Chapter VI: PIGEONS—continued (1)

ON THE ABORIGINAL PARENT-STOCK OF THE SEVERAL DOMESTIC RACES—HABITS OF LIFE—WILD RACES OF THE ROCK-PIGEON—Dovecot-PIGEONS—PROOFS OF THE DESCENT OF THE SEVERAL RACES FROM COLUMBA LIVIA—FERTILITY OF THE RACES WHEN CROSSED—REVERSION TO THE PLUMAGE OF THE WILD ROCK-PIGEON—CIRCUMSTANCES FAVOURABLE TO THE FORMATION OF THE RACES—ANTIQUITY AND HISTORY OF THE PRINCIPAL RACES—MANNER OF THEIR FORMATION—SELECTION—UNCONSCIOUS SELECTION—CARE TAKEN BY FANCIERS IN SELECTING THEIR BIRDS—SLIGHTLY DIFFERENT STRAINS GRADUALLY CHANGE INTO WELL-MARKED BREEDS—EXTINCTION OF INTERMEDIATE FORMS—CERTAIN BREEDS REMAIN PERMANENT, WHILST OTHERS CHANGE—SUMMARY.

The differences described in the last chapter between the eleven chief domestic races and between individual birds of the same race, would be of little significance, if they had not all descended from a single wild stock. The question of their origin is therefore of fundamental importance, and must be discussed at considerable length. No one will think this superfluous who considers the great amount of difference between the races, who knows how ancient many of them are, and how truly they breed at the present day. Fanciers almost unanimously believe that the different races are descended from several wild stocks, whereas most naturalists believe that all are descended from the Columba livia or rock-pigeon.

Temminck[1] has well observed, and Mr. Gould has made the same
remark to me, that the aboriginal parent must have been a species
which roosted and built its nest on rocks; and I may add that it
must have been a social bird. For all the domestic races are highly
social, and none are known to build or habitually to roost on
trees. The awkward manner in which some pigeons, kept by me in a
summer-house near an old walnut-tree, occasionally alighted on the
barer branches, was evident.[2] Nevertheless, Mr. R. Scot Skirving
informs me that he often saw crowds of pigeons in Upper Egypt
settling on low trees, but not on palms, in preference to alighting
on the mud hovels of the natives. In India Mr. Blyth[3] has been
assured that the wild _C. livia,_ var. _intermedia,_ sometimes
roosts in trees. I may here give a curious instance of compulsion
leading to changed habits: the banks of the Nile above lat. 28° 30′
are perpendicular for a long distance, so that when the river is
full the pigeons cannot alight on the shore to drink, and Mr.
Skirving repeatedly saw whole flocks settle on the water, and drink
whilst they floated down the stream. These flocks seen from a
distance resembled flocks of gulls on the surface of the sea.

If any domestic race had descended from a species which was not
social, or which built its nest and roosted in trees,[4] the sharp
eyes of fanciers would assuredly have detected some vestige of so
different an aboriginal habit. For we have reason to believe that
aboriginal habits are long retained under domestication. Thus with
the common ass we see signs of its original desert life in its
strong dislike to cross the smallest stream of water, and in its
pleasure in rolling in the dust. The same strong dislike to cross a
stream is common to the camel, which has been domesticated from a
very ancient period. Young pigs, though so tame, sometimes squat
when frightened, and thus try to conceal themselves even on an open
and bare place. Young turkeys, and occasionally even young fowls,
when the hen gives the danger-cry, run away and try to hide
themselves, like young partridges or pheasants, in order that their
mother may take flight, of which she has lost the power. The
musk-duck (_Cairina moschata_) in its native country often perches
and roosts on trees,[5] and our domesticated musk-ducks, though
such sluggish birds, “are fond of perching on the tops of barns,
walls, etc., and, if allowed to spend the night in the hen-house,
the female will generally go to roost by the side of the hens, but
the drake is too heavy to mount thither with ease.”[6] We know that
the dog, however well and regularly fed, often buries, like the
fox, any superfluous food; and we see him turning round and round
on a carpet, as if to trample down grass to form a bed; we see him
on bare pavements scratching backwards as if to throw earth over
his excrement, although, as I believe, this is never effected even
where there is earth. In the delight with which lambs and kids
crowd together and frisk on the smallest hillock, we see a vestige
of their former alpine habits.

We have therefore good reason to believe that all the domestic races of the pigeon are descended either from some one or from several species which both roosted and built their nests on rocks, and were social in disposition. As only five or six wild species have these habits, and make any near approach in structure to the domesticated pigeon, I will enumerate them.

Firstly, the _Columba leuconota_ resembles certain domestic
varieties in its plumage, with the one marked and never-failing
difference of a white band which crosses the tail at some distance
from the extremity. This species, moreover, inhabits the Himalaya,
close to the limit of perpetual snow; and therefore, as Mr. Blyth
has remarked, is not likely to have been the parent of our domestic
breeds, which thrive in the hottest countries. Secondly, the _C.
rupestris,_ of Central Asia, which is intermediate[7] between the
_C. leuconota_ and _livia_; but has nearly the same coloured tail
as the former species. Thirdly, the _ Columba littoralis_ builds
and roosts, according to Temminck, on rocks in the Malayan
archipelago; it is white, excepting parts of the wing and the tip
of the tail, which are black; its legs are livid-coloured, and this
is a character not observed in any adult domestic pigeon; but I
need not have mentioned this species or the closely-allied _C.
luctuosa,_ as they in fact belong to the genus Carpophaga.
Fourthly, _Columba guinea,_ which ranges from Guinea[8] to the Cape
of Good Hope, and roosts either on trees or rocks, according to the
nature of the country. This species belongs to the genus
Strictoenas of Reichenbach, but is closely allied to Columba; it is
to some extent coloured like certain domestic races, and has been
said to be domesticated in Abyssinia; but Mr. Mansfield Parkyns,
who collected the birds of that country and knows the species,
informs me that this is a mistake. Moreover, the _C. guinea_ is
characterised by the feathers of the neck having peculiar notched
tips,—a character not observed in any domestic race. Fifthly, the _
Columba œnas_ of Europe, which roosts on trees, and builds its nest
in holes, either in trees or the ground; this species, as far as
external characters go, might be the parent of several domestic
races; but, though it crosses readily with the true rock-pigeon,
the offspring, as we shall presently see, are sterile hybrids, and
of such sterility there is not a trace when the domestic races are
intercrossed. It should also be observed that if we were to admit,
against all probability, that any of the foregoing five or six
species were the parents of some of our domestic pigeons, not the
least light would be thrown on the chief differences between the
eleven most strongly-marked races.

We now come to the best known rock-pigeon, the _Columba livia,_
which is often designated in Europe pre-eminently as the
Rock-pigeon, and which naturalists believe to be the parent of all
the domesticated breeds. This bird agrees in every essential
character with the breeds which have been only slightly modified.
It differs from all other species in being of a slaty-blue colour,
with two black bars on the wings, and with the croup (or loins)
white. Occasionally birds are seen in Faroe and the Hebrides with
the black bars replaced by two or three black spots; this form has
been named by Brehm[9] _C. amaliæ,_ but this species has not been
admitted as distinct by other ornithologists. Graba[10] even found
a difference in the bars on the right and left wings of the same
bird in Faroe. Another and rather more distinct form is either
truly wild or has become feral on the cliffs of England and was
doubtfully named by Mr. Blyth[11] as _C. affinis,_ but is now no
longer considered by him as a distinct species. _C. affinis_ is
rather smaller than the rock-pigeon of the Scottish islands, and
has a very different appearance owing to the wing-coverts being
chequered with black, with similar marks often extending over the
back. The chequering consists of a large black spot on the two
sides, but chiefly on the outer side, of each feather. The
wing-bars in the true rock-pigeon and in the chequered variety are,
in fact, due to similar though larger spots symmetrically crossing
the secondary wing-feather and the larger coverts. Hence the
chequering arises merely from an extension of these marks to other
parts of the plumage. Chequered birds are not confined to the
coasts of England; for they were found by Graba at Faroe; and W.
Thompson[12] says that at Islay fully half the wild rock-pigeons
were chequered. Colonel King, of Hythe, stocked his dovecot with
young wild birds which he himself procured from nests at the Orkney
Islands; and several specimens, kindly sent to me by him, were all
plainly chequered. As we thus see that chequered birds occur
mingled with the true rock-pigeon at three distinct sites, namely,
Faroe, the Orkney Islands, and Islay, no importance can be attached
to this natural variation in the plumage.

Prince C. L. Bonaparte,[13] a great divider of species, enumerates,
with a mark of interrogation, as distinct from _C. livia,_ the _C.
turricola_ of Italy, the _C. rupestris_ of Daouria, and the _C.
schimperi_ of Abyssinia; but these birds differ from _C. livia_ in
characters of the most trifling value. In the British Museum there
is a chequered pigeon, probably the _C. schimperi_ of Bonaparte,
from Abyssinia. To these may be added the _C. gymnocyclus_ of G. R.
Gray from W. Africa, which is slightly more distinct, and has
rather more naked skin round the eyes than the rock-pigeon; but
from information given me by Dr. Daniell, it is doubtful whether
this is a wild bird, for dovecot-pigeons (which I have examined)
are kept on the coast of Guinea.

The wild rock-pigeon of India (_C. intermedia_ of Strickland) has
been more generally accepted as a distinct species. It differs
chiefly in the croup being blue instead of snow-white; but as Mr.
Blyth informs me, the tint varies, being sometimes albescent. When
this form is domesticated chequered birds appear, just as occurs in
Europe with the truly wild _C. livia._ Moreover we shall
immediately have proof that the blue and white croup is a highly
variable character; and Bechstein[14] asserts that with
dovecot-pigeons in Germany this is the most variable of all the
characters of the plumage. Hence it may be concluded that _C.
intermedia_ cannot be ranked as specifically distinct from _C.
livia._

In Madeira there is a rock-pigeon which a few ornithologists have suspected to be distinct from _C. livia._ I have examined numerous specimens collected by Mr. E. V. Harcourt and Mr. Mason. They are rather smaller than the rock- pigeon from the Shetland Islands, and their beaks are plainly thinner, but the thickness of the beak varied in the several specimens. In plumage there is remarkable diversity; some specimens are identical in every feather (I speak after actual comparison) with the rock-pigeon of the Shetland Islands; others are chequered, like _C. affinis_ from the cliffs of England, but generally to a greater degree, being almost black over the whole back; others are identical with the so-called _C. intermedia_ of India in the degree of blueness of the croup; whilst others have this part very pale or very dark blue, and are likewise chequered. So much variability raises a strong suspicion that these birds are domestic pigeons which have become feral.

From these facts it can hardly be doubted that _C. livia, affinis,
intermedia,_ and the forms marked with an interrogation by
Bonaparte ought all to be included under a single species. But it
is quite immaterial whether or not they are thus ranked, and
whether some one of these forms or all are the progenitors of the
various domestic kinds, as far as any light can thus be thrown on
the differences between the more strongly-marked races. That common
dovecot-pigeons, which are kept in various parts of the world, are
descended from one or from several of the above-mentioned wild
varieties of _C. livia,_ no one who compares them will doubt. But
before making a few remarks on dovecot-pigeons, it should be stated
that the wild rock-pigeon has been found easy to tame in several
countries. We have seen that Colonel King at Hythe stocked his
dovecot more than twenty years ago with young wild birds taken at
the Orkney Islands, and since then they have greatly multiplied.
The accurate Macgillivray[15] asserts that he completely tamed a
wild rock-pigeon in the Hebrides; and several accounts are on
records of these pigeons having bred in dovecots in the Shetland
Islands. In India, as Captain Hutton informs me, the wild
rock-pigeon is easily tamed, and breeds readily with the domestic
kind; and Mr. Blyth[16] asserts that wild birds come frequently to
the dovecots and mingle freely with their inhabitants. In the
ancient ‘Ayeen Akbery’ it is written that, if a few wild pigeons be
taken, “they are speedily joined by a thousand others of their
kind.”

Dovecot-pigeons are those which are kept in dovecots in a semi-
domesticated state; for no special care is taken of them, and they
procure their own food, except during the severest weather. In
England, and, judging from MM. Boitard and Corbié’s work, in
France, the common dovecot- pigeon exactly resembles the chequered
variety of _C. livia;_ but I have seen dovecots brought from
Yorkshire without any trace of chequering, like the wild
rock-pigeon of the Shetland Islands. The chequered dovecots from
the Orkney Islands, after having been domesticated by Colonel King
for more than twenty years, differed slightly from each other in
the darkness of their plumage and in the thickness of their beaks;
the thinnest beak being rather thicker than the thickest one in the
Madeira birds. In Germany, according to Bechstein, the common
dovecot-pigeon is not chequered. In India they often become
chequered, and sometimes pied with white; the croup also, as I am
informed by Mr. Blyth, becomes nearly white. I have received from
Sir. J. Brooke some dovecot-pigeons, which originally came from the
S. Natunas Islands in the Malay Archipelago, and which had been
crossed with the Singapore dovecots: they were small and the
darkest variety was extremely like the dark chequered variety with
a blue croup from Madeira; but the beak was not so thin, though
decidedly thinner than in the rock- pigeon from the Shetland
Islands. A dovecot-pigeon sent to me by Mr. Swinhoe from Foochow,
in China, was likewise rather small, but differed in no other
respect. I have also received through the kindness of Dr. Daniell,
four living dovecot-pigeons from Sierra Leone,[17] these were fully
as large as the Shetland rock-pigeon, with even bulkier bodies. In
plumage some of them were identical with the Shetland rock pigeon,
but with the metallic tints apparently rather more brilliant;
others had a blue croup, and resembled the chequered variety of _C.
intermedia_ of India; and some were so much chequered as to be
nearly black. In these four birds the beak differed slightly in
length, but in all it was decidedly shorter, more massive, and
stronger than in the wild rock-pigeon from the Shetland Islands, or
in the English dovecot. When the beaks of these African pigeons
were compared with the thinnest beaks of the wild Madeira
specimens, the contrast was great; the former being fully one-third
thicker in a vertical direction than the latter; so that any one at
first would have felt inclined to rank these birds as specifically
distinct; yet so perfectly graduated a series could be formed
between the above-mentioned varieties, that it was obviously
impossible to separate them.

To sum up: the wild _Columba livia,_ including under this name _C. affinis, intermedia,_ and the other still more closely-affined geographical races, has a vast range from the southern coast of Norway and the Faroe Islands to the shores of the Mediterranean, to Madeira and the Canary Islands, to Abyssinia, India, and Japan. It varies greatly in plumage, being in many places chequered with black, and having either a white or blue croup or loins; it varies also slightly in the size of the beak and body. Dovecot-pigeons, which no one disputes are descended from one or more of the above wild forms, present a similar but greater range of variation in plumage, in the size of body, and in the length and thickness of the beak. There seems to be some relation between the croup being blue or white, and the temperature of the country inhabited by both wild and dovecot pigeons; for nearly all the dovecot-pigeons in the northern parts of Europe have a white croup, like that of the wild European rock-pigeon; and nearly all the dovecot-pigeons of India have a blue croup like that of the wild _C. intermedia_ of India. As in various countries the wild rock-pigeon has been found easy to tame, it seems extremely probable that the dovecot-pigeons throughout the world are the descendants of at least two and perhaps more wild stocks; but these, as we have just seen, cannot be ranked as specifically distinct.

With respect to the variation of _C. livia,_ we may without fear of contradiction go one step further. Those pigeon-fanciers who believe that all the chief races, such as Carriers, Pouters, Fantails, etc., are descended from distinct aboriginal stocks, yet admit that the so-called toy-pigeons, which differ from the rock-pigeon in little except colour, are descended from this bird. By toy-pigeons are meant such birds as Spots, Nuns, Helmets, Swallows, Priests, Monks, Porcelains, Swabians, Archangels, Breasts, Shields, and others in Europe, and many others in India. It would indeed be as puerile to suppose that all these birds are descended from so many distinct wild stocks as to suppose this to be the case with the many varieties of the gooseberry, heartsease, or dahlia. Yet these kinds all breed true, and many of them include sub-varieties which likewise transmit their character truly. They differ greatly from each other and from the rock-pigeon in plumage, slightly in size and proportions of body, in size of feet, and in the length and thickness of their beaks. They differ from each other in these respects more than do dovecot-pigeons. Although we may safely admit that dovecot-pigeons, which vary slightly, and that toy- pigeons, which vary in a greater degree in accordance with their more highly-domesticated condition, are descended from _C. livia,_ including under this name the above-enumerated wild geographical races; yet the question becomes far more difficult when we consider the eleven principal races, most of which have been profoundly modified. It can, however, be shown, by indirect evidence of a perfectly conclusive nature, that these principal races are not descended from so many wild stocks; and if this be once admitted, few will dispute that they are the descendants of _C. livia,_ which agrees with them so closely in habits and in most characters, which varies in a state of nature, and which has certainly undergone a considerable amount of variation, as in the toy-pigeons. We shall moreover presently see how eminently favourable circumstances have been for a great amount of modification in the more carefully tended breeds.

The reasons for concluding that the several principal races are not descended from so many aboriginal and unknown stocks may be grouped under the following six heads:—

_Firstly._—If the eleven chief races have not arisen from the variation of some one species, together with its geographical races, they must be descended from several extremely distinct aboriginal species; for no amount of crossing between only six or seven wild forms could produce races so distinct as Pouters, Carriers, Runts, Fantails, Turbits, Short-faced Tumblers, Jacobins, and Trumpeters. How could crossing produce, for instance, a Pouter or a Fantail, unless the two supposed aboriginal parents possessed the remarkable characters of these breeds? I am aware that some naturalists, following Pallas, believe that crossing gives a strong tendency to variation, independently of the characters inherited from either parent. They believe that it would be easier to raise a Pouter or Fantail pigeon from crossing two distinct species, neither of which possessed the characters of these races, than from any single species. I can find few facts in support of this doctrine, and believe in it only to a limited degree; but in a future chapter I shall have to recur to this subject. For our present purpose the point is not material. The question which concerns us is, whether or not many new and important characters have arisen since man first domesticated the pigeon. On the ordinary view, variability is due to changed conditions of life; on the Pallasian doctrine, variability, or the appearance of new characters, is due to some mysterious effect from the crossing of two species, neither of which possesses the characters in question. In some few instances it is possible that well-marked races may have been formed by crossing; for instance, a Barb might perhaps be formed by a cross between a long-beaked Carrier, having large eye-wattles, and some short-beaked pigeon. That many races have been in some degree modified by crossing, and that certain varieties which are distinguished only by peculiar tints have arisen from crosses between differently-coloured varieties, is almost certain. On the doctrine, therefore, that the chief races owe their differences to their descent from distinct species, we must admit that at least eight or nine, or more probably a dozen species, all having the same habit of breeding and roosting on rocks and living in society, either now exist somewhere, or formerly existed, but have become extinct as wild birds. Considering how carefully wild pigeons have been collected throughout the world, and what conspicuous birds they are, especially when frequenting rocks, it is extremely improbable that eight or nine species, which were long ago domesticated and therefore must have inhabited some anciently known country, should still exist in the wild state and be unknown to ornithologists.

The hypothesis that such species formerly existed, but have become extinct, is in some slight degree more probable. But the extinction of so many species within the historical period is a bold hypothesis, seeing how little influence man has had in exterminating the common rock-pigeon, which agrees in all its habits of life with the domestic races. The _C. livia_ now exists and flourishes on the small northern islands of Faroe, on many islands off the coast of Scotland, on Sardinia, and the shores of the Mediterranean, and in the centre of India. Fanciers have sometimes imagined that the several supposed parent-species were originally confined to small islands, and thus might readily have been exterminated; but the facts just given do not favour the probability of their extinction, even on small islands. Nor is it probable, from what is known of the distribution of birds, that the islands near Europe should have been inhabited by peculiar species of pigeons; and if we assume that distant oceanic islands were the homes of the supposed parent-species, we must remember that ancient voyages were tediously slow, and that ships were then ill-provided with fresh food, so that it would not have been easy to bring home living birds. I have said ancient voyages, for nearly all the races of the pigeon were known before the year 1600, so that the supposed wild species must have been captured and domesticated before that date.

_Secondly._—The doctrine that the chief domestic races are descended from several aboriginal species, implies that several species were formerly so thoroughly domesticated as to breed readily when confined. Although it is easy to tame most wild birds, experience shows us that it is difficult to get them to breed freely under confinement; although it must be owned that this is less difficult with pigeons than with most other birds. During the last two or three hundred years, many birds have been kept in aviaries, but hardly one has been added to our list of thoroughly reclaimed species: yet on the above doctrine we must admit that in ancient times nearly a dozen kinds of pigeons, now unknown in the wild state, were thoroughly domesticated.

_Thirdly._—Most of our domesticated animals have run wild in
various parts of the world; but birds, owing apparently to their
partial loss of the power of flight, less often than quadrupeds.
Nevertheless I have met with accounts showing that the common fowl
has become feral in South America and perhaps in West Africa, and
on several islands: the turkey was at one time almost feral on the
banks of the Parana; and the Guinea-fowl has become perfectly wild
at Ascension and in Jamaica. In this latter island the peacock,
also, “has become a maroon bird.” The common duck wanders from its
home and becomes almost wild in Norfolk. Hybrids between the common
and musk-duck which have become wild have been shot in North
America, Belgium, and near the Caspian Sea. The goose is said to
have run wild in La Plata. The common dovecot-pigeon has become
wild at Juan Fernandez, Norfolk Island, Ascension, probably at
Madeira, on the shores of Scotland, and, as is asserted, on the
banks of the Hudson in North America.[18] But how different is the
case, when we turn to the eleven chief domestic races of the
pigeon, which are supposed by some authors to be descended from so
many distinct species! no one has ever pretended that any one of
these races has been found wild in any quarter of the world; yet
they have been transported to all countries, and some of them must
have been carried back to their native homes. On the view that all
the races are the product of variation, we can understand why they
have not become feral, for the great amount of modification which
they have undergone shows how long and how thoroughly they have
been domesticated; and this would unfit them for a wild life.

_Fourthly._—If it be assumed that the characteristic differences between the various domestic races are due to descent from several aboriginal species, we must conclude that man chose for domestication in ancient times, either intentionally or by chance, a most abnormal set of pigeons; for that species resembling such birds as Pouters, Fantails, Carriers, Barbs, Short-faced Tumblers, Turbits, etc., would be in the highest degree abnormal, as compared with all the existing members of the great pigeon family, cannot be doubted. Thus we should have to believe that man not only formerly succeeded in thoroughly domesticating several highly abnormal species, but that these same species have since all become extinct, or are at least now unknown. This double accident is so extremely improbable that the assumed existence of so many abnormal species would require to be supported by the strongest evidence. On the other hand, if all the races are descended from _C. livia,_ we can understand, as will hereafter be more fully explained, how any slight deviation in structure which first appeared would continually be augmented by the preservation of the most strongly marked individuals; and as the power of selection would be applied according to man’s fancy, and not for the bird’s own good, the accumulated amount of deviation would certainly be of an abnormal nature in comparison with the structure of pigeons living in a state of nature.

I have already alluded to the remarkable fact that the characteristic differences between the chief domestic races are eminently variable; we see this plainly in the great difference in the number of the tail-feathers in the Fantail, in the development of the crop in Pouters, in the length of the beak in Tumblers, in the state of the wattle in Carriers, etc. If these characters are the result of successive variations added together by selection, we can understand why they should be so variable: for these are the very parts which have varied since the domestication of the pigeon, and therefore would be likely still to vary; these variations moreover have been recently, and are still being accumulated by man’s selection; therefore they have not as yet become firmly fixed.

_Fifthly._—All the domestic races pair readily together, and, what
is equally important, their mongrel offspring are perfectly
fertile. To ascertain this fact I made many experiments, which are
given in the note below; and recently Mr. Tegetmeier has made
similar experiments with the same result.[19] The accurate
Neumeister asserts that when dovecots are crossed with pigeons of
any other breed, the mongrels are extremely fertile and hardy.[20]
MM. Boitard and Corbié[21] affirm, after their great experience,
that the more distinct the breeds are which are crossed, the more
productive are their mongrel offspring. I admit that the doctrine
first broached by Pallas is highly probable, if not actually
proved, namely, that closely allied species, which in a state of
nature or when first captured would have been in some degree
sterile if crossed, lose this sterility after a long course of
domestication; yet when we consider the great difference between
such races as Pouters, Carriers, Runts, Fantails, Turbits, Tumblers
etc., the fact of their perfect, or even increased, fertility when
intercrossed in the most complicated manner becomes a strong
argument in favour of their having all descended from a single
species. This argument is rendered much stronger when we hear (I
append in a note[22] all the cases which I have collected) that
hardly a single well-ascertained instance is known of hybrids
between two true species of pigeons being fertile, _inter se,_ or
even when crossed with one of their pure parents.

_Sixthly._—Excluding certain important characteristic differences, the chief races agree most closely both with each other and with _C. livia_ in all other respects. As previously observed, all are eminently sociable; all dislike to perch or roost, and refuse to build in trees; all lay two eggs, and this is not a universal rule with the Columbidæ; all, as far as I can hear, require the same time for hatching their eggs; all can endure the same great range of climate; all prefer the same food, and are passionately fond of salt; all exhibit (with the asserted exception of the Finnikin and Turner which do not differ much in any other character) the same peculiar gestures when courting the females; and all (with the exception of Trumpeters and Laughers, which likewise do not differ much in any other character) coo in the same peculiar manner, unlike the voice of any other wild pigeon. All the coloured breeds display the same peculiar metallic tints on the breast, a character far from general with pigeons. Each race presents nearly the same range of variation in colour; and in most of the races we have the same singular correlation between the development of down in the young and the future colour of plumage. All have the proportional length of their toes, and of their primary wing-feathers, nearly the same,—characters which are apt to differ in the several members of the Columbidæ. In those races which present some remarkable deviation of structure, such as in the tail of Fantails, crop of Pouters, beak of Carriers and Tumblers, etc., the other parts remain nearly unaltered. Now every naturalist will admit that it would be scarcely possible to pick out a dozen natural species in any family which should agree closely in habits and in general structure, and yet should differ greatly in a few characters alone. This fact is explicable through the doctrine of natural selection; for each successive modification of structure in each natural species is preserved, solely because it is of service; and such modifications when largely accumulated imply a great change in the habits of life, and this will almost certainly lead to other changes of structure throughout the whole organisation. On the other hand, if the several races of the pigeon have been produced by man through selection and variation, we can readily understand how it is that they should still all resemble each other in habits and in those many characters which man has not cared to modify, whilst they differ to so prodigious a degree in those parts which have struck his eye or pleased his fancy.

Besides the points above enumerated, in which all the domestic
races resemble _C. livia_ and each other, there is one which
deserves special notice. The wild rock-pigeon is of a slaty-blue
colour; the wings are crossed by two bars; the croup varies in
colour, being generally white in the pigeon of Europe, and blue in
that of India; the tail has a black bar close to the end, and the
outer webs of the outer tail-feathers are edged with white, except
near the tips. These combined characters are not found in any wild
pigeon besides _C. livia._ I have looked carefully through the
great collections of pigeons in the British Museum, and I find that
a dark bar at the end of the tail is common; that the white edging
to the outer tail-feathers is not rare; but that the white croup is
extremely rare, and the two black bars on the wings occur in no
other pigeon, excepting the alpine _C. leuconota_ and _C.
rupestris_ of Asia. Now if we turn to the domestic races, it is
highly remarkable, as an eminent fancier, Mr. Wicking, observed to
me, that, whenever a blue bird appears in any race, the wings
almost invariably show the double black bars.[23] The primary
wing-feathers may be white or black, and the whole body may be of
any colour, but if the wing-coverts are blue, the two black bars
are sure to appear. I have myself seen, or acquired trustworthy
evidence, as given below,[24] of blue birds with black bars on the
wing, with the croup either white or very pale or dark blue, with
the tail having a terminal black bar, and with the outer feathers
externally edged with white or very pale coloured, in the following
races, which, as I carefully observed in each case, appeared to be
perfectly true: namely, in Pouters, Fantails, Tumblers, Jacobins,
Turbits, Barbs, Carriers, Runts of three distinct varieties,
Trumpeters, Swallows, and in many other toy-pigeons, which as being
closely allied to _C. livia,_ are not worth enumerating. Thus we
see that, in purely-bred races of every kind known in Europe, blue
birds occasionally appear having all the marks which characterise
_C. livia,_ and which concur in no other wild species. Mr. Blyth,
also, has made the same observation with respect to the various
domestic races known in India.

Certain variations in the plumage are equally common in the wild
_C. livia,_ in dovecot-pigeons, and in all the most highly modified
races. Thus, in all, the croup varies from white to blue, being
most frequently white in Europe, and very generally blue in
India.[25] We have seen that the wild _C. livia_ in Europe, and
dovecots in all parts of the world, often have the upper
wing-coverts chequered with black; and all the most distinct races,
when blue, are occasionally chequered in precisely the same manner.
Thus I have seen Pouters, Fantails, Carriers, Turbits, Tumblers
(Indian and English), Swallows, Bald-pates, and other toy-pigeons
blue and chequered; and Mr. Esquilant has seen a chequered Runt. I
bred from two pure blue Tumblers a chequered bird.

The facts hitherto given refer to the occasional appearance in pure
races of blue birds with black wing-bars, and likewise of blue and
chequered birds; but it will now be seen that when two birds
belonging to distinct races are crossed, neither of which have, nor
probably have had during many generations, a trace of blue in their
plumage, or a trace of wing-bars and the other characteristic
marks, they very frequently produce mongrel offspring of a blue
colour, sometimes chequered, with black wing-bars, etc.; or if not
of a blue colour, yet with the several characteristic marks more or
less plainly developed. I was led to investigate this subject from
MM. Boitard and Corbié[26] having asserted that from crosses
between certain breeds it is rare to get anything but bisets or
dovecot pigeons, which, as we know, are blue birds with the usual
characteristic marks. We shall hereafter see that this subject
possesses, independently of our present object, considerable
interest, so that I will give the results of my own trials in full.
I selected for experiment races which, when pure, very seldom
produce birds of a blue colour, or have bars on their wings and
tail.

The Nun is white, with the head, tail, and primary wing-feathers black; it is a breed which was established as long ago as the year 1600. I crossed a male Nun with a female red common Tumbler, which latter variety generally breeds true. Thus neither parent had a trace of blue in the plumage, or of bars on the wing and tail. I should premise that common Tumblers are rarely blue in England. From the above cross I reared several young: one was red over the whole back, but with the tail as blue as that of the rock-pigeon; the terminal bar, however, was absent, but the outer feathers were edged with white: a second and third nearly resembled the first, but the tail in both presented a trace of the bar at the end: a fourth was brownish, and the wings showed a trace of the double bar: a fifth was pale blue over the whole breast, back, croup, and tail, but the neck and primary wing-feathers were reddish; the wings presented two distinct bars of a red colour; the tail was not barred, but the outer feathers were edged with white. I crossed this last curiously coloured bird with a black mongrel of complicated descent, namely, from a black Barb, a Spot, and Almond-tumbler, so that the two young birds produced from this cross included the blood of five varieties, none of which had a trace of blue or of wing and tail-bars: one of the two young birds was brownish-black, with black wing-bars; the other was reddish-dun, with reddish wing-bars, paler than the rest of the body, with the croup pale blue, the tail bluish with a trace of the terminal bar.

Mr. Eaton[27] matched two Short-faced Tumblers, namely, a splash
cock and kite hen (neither of which are blue or barred), and from
the first nest he got a perfect blue bird, and from the second a
silver or pale blue bird, both of which, in accordance with all
analogy, no doubt presented the usual characteristic marks.

I crossed two male black Barbs with two female red Spots. These
latter have the whole body and wings white, with a spot on the
forehead, the tail and tail-coverts red; the race existed at least
as long ago as 1676, and now breeds perfectly true, as was known to
be the case in the year 1735.[28] Barbs are uniformly-coloured
birds, with rarely even a trace of bars on the wing or tail; they
are known to breed very true. The mongrels thus raised were black
or nearly black, or dark or pale brown, sometimes slightly piebald
with white: of these birds no less than six presented double
wing-bars; in two the bars were conspicuous and quite black; in
seven some white feathers appeared on the croup; and in two or
three there was a trace of the terminal bar to the tail, but in
none were the outer tail-feathers edged with white.

I crossed black Barbs (of two excellent strains) with purely-bred, snow-white Fantails. The mongrels were generally quite black, with a few of the primary wing and tail feathers white: others were dark reddish-brown, and others snow-white: none had a trace of wing-bars or of the white croup. I then paired together two of these mongrels, namely, a brown and black bird, and their offspring displayed wing-bars, faint, but of a darker brown than the rest of body. In a second brood from the same parents a brown bird was produced, with several white feathers confined to the croup.

I crossed a male dun Dragon belonging to a family which had been
dun- coloured without wing-bars during several generations, with a
uniform red Barb (bred from two black Barbs); and the offspring
presented decided but faint traces of wing-bars. I crossed a
uniform red male Runt with a White trumpeter; and the offspring had
a slaty-blue tail with a bar at the end, and with the outer
feathers edged with white. I also crossed a female black and white
chequered Trumpeter (of a different strain from the last) with a
male Almond-tumbler, neither of which exhibited a trace of blue, or
of the white croup, or of the bar at end of tail: nor is it
probable that the progenitors of these two birds had for many
generations exhibited any of these characters, for I have never
even heard of a blue Trumpeter in this country, and my
Almond-tumbler was purely bred; yet the tail of this mongrel was
bluish, with a broad black bar at the end, and the croup was
perfectly white. It may be observed in several of these cases, that
the tail first shows a tendency to become by reversion blue; and
this fact of the persistency of colour in the tail and
tail-coverts[29] will surprise no one who has attended to the
crossing of pigeons.

The last case which I will give is the most curious. I paired a mongrel female Barb-fantail with a mongrel male Barb-spot; neither of which mongrels had the least blue about them. Let it be remembered that blue Barbs are excessively rare; that Spots, as has been already stated, were perfectly characterised in the year 1676, and breed perfectly true; this likewise is the case with white Fantails, so much so that I have never heard of white Fantails throwing any other colour. Nevertheless the offspring from the above two mongrels was of exactly the same blue tint as that of the wild rock-pigeon from the Shetland Islands over the whole back and wings; the double black wing-bars were equally conspicuous; the tail was exactly alike in all its characters, and the croup was pure white; the head, however, was tinted with a shade of red, evidently derived from the Spot, and was of a paler blue than in the rock-pigeon, as was the stomach. So that two black Barbs, a red Spot, and a white Fantail, as the four purely-bred grandparents, produced a bird exhibiting the general blue colour, together with every characteristic mark, the wild _Columba livia._

With respect to crossed breeds frequently producing blue birds chequered with black, and resembling in all respects both the dovecot-pigeon and the chequered wild variety of the rock-pigeon, the statement before referred to by MM. Boitard and Corbié would almost suffice; but I will give three instances of the appearance of such birds from crosses in which one alone of the parents or great-grandparents was blue, but not chequered. I crossed a male blue Turbit with a snow-white Trumpeter, and the following year with a dark, leaden-brown, Short-faced Tumbler; the offspring from the first cross were as perfectly chequered as any dovecot-pigeon; and from the second, so much so as to be nearly as black as the most darkly chequered rock-pigeon from Madeira. Another bird, whose great-grandparents were a white Trumpeter, a white Fantail, a white Red-spot, a red Runt, and a blue Pouter, was slaty-blue and chequered exactly like a dovecot-pigeon. I may here add a remark made to me by Mr. Wicking, who has had more experience than any other person in England in breeding pigeons of various colours: namely, that when a blue, or a blue and chequered bird, having black wing- bars, once appears in any race and is allowed to breed, these characters are so strongly transmitted that it is extremely difficult to eradicate them.

What, then, are we to conclude from this tendency in all the chief domestic races, both when purely bred and more especially when intercrossed, to produce offspring of a blue colour, with the same characteristic marks, varying in the same manner, as in _Columbia livia_? If we admit that these races are all descended from _C. livia,_ no breeder will doubt that the occasional appearance of blue birds thus characterised is accounted for on the well-known principle of “throwing back” or reversion. Why crossing should give so strong a tendency to reversion, we do not with certainty know; but abundant evidence of this fact will be given in the following chapters. It is probable that I might have bred even for a century pure black Barbs, Spots, Nuns, white Fantails, Trumpeters, etc., without obtaining a single blue or barred bird; yet by crossing these breeds I reared in the first and second generation, during the course of only three or four years, a considerable number of young birds, more or less plainly coloured blue, and with most of the characteristic marks. When black and white, or black and red birds, are crossed, it would appear that a slight tendency exists in both parents to produce blue offspring, and that this, when combined, overpowers the separate tendency in either parent to produce black, or white, or red offspring.

If we reject the belief that all the races of the pigeon are the modified descendants of _C. livia,_ and suppose that they are descended from several aboriginal stocks, then we must choose between the three following assumptions: firstly, that at least eight or nine species formerly existed which were aboriginally coloured in various ways, but have since varied in exactly the same manner so as to assume the colouring of _C. livia_; but this assumption throws not the least light on the appearance of such colours and marks when the races are crossed. Or secondly, we may assume that the aboriginal species were all coloured blue, and had the wing-bars and other characteristic marks of _C. livia,_—a supposition which is highly improbable, as besides this one species no existing member of the Columbidæ presents these combined characters; and it would not be possible to find any other instance of several species identical in plumage, yet as different in important points of structure as are Pouters, Fantails, Carriers, Tumblers, etc. Or lastly, we may assume that all the races, whether descended from _C. livia_ or from several aboriginal species, although they have been bred with so much care and are so highly valued by fanciers, have all been crossed within a dozen or score of generations with _C. livia,_ and have thus acquired their tendency to produce blue birds with the several characteristic marks. I have said that it must be assumed that each race has been crossed with _C. livia_ within a dozen, or, at the utmost, within a score of generations; for there is no reason to believe that crossed offspring ever revert to one of their ancestors when removed by a greater number of generations. In a breed which has been crossed only once, the tendency to reversion will naturally become less and less in the succeeding generations, as in each there will be less and less of the blood of the foreign breed; but when there has been no cross with a distinct breed, and there is a tendency in both parents to revert to some long-lost character, this tendency, for all that we can see to the contrary, may be transmitted undiminished for an indefinite number of generations. These two distinct cases of reversion are often confounded together by those who have written on inheritance.

Considering, on the one hand, the improbability of the three assumptions which have just been discussed, and, on the other hand, how simply the facts are explained on the principle of reversion, we may conclude that the occasional appearance in all the races, both when purely bred and more especially when crossed, of blue birds, sometimes chequered, with double wing-bars, with white or blue croups, with a bar at the end of the tail, and with the outer tail-feathers edged with white, affords an argument of the greatest weight in favour of the view that all are descended from _Columba livia,_ including under this name the three or four wild varieties or sub-species before enumerated.

To sum up the six foregoing arguments, which are opposed to the belief that the chief domestic races are the descendants of at least eight or nine or perhaps a dozen species; for the crossing of any less number would not yield the characteristic differences between the several races. _ Firstly,_ the improbability that so many species should still exist somewhere, but be unknown to ornithologists, or that they should have become within the historical period extinct, although man has had so little influence in exterminating the wild _C. livia. Secondly,_ the improbability of man in former times having thoroughly domesticated and rendered fertile under confinement so many species. _Thirdly,_ these supposed species having nowhere become feral. _Fourthly,_ the extraordinary fact that man should, intentionally or by chance, have chosen for domestication several species, extremely abnormal in character; and furthermore, the points of structure which render these supposed species so abnormal being now highly variable. _Fifthly,_ the fact of all the races, though differing in many important points of structure, producing perfectly fertile mongrels; whilst all the hybrids which have been produced between even closely allied species in the pigeon-family are sterile. _Sixthly,_ the remarkable statements just given on the tendency in all the races, both when purely bred and when crossed, to revert in numerous minute details of colouring to the character of the wild rock-pigeon, and to vary in a similar manner. To these arguments may be added the extreme improbability that a number of species formerly existed, which differed greatly from each other in some few points, but which resembled each other as closely as do the domestic races in other points of structure, in voice, and in all their habits of life. When these several facts and arguments are fairly taken into consideration, it would require an overwhelming amount of evidence to make us admit that the chief domestic races are descended from several aboriginal stocks; and of such evidence there is absolutely none.

The belief that the chief domestic races are descended from several wild stocks no doubt has arisen from the apparent improbability of such great modifications of structure having been effected since man first domesticated the rock-pigeon. Nor am I surprised at any degree of hesitation in admitting their common parentage: formerly, when I went into my aviaries and watched such birds as Pouters, Carriers, Barbs, Fantails, and Short-faced Tumblers, etc., I could not persuade myself that all had descended from the same wild stock, and that man had consequently in one sense created these remarkable modifications. Therefore I have argued the question of their origin at great, and, as some will think, superfluous length.

Finally, in favour of the belief that all the races are descended
from a single stock, we have in _Columba livia_ a still existing
and widely distributed species, which can be and has been
domesticated in various countries. This species agrees in most
points of structure and in all its habits of life, as well as
occasionally in every detail of plumage, with the several domestic
races. It breeds freely with them, and produces fertile offspring.
It varies in a state of nature,[30] and still more so when
semi-domesticated, as shown by comparing the Sierra Leone pigeons
with those of India, or with those which apparently have run wild
in Madeira. It has undergone a still greater amount of variation in
the case of the numerous toy-pigeons, which no one supposes to be
descended from distinct species; yet some of these toy-pigeons have
transmitted their character truly for centuries. Why, then, should
we hesitate to believe in that greater amount of variation which is
necessary for the production of the eleven chief races? It should
be borne in mind that in two of the most strongly-marked races,
namely, Carriers and Short-faced Tumblers, the extreme forms can be
connected with the parent-species by graduated differences not
greater than those which may be observed between the
dovecot-pigeons inhabiting different countries, or between the
various kinds of toy-pigeons,—gradations which must certainly be
attributed to variation.