horse's mane. "When it is salacious it rises over
the hen and turns round three or four times, flapping its wings, then
reverses and turns as many times the other way." The Turner, on the
other hand, when it "plays to the female, turns only one way." Whether
these extraordinary statements may be trusted I know not; but the
inheritance of any habit may be believed, after what we have seen with
respect to the Ground-tumbler of India. MM. Boitard and Corbie describe
a pigeon[298] which has the singular habit of sailing for a
considerable time through the air, without flapping its wings, like a
bird of prey. The confusion is inextricable, from the time of
Aldrovandi in 1600 to the present day, in the accounts published of the
Draijers, Smiters, Finnikins, Turners, Claquers, &c., which are all
remarkable from their manner of flight. Mr. Brent informs me that he
has seen one of these breeds in Germany with its wing-feathers injured
from having been so often struck together; but he did not see it
flying. An old stuffed specimen of a Finnikin in the British Museum
presents no well-marked character. Thirdly, a singular pigeon {157}
with a forked tail is mentioned in some treatises; and as
Bechstein[299] briefly describes and figures this bird, with a tail
"having completely the structure of that of the house-swallow," it must
once have, existed, for Bechstein was far too good a naturalist to have
confounded any distinct species with the domestic pigeon. Lastly, an
extraordinary pigeon imported from Belgium has lately been exhibited at
the Philoperisteron Society in London,[300] which "conjoins the colour
of an archangel with the head of an owl or barb, its most striking
peculiarity being the extraordinary length of the tail and
wing-feathers, the latter crossing beyond the tail, and giving to the
bird the appearance of a gigantic swift (Cypselus), or long-winged
hawk." Mr. Tegetmeier informs me that this bird weighed only 10 ounces,
but in length was 151/2 inches from tip of beak to end of tail, and 321/2
inches from tip to tip of wing; now the wild rock-pigeon weighs 141/2
ounces, and measures from tip of beak to end of tail 15 inches, and
from tip to tip of wing only 263/4 inches.

I have now described all the domestic pigeons known to me, and have added a few others on reliable authority. I have classed them under four Groups, in order to mark their affinities and degrees of difference; but the third group is artificial. The kinds examined by me form eleven races, which include several sub-races; and even these latter present differences that would certainly have been thought of specific value if observed in a state of nature. The sub-races likewise include many strictly inherited varieties; so that altogether there must exist, as previously stated, above 150 kinds which can be distinguished, though generally by characters of extremely slight importance. Many of the genera of the Columbidae, which are admitted by ornithologists, do not differ in any great degree from each other; taking this into consideration, there can be no doubt that several of the most strongly characterised domestic forms, if found wild, would have been placed in at least five new genera. Thus, a new genus would have been formed for the reception of the improved English Pouter: a second genus for Carriers and Runts; and this would have been a wide or comprehensive genus, for it would have admitted common Spanish Runts without any wattle, short-beaked Runts like the Tronfo, and the improved English Carrier: a third genus would have been termed for the Barb: a fourth for the Fantail: and lastly, a fifth for the short-beaked, not-wattled pigeons, such as Turbits {158} and short-faced Tumblers. The remaining domestic forms might have been included in the same genus with the wild rock-pigeon.

_Individual Variability; Variations of a remarkable nature._

The differences which we have as yet considered are characteristic of distinct breeds; but there are other differences, either confined to individual birds, or often observed in certain breeds but not characteristic of them. These individual differences are of importance, as they might in most cases be secured and accumulated by man's power of selection; and thus an existing breed might be greatly modified or a new one formed. Fanciers notice and select only those slight differences which are externally visible; but the whole organisation is so tied together by correlation of growth, that a change in one part is frequently accompanied by other changes. For our purpose, modifications of all kinds are equally important, and, if affecting a part which does not commonly vary, are of more importance than a modification in some conspicuous part. At the present day any visible deviation of character in a well-established breed is rejected as a blemish; but it by no means follows that at an early period, before well-marked breeds had been formed, such deviations would have been rejected; on the contrary, they would have been eagerly preserved as presenting a novelty, and would then have been slowly augmented, as we shall hereafter more clearly see, by the process of unconscious selection.

I have made numerous measurements of the various parts of the body in
the several breeds, and have hardly ever found them quite the same in
birds of the same breed,--the differences being greater than we
commonly meet with in wild species. To begin with the primary feathers
of the wing and tail; but I may first mention, as some readers may not
be aware of the fact, that the number of the primary wing and tail
feathers in wild birds is generally constant, and characterises, not
only whole genera, but even whole families. When the tail-feathers are
unusually numerous, as for instance in the swan, they are apt to be
variable in number; but this does not apply to the several species and
genera of the Columbidae, which never (as far as I can hear) have less
than twelve or more than sixteen tail-feathers; and these numbers
characterise, with rare exception, whole sub-families.[301] The wild
rock-pigeon has twelve tail-feathers. With {159} Fantails, as we have
seen, the number varies from fourteen to forty-two. In two young birds
in the same nest I counted twenty-two and twenty-seven feathers.
Pouters are very liable to have additional tail-feathers, and I have
seen on several occasions fourteen or fifteen in my own birds, Mr. Bult
had a specimen, examined by Mr. Yarrell, with seventeen tail-feathers.
I had a Nun with thirteen, and another with fourteen tail-feathers; and
in a Helmet, a breed barely distinguishable from the Nun, I have
counted fifteen, and have heard of other such instances. On the other
hand, Mr. Brent possessed a Dragon, which during its whole life never
had more than ten tail-feathers; and one of my Dragons, descended from
Mr. Brent's, had only eleven. I have seen a Baldhead-Tumbler with only
ten; and Mr. Brent had an Air-Tumbler with the same number, but another
with fourteen tail-feathers. Two of these latter Tumblers, bred by Mr.
Brent, were remarkable,--one from having the two central tail-feathers
a little divergent, and the other from having the two outer feathers
longer by three-eighths of an inch than the others; so that in both
cases the tail exhibited a tendency, but in different ways, to become
forked. And this shows us how a swallow-tailed breed, like that
described by Bechstein, might have been formed by careful selection.

With respect to the primary wing-feathers, the number in the Columbidae,
as far as I can find out, is always nine or ten. In the rock-pigeon it
is ten; but I have seen no less than eight short-faced Tumblers with
only nine primaries, and the occurrence of this number has been noticed
by fanciers, owing to ten flight-feathers of a white colour being one
of the points in Short-faced Baldhead-Tumblers. Mr. Brent, however, had
an Air-Tumbler (not short-faced) which had in both wings eleven
primaries. Mr. Corker, the eminent breeder of prize Carriers, assures
me that some of his birds had eleven primaries in both wings. I have
seen eleven in one wing in two Pouters. I have been assured by three
fanciers that they have seen twelve in Scanderoons; but as Neumeister
asserts that in the allied Florence Runt the middle flight-feather is
often double, the number twelve may have been caused by two of the ten
primaries having each two shafts to a single feather. The secondary
wing-feathers are difficult to count, but the number seems to vary from
twelve to fifteen. The length of the wing and tail relatively to the
body, and of the wings to the tail, certainly varies; I have especially
noticed this in Jacobins. In Mr. Bult's magnificent collection of
Pouters, the wings and tail varied greatly in length; and were
sometimes so much elongated that the birds could hardly play upright.
In the relative length of the few first primaries I have observed only
a slight degree of variability. Mr. Brent informs me that he has
observed the shape of the first feather to vary very slightly. But the
variation in these latter points is extremely slight compared with what
may often be observed in the natural species of the Columbidae.

In the beak I have observed very considerable differences in birds of
the {160} same breed, as in carefully bred Jacobins and Trumpeters. In
Carriers there is often a conspicuous difference in the degree of
attenuation and curvature of the beak. So it is indeed in many breeds:
thus I had two strains of black Barbs, which evidently differed in the
curvature of the upper mandible. In width of mouth I have found a great
difference in two Swallows. In Fantails of first-rate merit I have seen
some birds with much longer and thinner necks than in others. Other
analogous facts could be given. We have seen that the oil-gland is
aborted in all Fantails (with the exception of the sub-race from Java),
and, I may add, so hereditary is this tendency to abortion, that some,
although not all, of the mongrels from the Fantail and Pouter had no
oil-gland; in one Swallow out of many which I have examined, and in two
Nuns, there was no oil-gland.

The number of the scutellae on the toes often varies in the same breed,
and sometimes even differs on the two feet of the same individual; the
Shetland rock-pigeon has fifteen on the middle, and six on the hinder
toe; whereas I have seen a Runt with sixteen on the middle and eight on
the hind toe; and a short-faced Tumbler with only twelve and five on
these same toes. The rock-pigeon has no sensible amount of skin between
its toes; but I possessed a Spot and a Nun with the skin extending for
a space of a quarter of an inch from the fork, between the two _inner_
toes. On the other hand, as will hereafter be more fully shown, pigeons
with feathered feet very generally have the bases of their _outer_ toes
connected by skin. I had a red Tumbler, which had a coo unlike that of
its fellows, approaching in tone to that of the Laugher: this bird had
the habit, to a degree which I never saw equalled in any other pigeon,
of often walking with its wings raised and arched in an elegant manner.
I need say nothing on the great variability, in almost every breed, in
size of body, in colour, in the feathering of the feet, and in the
feathers on the back of the head being reversed. But I may mention a
remarkable Tumbler[302] exhibited at the Crystal Palace, which had an
irregular crest of feathers on its head, somewhat like the tuft on the
head of the Polish fowl. Mr. Bult reared by accident a hen Jacobin with
the feathers on the thigh so long as to reach the ground, and a cock
having, but in a lesser degree, the same peculiarity: from these two
birds he bred others similarly characterised, which were exhibited at
the Philoperisteron Club. I bred a mongrel pigeon which had fibrous
feathers, and the wing and tail-feathers so short and imperfect that
the bird could not fly even a foot in height.

There are many singular and inherited peculiarities in the plumage of pigeons: thus Almond-Tumblers do not acquire their perfect mottled feathers until they have moulted three or four times: the Kite-Tumbler is at first brindled black and red with a barred appearance, but when "it throws its nest feathers it becomes almost black, generally with a bluish tail, and a reddish colour on the inner webs of the primary wing feathers."[303] {161} Neumeister describes a breed of a black colour with white bars on the wing and a white crescent-shaped mark on the breast; these marks are generally rusty-red before the first moult, but after the third or fourth moult they undergo a change; the wing-feathers and the crown of the head likewise then become white or grey.[304]

It is an important fact, and I believe there is hardly an exception to the rule, that the especial characters for which each breed is valued are eminently variable: thus, in the Fantail, the number and direction of the tail-feathers, the carriage of the body, and the degree of trembling are all highly variable points; in Pouters, the degree to which they pout, and the shape of their inflated crops; in the Carrier, the length, narrowness, and curvature of the beak, and the amount of wattle; in Short-faced Tumblers, the shortness of the beak, the prominence of the forehead, and general carriage,[305] and in the Almond Tumbler the colour of the plumage; in common Tumblers, the manner of tumbling; in the Barb, the breadth and shortness of the beak and the amount of eye-wattle; in Runts, the size of body; in Turbits, the frill; and lastly in Trumpeters, the cooing, as well as the size of the tuft of feathers over the nostrils. These, which are the distinctive and selected characters of the several breeds, are all eminently variable.

There is another interesting fact with respect to the character of the different breeds, namely, that they are often most strongly displayed in the male bird. In Carriers, when the males and females are exhibited in separate pens, the wattle is plainly seen to be much more developed in the males, though I have seen a hen Carrier belonging to Mr. Haynes heavily wattled. Mr. Tegetmeier informs me that, in twenty Barbs in Mr. P. H. Jones's possession, the males had generally the largest eye-wattles; Mr. Esquilant also believes in this rule, but Mr. H. Weir, a first-rate judge, entertains some doubt on the subject. Hale Pouters distend their crops to a much greater size than do the females; I have, however, seen a hen in the possession of Mr. Evans which pouted excellently; but this is an unusual circumstance. Mr. Harrison Weir, a successful breeder of prize {162} Fantails, informs me that his cock birds often have a greater number of tail-feathers than the hens. Mr. Eaton asserts[306] that, if a cock and hen Tumbler were of equal merit, the hen would be worth double the money; and as pigeons always pair, so that an equal number of both sexes is necessary for reproduction, this seems to show that high merit is rarer in the female than in the male. In the development of the frill in Turbits, of the hood in Jacobins, of the tuft in Trumpeters, of tumbling in Tumblers, there is no difference between the males and females. I may here add a rather different case, namely, the existence in France[307] of a wine-coloured variety of the Pouter, in which the male is generally chequered with black, whilst the female is never so chequered. Dr. Chapuis also remarks[308] that in certain light-coloured pigeons the males have their feathers striated with black, and these striae increase in size at each moult, so that the male ultimately becomes spotted with black. With Carriers, the wattle, both on the beak and round the eyes, and with Barbs that round the eyes, goes on increasing with age. This augmentation of character with advancing age, and more especially the difference between the males and females in the above-mentioned several respects, are highly remarkable facts, for there is no sensible difference at any age between the two sexes in the aboriginal rock-pigeon; and rarely any such difference throughout the whole family of the Columbidae.[309]

_Osteological Characters._

In the skeletons of the various breeds there is much variability; and though certain differences occur frequently, and others rarely, in certain breeds, yet none can be said to be absolutely characteristic of any breed. Considering that strongly-marked domestic races have been formed chiefly by man's power {163} of selection, we ought not to expect to find great and constant differences in the skeleton; for fanciers can neither see, nor do they care for, modifications of structure in the internal framework. Nor ought we to expect changes in the skeletons from hanged habits of life; as every facility is given to the most distinct breeds to follow the same habits, and the much modified races are never allowed to wander abroad and procure their own food in various ways. Moreover, I find, on comparing the skeletons of _Columba livia_, _oenas_, _palumbus_, and _turtur_, which are ranked by all systematists in two or three distinct though allied genera, that the differences are extremely slight, certainly less than between the skeletons of some of the most distinct domestic breeds. How far the skeleton of the wild rock-pigeon is constant I have no means of judging, as I have examined only two.

_Skull._--The individual bones, especially those at the base, do not
differ in shape. But the whole skull, in its proportions, outline, and
relative direction of the bones, differs greatly in some of the breeds,
as may be seen by comparing the figures of (A) the wild rock-pigeon,
(B) the {164} shortfaced tumbler, (C) the English carrier, and (D) the
Bagadotten carrier (of Neumeister), all drawn of the natural size and
viewed laterally. In the carrier, besides the elongation of the bones
of the face, the space between the orbits is proportionally a little
narrower than in the rock-pigeon. In the Bagadotten the upper mandible
is remarkably arched, and the premaxillary bones are proportionally
broader. In the short-faced tumbler the skull is more globular; all the
bones of the face are much shortened, and the front of the skull and
descending nasal bones are almost perpendicular; the maxillo-jugal arch
and premaxillary bones form an almost straight line; the space between
the prominent edges of the eye-orbits is depressed. In the barb the
premaxillary bones are much shortened, and their anterior portion is
thicker than in the rock-pigeon, as is the lower part of the nasal
bone. In two nuns the ascending branches of the premaxillaries, near
their tips, were somewhat attenuated, and in these birds, as well as in
some others, for instance in the spot, the occipital crest over the
foramen was considerably more prominent than in the rock-pigeon.

In the lower jaw, the articular surface is proportionally smaller in
many breeds than in the rock-pigeon; and the vertical diameter more
especially of the outer part of the articular surface is considerably
shorter. May not this be accounted for by the lessened use of the jaws,
owing to nutritious food having been given during a long period to all
highly improved pigeons? In runts, carriers, and barbs (and in a lesser
degree in several breeds), the whole side of the jaw near the articular
end is bent inwards in a highly remarkable manner; and the superior
margin of the ramus, beyond the middle, is reflexed in an equally
remarkable manner, as may be seen in the accompanying figures, in
comparison with the jaw of the rock-pigeon. This reflexion of the upper
margin of the lower jaw is plainly connected with the singularly wide
gape of the mouth, as has been described in runts, carriers, and barbs.
The reflexion is well shown in fig. 26 of the head of a runt seen from
above; here a wide open space may be observed on each side, between the
edges of the lower jaw and of the premaxillary {165} bones. In the
rock-pigeon, and in several domestic breeds, the edges of the lower jaw
on each side come close up to the premaxillary bones, so that no open
space is left. The degree of downward curvature of the distal half of
the lower jaw also differs to an extraordinary degree in some breeds,
as may be seen in the drawings (fig. A) of the rock-pigeon, (B) of the
short-faced tumbler, and (C) of the Bagadotten carrier of Neumeister.
In some runts the symphysis of the lower jaw is remarkably solid. No
one would readily have believed that jaws differing so greatly in the
several above-specified points could have belonged to the same species.

_Vertebrae._-- All the breeds have twelve cervical vertebrae.[310] But in
a Bussorah carrier from India, the twelfth vertebra carried a small
rib, a quarter of an inch in length, with a perfect double
articulation.

The _dorsal vertebrae_ are always eight. In the rock-pigeon all eight
bear ribs; the eighth rib being very thin, and the seventh having no
process. In pouters all the ribs are extremely broad, and, in three out
of four skeletons examined by me, the eighth rib was twice or even
thrice as broad as in the rock-pigeon; and the seventh pair had
distinct processes. In many breeds there are only seven ribs, as in
seven out of eight skeletons of various tumblers, and in several
skeletons of fantails, turbits, and nuns. In all these breeds the
seventh pair was very small, and was destitute of processes, in which
respect it differed from the same rib in the rock-pigeon. In one
tumbler, and in the Bussorah carrier, even the sixth pair had no
process. The hypapophysis of the second dorsal vertebra varies much in
development; being sometimes (as in several, but {166} not all
tumblers) nearly as prominent as that of the third dorsal vertebra; and
the two hypapophyses together tend to form an ossified arch. The
development of the arch, formed by the hypapophyses of the third and
fourth dorsal vertebrae, also varies considerably, as does the size of
the hypapophysis of the fifth vertebra.

The rock-pigeon has twelve _sacral vertebrae_; but these vary in number,
relative size, and distinctness in the different breeds. In pouters,
with their elongated bodies, there are thirteen or even fourteen, and,
as we shall immediately see, an additional number of caudal vertebrae.
In runts and carriers there is generally the proper number, namely
twelve; but in one runt, and in the Bussorah carrier, there were only
eleven. In tumblers there are either eleven, twelve, or thirteen sacral
vertebrae.

The _caudal vertebrae_ are seven in number in the rock-pigeon. In
fantails, which have their tails so largely developed, there are either
eight or nine, and apparently in one case ten, and they are a little
longer than in the rock-pigeon, and their shape varies considerably.
Pouters, also, have eight or nine caudal vertebrae. I have seen eight in
a nun and jacobin. Tumblers, though such small birds, always have the
normal number seven; as have carriers, with one exception, in which
there were only six.

The following table will serve as a summary, and will show the most
remarkable deviations in the number of the vertebrae and ribs which I
have observed:--

+----------+-------------+--------------+-----------------+-------------+
| | Rock |Pouter, | Tumbler, | Bussorah |
| | Pigeon. |from Mr. Bult.| Dutch Roller. | Carrier. |
+----------+-------------+--------------+-----------------+-------------+
|Cervical | | | | |
|Vertebrae | 12 | 12 | 12 | 12 |
| | | | | The 12th |
| | | | | bore a |
| | | | | small rib. |
|Dorsal | | | | |
|Vertebrae | 8 | 8 | 8 | 8 |
| | | | | |
|Dorsal | | | | |
|Ribs | 8 | 8 | 7 | 7 |
| |The 6th pair |The 6th & 7th | The 6th & 7th |The 6th & 7th|
| | with | pair with | pair without |pair without |
| | processes, | processes. | processes. | processes. |
| |the 7th pair | | | |
| | without a | | | |
| | process. | | | |
| | | | | |
|Sacral | | | | |
|Vertebrae | 12 | 14 | 11 | 11 |
|Caudal | | | | |
|Vertebrae | 7 | 8 or 9 | 7 | 7 |
| +-------------+--------------+-----------------+-------------+
|Total | | | | |
|Vertebrae | 39 | 42 or 43 | 38 | 38 |
+----------+-------------+--------------+-----------------+-------------+

The _pelvis_ differs very little in any breed. The anterior margin of
the ilium, however, is sometimes a little more equally rounded on both
sides than in the rock-pigeon, The ischium is also frequently rather
more elongated. The obturator-notch is sometimes, as in many tumblers,
less developed than in the rock-pigeon. The ridges on the ilium are
very prominent in most runts.

In the bones of the extremities I could detect no difference, except in
their proportional lengths; for instance, the metatarsus in a pouter
was 1.65 inch, and in a short-faced tumbler only .95 in length; and
this is a greater difference than would naturally follow from their
differently-sized bodies; but long legs in the pouter, and small feet
in the tumbler, are selected points. In some pouters the _scapula_ is
rather straighter, and in some {167} tumblers it is straighter, with
the apex less elongated, than in the rock-pigeon: in the woodcut, fig.
28, the scapulae of the rock-pigeon (A), and of a short-faced tumbler
(B), are given. The processes at the summit of the _coracoid_, which
receive the extremities of the furcula, form a more perfect cavity in
some tumblers than in the rock-pigeon: in pouters these processes are
larger and differently shaped, and the exterior angle of the extremity
of the coracoid, which is articulated to the sternum, is squarer.

The two arms of the _furcula_ in pouters diverge less, proportionally
to their length, than in the rock-pigeon; and the symphysis is more
solid and pointed. In fantails the degree of divergence of the two arms
varies in a remarkable mariner. In fig. 29, B and C represent the
furculae of two fantails; and it will be seen that the divergence in B
is rather less even than in the furcula of the short-faced, small-sized
tumbler (A); whereas the divergence in C equals that in a rock-pigeon,
or in the pouter (D), though the latter is a much larger bird. The
extremities of the furcula, where articulated to the coracoids, vary
considerably in outline.

In the _sternum_ the differences in form are slight, except in the size
and outline of the perforations, which, both in the larger and lesser
sized breeds, are sometimes small. These perforations, also, are
sometimes either nearly circular, or elongated, as is often the case
with carriers. The posterior perforations occasionally are not
complete, being left open posteriorly. The marginal apophyses forming
the anterior perforations vary greatly in development. The degree of
convexity of the posterior part of the sternum differs much, being
sometimes almost perfectly flat. The manubrium is rather more prominent
in some individuals than in others, and the pore immediately under it
varies greatly in size.

_Correlation of Growth._--By this term I mean that the whole organisation is so connected, that when one part varies, other {168} parts vary; but which of two correlated variations ought to be looked at as the cause and which as the effect, or whether both result from some common cause, we can seldom or never tell. The point of interest for us is that, when fanciers, by the continued selection of slight variations, have largely modified one part, they often unintentionally produce other modifications. For instance, the beak is readily acted on by selection, and, with its increased or diminished length, the tongue increases or diminishes, but not in due proportion; for, in a barb and short-faced tumbler, both of which have very short beaks, the tongue, taking the rock-pigeon as the standard of comparison, was proportionally not shortened enough, whilst in two carriers and in a runt the tongue, proportionally with the beak, was not lengthened enough. Thus, in a first-rate English carrier, in which the beak from the tip to the feathered base was exactly thrice as long as in a first-rate short-faced tumbler, the tongue was only a little more than twice as long. But the tongue varies in length independently of the beak: thus, in a carrier with a beak 1.2 inch in length, the tongue was .67 in length; whilst in a runt which equalled the carrier in length of body and in stretch of wings from tip to tip, the beak was .92 whilst the tongue was .73 of an inch in length, so that the tongue was actually longer than in the carrier with its long beak. The tongue of the runt was also very broad at the root. Of two runts, one had its beak longer by .23 of an inch, whilst its tongue was shorter by .14 than in the other.

With the increased or diminished length of the beak the length of the slit forming the external orifice of the nostrils varies, but not in due proportion, for, taking the rock-pigeon as the standard, the orifice in a short-faced tumbler was not shortened in due proportion with its very short beak. On the other hand (and this could not have been anticipated), the orifice in three English carriers, in the Bagadotten carrier, and in a runt (_pigeon cygne_), was longer by above the tenth of an inch than would follow from the length of the beak proportionally with that of the rock-pigeon. In one carrier the orifice of the nostrils was thrice as long as in the rock-pigeon, though in body and length of beak this bird was not nearly double the size of the {169} rock-pigeon. This greatly increased length of the orifice of the nostrils seems to stand partly in correlation with the enlargement of the wattled skin on the upper mandible and over the nostrils; and this is a character which is selected by fanciers. So again, the broad, naked, and wattled skin round the eyes of carriers and barbs is a selected character; and in obvious correlation with this, the eyelids, measured longitudinally, are proportionally more than double the length of those of the rock-pigeon.

The great difference (see woodcut No. 27) in the curvature of the lower jaw in the rock-pigeon, the tumbler, and Bagadotten carrier, stands in obvious relation to the curvature of the upper jaw, and more especially to the angle formed by the maxillo-jugal arch with the premaxillary bones. But in carriers, runts, and barbs the singular reflexion of the upper margin of the middle part of the lower jaw (see woodcut No. 25) is not strictly correlated with the width or divergence (as may be clearly seen in woodcut No. 26) of the premaxillary bones, but with the breadth of the horny and soft parts of the upper mandible, which are always overlapped by the edges of the lower mandible.

In pouters, the elongation of the body is a selected character, and the ribs, as we have seen, have generally become very broad, with the seventh pair furnished with processes; the sacral and caudal vertebrae have been augmented in number; the sternum has likewise increased in length (but not in the depth of the crest) by .4 of an inch more than would follow from the greater bulk of the body in comparison with that of the rock-pigeon. In fantails, the length and number of the caudal vertebrae have increased. Hence, during the gradual progress of variation and selection, the internal bony frame-work and the external shape of the body have been, to a certain extent, modified in a correlated manner.

Although the wings and tail often vary in length independently of each other, it is scarcely possible to doubt that they generally tend to become elongated or shortened in correlation. This is well seen in jacobins, and still more plainly in runts, some varieties of which have their wings and tail of great length, whilst others have both very short. With jacobins, the remarkable length of the tail and {170} wing-feathers is not a character which is intentionally selected by fanciers; but fanciers have been trying for centuries, at least since the year 1600, to increase the length of the reversed feathers on the neck, so that the hood may more completely enclose the head; and it may be suspected that the increased length of the wing and tail-feathers stands in correlation with the increased length of the neck-feathers. Short-faced tumblers have short wings in nearly due proportion with the reduced size of their bodies; but it is remarkable, seeing that the number of the primary wing-feathers is a constant character in most birds, that these tumblers generally have only nine instead of ten primaries. I have myself observed this in eight birds; and the Original Columbarian Society[311] reduced the standard for bald-head tumblers from ten to nine white flight-feathers, thinking it unfair that a bird which had only nine feathers should be disqualified for a prize because it had not ten _white_ flight-feathers. On the other hand, in carriers and runts, which have large bodies and long wings, eleven primary feathers have occasionally been observed.

Mr. Tegetmeier has informed me of a curious and inexplicable case of correlation, namely, that young pigeons of all breeds, which when mature become white, yellow, silver (_i.e._ extremely pale blue), or dun-coloured, are born almost naked; whereas other coloured pigeons are born well clothed with down. Mr. Esquilant, however, has observed that young dun carriers are not so bare as young dun barbs and tumblers. Mr. Tegetmeier has seen two young birds in the same nest, produced from differently coloured parents, which differed greatly in the degree to which they were at first clothed with down.

I have observed another case of correlation which at first sight appears quite inexplicable, but on which, as we shall see in a future chapter, some light can be thrown by the law of homologous parts varying in the same manner. The case is, that, when the feet are much feathered, the roots of the feathers are connected by a web of skin, and apparently in correlation with this the two outer toes become connected for a considerable space by skin. I have observed this in very many {171} specimens of pouters, trumpeters, swallows, roller-tumblers (likewise observed in this breed by Mr. Brent), and in a lesser degree in other feather-footed pigeons.

The feet of the smaller and larger breeds are of course much smaller or larger than those of the rock-pigeon; but the scutellae or scales covering the toes and tarsi have not only decreased or increased in size, but likewise in number. To give a single instance, I have counted eight scutellae on the hind toe of a runt, and only five on that of a short-faced tumbler. With birds in a state of nature the number of the scutellae on the feet is usually a constant character. The length of the feet and the length of the beak apparently stand in correlation; but as disuse apparently has affected the size of the feet, this case may come under the following discussion.

* * * * *

_On the Effects of Disuse_.--In the following discussion on the relative proportions of the feet, sternum, furcula, scapulae, and wings, I may premise, in order to give some confidence to the reader, that my measurements were all made in the same manner, and that all the measurements of the external parts were made without the least intention of applying them to the following purpose.

I measured most of the birds which came into my possession, from the
feathered _base_ of the beak (the length of beak itself being so
variable) to the end of the tail, and to the oil-gland, but
unfortunately (except in a few cases) not to the root of the tail; I
measured each bird from the extreme tip to tip of wing; and the length
of the terminal folded part of the wing, from the extremity of the
primaries to the joint of the radius. I measured the feet without the
claws, from the end of the middle toe to the end of the hind toe; and
the tarsus together with the middle toe. I have taken in every case the
mean measurement of two wild rock-pigeons from the Shetland Islands, as
the standard of comparison. The following table shows the actual length
of the feet in each bird; and the difference between the length which
the feet ought to have had according to the size of body of each, in
comparison with the size of body and length of feet of the rock-pigeon,
calculated (with a few specified exceptions) by the standard of the
length of the body from the base of the beak to the oil-gland. I have
preferred this standard, owing to the variability of the length of
tail. But I have made similar calculations, taking as the standard the
length from tip to tip of wing, and likewise in most cases from the
base of the beak to the end of the tail; and the result has always been
closely similar. To give an example: the first bird in the table, being
a short-faced tumbler, {172} is much smaller than the rock-pigeon, and
would naturally have shorter feet; but it is found on calculation to
have feet too short by .11 of an inch, in comparison with the feet of
the rock-pigeon, relatively to the size of the body in these two birds,
as measured from the base of beak to the oil-gland. So again, when this
same tumbler and the rock-pigeon were compared by the length of their
wings, or by the extreme length of their bodies, the feet of the
tumbler were likewise found to be too short in very nearly the same
proportion. I am well aware that the measurements pretend to greater
accuracy than is possible, but it was less trouble to write down the
actual measurements given by the compasses in each case than an
approximation.

TABLE I.

_Pigeons with their beaks generally shorter than that of the Rock-pigeon, proportionally with the size of their bodies._

+-----------------------------------------+--------+-------------------+
| | | Difference |
| | | between |
| | | actual and |
| | | calculated |
| | | length of |
| Name of Breed. | Actual | feet, in |
| | length | proportion to |
| | of | length of |
| | Feet | feet and size |
| | | of body in the |
| | | Rock-pigeon |
| | +-------------------+
| Wild rock-pigeon (mean measurement) | 2.02 |Too short|Too long |
| | | by | by |
+-----------------------------------------+--------+---------+---------+
| Short-faced Tumbler, bald-head | 1.57 | 0.11 | .. |
| " " almond | 1.60 | 0.16 | .. |
| Tumbler, red magpie | 1.75 | 0.19 | .. |
| " red common (by standard | | | |
| to end of tail) | 1.85 | 0.07 | .. |
| " common bald-head | 1.85 | 0.18 | .. |
| " roller | 1.80 | 0.06 | .. |
| Turbit | 1.75 | 0.17 | .. |
| " | 1.80 | 0.01 | .. |
| " | 1.84 | 0.15 | .. |
| Jacobin | 1.90 | 0.02 | .. |
| Trumpeter, white | 2.02 | 0.06 | .. |
| " mottled | 1.95 | 0.18 | .. |
| Fantail (by standard to end of tail) | 1.85 | 0.15 | .. |
| " " " | 1.95 | 0.15 | .. |
| " crested var. " | 1.95 | 0.0 | 0.0 |
| Indian Frill-back | 1.80 | 0.19 | .. |
| English Frill-back | 2.10 | 0.03 | .. |
| Nun | 1.82 | 0.02 | .. |
| Laugher | 1.65 | 0.16 | .. |
| Barb | 2.00 | 0.03 | .. |
| " | 2.00 | .. | 0.03 |
| Spot | 1.90 | 0.02 | .. |
| " | 1.90 | 0.07 | .. |
| Swallow, red | 1.85 | 0.18 | .. |
| " blue | 2.00 | .. | 0.03 |
| Pouter | 2.42 | .. | 0.11 |
| " German | 2.30 | .. | 0.09 |
| Bussorah Carrier | 2.17 | .. | 0.09 |
| +--------+---------+---------+
| Number of specimens | 28 | 22 | 5 |
+-----------------------------------------+--------+---------+---------+

{173}

TABLE II.

_Pigeons with their beaks longer than that of the Rock-pigeon, proportionally with the size of their bodies._

+--------------------------------------+----------+---------------------+
| | | Difference |
| | | between |
| | | actual and |
| | | calculated |
| | | length of |
| Name of Breed. | Actual | feet, in |
| | length | proportion to |
| | of | length of |
| | Feet | feet and size |
| | | of body in the |
| | | Rock-pigeon |
| | +----------+----------+
| Wild rock-pigeon (mean measurement) | 2.02 | Too short| Too long |
| | | by | by |
+--------------------------------------+----------+----------+----------+
| Carrier | 2.60 | .. | 0.31 |
| " | 2.60 | .. | 0.25 |
| " | 2.40 | .. | 0.21 |
| " Dragon | 2.25 | .. | 0.06 |
| Bagadotten Carrier | 2.80 | .. | 0.56 |
| Scanderoon, white | 2.80 | .. | 0.37 |
| " Pigeon cygne | 2.85 | .. | 0.29 |
| Runt | 2.75 | .. | 0.27 |
| +----------+----------+----------+
| Number of specimens | 8 | .. | 8 |
+--------------------------------------+----------+----------+----------+

In these two tables we see in the first column the actual length of the
feet in thirty-six birds belonging to various breeds, and in the two
other columns we see by how much the feet are too short or too long,
according to the size of bird, in comparison with the rock-pigeon. In
the first table twenty-two specimens have their feet too short, on an
average by a little above the tenth of an inch (viz. .107); and five
specimens have their feet on an average a very little too long, namely,
by .07 of an inch. But some of these latter and exceptional cases can
be explained; for instance, with pouters the legs and feet are selected
for length, and thus any natural tendency to a diminution in the length
of the feet will have been counteracted. In the swallow and barb, when
the calculation was made on any standard of comparison excepting the
one above used (viz. length of body from base of beak to oil-gland),
the feet were found to be too small.

In the second table we have eight birds, with their beaks much longer
than in the rock-pigeon, both actually and proportionally with the size
of body, and their feet are in an equally marked manner longer, namely,
in proportion, on an average by .29 of an inch. I should here state
that in Table I. there are a few partial exceptions to the beak being
proportionally shorter than in the rock-pigeon: thus the beak of the
English frill-back is just perceptibly longer, and that of the Bussorah
carrier of the same length or slightly longer, than in the rock-pigeon.
The beaks of spots, swallows, and laughers are only a very little
shorter, or of the same proportional length, but slenderer.
Nevertheless, these two tables, taken conjointly, indicate pretty
plainly some kind of correlation between the length of the beak and the
size of the feet. Breeders of cattle and horses believe that there is
an analogous connection between the length of the limbs and head; they
assert that a race-horse with the head of a dray-horse, or a {174}
greyhound with the head of a bulldog, would be a monstrous production.
As fancy pigeons are generally kept in small aviaries, and are
abundantly supplied with food, they must walk about much less than the
wild rock-pigeon; and it may be admitted as highly probable that the
reduction in the size of the feet in the twenty-two birds in the first
table has been caused by disuse,[312] and that this reduction has acted
by correlation on the beaks of the great majority of the birds in Table
I. When, on the other hand, the beak has been much elongated by the
continued selection of successive slight increments of length, the feet
by correlation have likewise become much elongated in comparison with
those of the wild rock-pigeon, notwithstanding their lessened use.

As I had taken measures from the end of the middle toe to the heel of
the tarsus in the rock-pigeon and in the above thirty-six birds, I have
made calculations analogous with those above given, and the result is
the same,--namely, that in the short-beaked breeds, with equally few
exceptions as in the former case, the middle toe conjointly with the
tarsus has decreased in length; whereas in the long-beaked breeds it
has increased in length, though not quite so uniformly as in the former
case, for the leg in some varieties of the runt varies much in length.

As fancy pigeons are generally confined in aviaries of moderate size,
and as even when not confined they do not search for their own food,
they must during many generations have used their wings incomparably
less than the wild rock-pigeon. Hence it seemed to me probable that all
the parts of the skeleton subservient to flight would be found to be
reduced in size. With respect to the sternum, I have carefully measured
its extreme length in twelve birds of different breeds, and in two wild
rock-pigeons from the Shetland Islands. For the proportional comparison
I have tried with all twelve birds three standards of measurement,
namely, the length from the base of the beak to the oil-gland, to the
end of the tail, and from the extreme tip to tip of wings. The result
has been in each case nearly the same, the sternum being invariably
found to be shorter than in the wild rock-pigeon. I will give only a
single table, as calculated by the standard from the base of the beak
to the oil-gland; for the result in this case is nearly the mean
between the results obtained by the two other standards.

_Length of Sternum._

+--------------------+-------+-------+-------------------+-------+------+
| |Actual | Too | |Actual | Too |
| Name of Breed. |Length.| Short | Name of Breed. |Length.| Short|
| |Inches.| by | |Inches.| by |
+--------------------+-------+-------+-------------------+-------+------+
| Wild Rock-pigeon | 2.55 | .. | Barb | 2.35 | 0.34 |
| Pied Scanderoon | 2.80 | 0.60 | Nun | 2.27 | 0.15 |
| Bagadotten Carrier | 2.80 | 0.17 | German Pouter | 2.36 | 0.54 |
| Dragon | 2.45 | 0.41 | Jacobin | 2.33 | 0.22 |
| Carrier | 2.75 | 0.35 | English Frill-back| 2.40 | 0.43 |
| Short-faced Tumbler| 2.05 | 0.28 | Swallow | 2.45 | 0.17 |
+--------------------+-------+-------+-------------------+-------+------+

{175}

This table shows that in these twelve breeds the sternum is on an
average one-third of an inch (exactly .332) shorter than in the
rock-pigeon, proportionally with the size of their bodies; so that the
sternum has been reduced by between one-seventh and one-eighth of its
entire length; and this is a considerable reduction.

I have also measured in twenty-one birds, including the above dozen,
the prominence of the crest of the sternum relatively to its length,
independently of the size of the body. In two of the twenty-one birds
the crest was prominent in the same relative degree as in the
rock-pigeon; in seven it was more prominent; but in five out of these
seven, namely, in a fantail, two scanderoons, and two English carriers,
this greater prominence may to a certain extent be explained, as a
prominent breast is admired and selected by fanciers; in the remaining
twelve birds the prominence was less. Hence it follows that the crest
exhibits a slight, though uncertain, tendency to become reduced in
prominence in a greater degree than does the length of the sternum
relatively to the size of body, in comparison with the rock-pigeon.

I have measured the length of the scapula in nine different large and
small-sized breeds, and in all the scapula is proportionally shorter
(taking the same standard as before) than in the wild rock-pigeon. The
reduction in length on an average is very nearly one-fifth of an inch,
or about one-ninth of the length of the scapula in the rock-pigeon.

The arms of the furcula in all the specimens which I compared, diverged
less, proportionally with the size of body, than in the rock-pigeon;
and the whole furcula was proportionally shorter. Thus in a runt, which
measured from tip to tip of wings 381/2 inches, the furcula was only a
very little longer (with the arms hardly more divergent) than in a
rock-pigeon which measured from tip to tip 261/2 inches. In a barb, which
in all its measurements was a little larger than the same rock-pigeon,
the furcula was a quarter of an inch shorter. In a pouter, the furcula
had not been lengthened proportionally with the increased length of the
body. In a short-faced tumbler, which measured from tip to tip of wings
24 inches, therefore only 21/2 inches less than the rock-pigeon, the
furcula was barely two-thirds of the length of that of the rock-pigeon.

We thus clearly see that the sternum, scapulae, and furcula are all reduced in proportional length; but when we turn to the wings we find what at first appears a wholly different and unexpected result. I may here remark that I have not picked out specimens, but have used every measurement made by me. Taking the length from the base of beak to the end of the tail as the standard of comparison, I find that, out of thirty-five birds of various breeds, twenty-five have wings of greater, and ten have them of less proportional length, than in the rock-pigeon. But from the frequently correlated length of the tail and wing-feathers, it is better to take as the standard {176} of comparison the length from the base of the beak to the oil-gland; and by this standard, out of twenty-six of the same birds which had been thus measured, twenty-one had wings too long, and only five had them too short. In the twenty-one birds the wings exceeded in length those of the rock-pigeon, on an average, by 1-1/3 inch; whilst in the five birds they were less in length by only .8 of an inch. As I was much surprised that the wings of closely confined birds should thus so frequently have been increased in length, it occurred to me that it might be solely due to the greater length of the wing-feathers; for this certainly is the case with the jacobin, which has wings of unusual length. As in almost every case I had measured the folded wings, I subtracted the length of this terminal part from that of the expanded wings, and thus I obtained, with a moderate degree of accuracy, the length of the wings from the ends of the two radii, answering from wrist to wrist in our arms. The wings, thus measured in the same twenty-five birds, now gave a widely different result; for they were proportionally with those of the rock-pigeon too short in seventeen birds, and in only eight too long. Of these eight birds, five were long-beaked,[313] and this fact perhaps indicates that there is some correlation between the length of the beak and the length of the bones of the wings, in the same manner as with the feet and tarsi. The shortening of the humerus and radius in the seventeen birds may probably be attributed to disuse, as in the case of the scapulae and furcula to which the wing-bones are attached;--the lengthening of the wing-feathers, and consequently the expansion of the wings from tip to tip, being, on the other hand, as completely independent of use and disuse as is the growth of the hair or wool on our long-haired dogs or long-woolled sheep.