Chapter XXII: Part 22

Yet it so happens that the great zoogeographical regions of the world, now more or less generally accepted, have been based upon the distribution of birds. The whole subject was properly introduced by Treviranus,[1] who in his large philosophical work devotes considerable space to the "geographical distribution of animals." Next we have to mention F. Tiedemann,[2] the Heidelberg anatomist, who has been generally ignored, although he surpassed many a recent zoogeographer by the wide view he took of the problem; in fact he was the first to connect distribution with environmental or bionomic factors; e.g. the remark on p. 481 of his work that "the countries of the East Indian flora have no kinds of birds in common with America which are vegetable feeders." L.K. Schmarda[3] divided the land into twenty-one realms, characterizing these mainly by their birds. P.L. Sclater[4] was the first to divide the world into a few great "regions," the Palaearctic, Ethiopian, Indian and Australian forming one group, the "Old World" (_Palaeogaea_); and the Nearctic and Neotropical forming a second, the New World (_Neogaea_). Birds being of all animals most particularly adapted for extended and rapid locomotion, it became necessary for him to eliminate from his consideration those groups, be they small or large, which are of more or less universal occurrence, and to ground his results on what was at that time commonly known as the order Insessores or Passeres, comprehending the orders now differentiated as Passeriformes, Coraciiformes and Cuculiformes, in other words the mass of arboreal birds. His six main divisions--practically adopted by A.R. Wallace[5] in his epoch-making work--are excellent, taken separately. They express the main complexes of land with their dependencies in well-chosen terms; for instance the "Neotropical region" stands short for South and Central America with the Antilles.

But these six divisions of Sclater and Wallace are not all equivalent, only some are of primary importance; they require co- and sub-ordination. This most important advance was made by T.H. Huxley.[6] Some of the "regions" have now to be called subregions, e.g. the Nearctic and the Palaearctic. The reduction of the Oriental to a subregion, with consequent "provincial" rank of its main subdivisions, will probably be objected to, but these are matters of taste and prejudice. Above all it should be borne in mind that nearly all the last subdivisions or provinces are of very little real value and most of them are inapplicable to other classes of animals.

Besides some occasional references in the text, only a few more of the
general works dealing with the distribution of birds can here be
mentioned. Especial attention has to be drawn to the article
"Geographical Distribution," in Newton's _Dictionary of Birds_. See
also A. Heilprin, _The Geographical and Zoological Distribution of
Animals_ (New York, 1887); W. Marshall and A. Reichenow, two maps with
much detail, although badly arranged, in Berghaus' _Physikalischer
Atlas_, pt. vi. (_Atlas d. Thierverbreitung_), (Gotha, 1887); A.
Reichenow, "Die Begrenzung zoogeographischer Regionen vom
ornithologischen Standpunkte," _Zoolog. Jahrb._ iii., 1888, pp.
671-704, pl. xxvi.; E.L. Trouessart, _La Geographie zoologique_.
(Paris, 1890).

The scheme adopted in the following account stands as follows:--

(A) AUSTROGAEA or I. Australian Region:
New Zealand subregion.
Australian "
Papuan "

(B) NEOGAEA or II. Neotropical Region
Antillean subregion
Columbian "
Patagonian "

(C) ARCTOGAEA
III. Holarctic Region
Nearctic Subregion
Palaearctic "

IV. Palaeotropical Region
Ethiopian Subregion
Oriental "

In the following account the characterization of the various regions and subregions has to a very great extent been adopted from Newton's article in his _Dictionary of Birds_, and from the chapter on distribution in the article on "Birds" in the _Encyclopaedia Britannica_, 9th edition. This applies especially ~~ to those instances in which the members of families, genera and species are mentioned. The families are those which are enumerated in Garow's classification. The numbers of genera and species of birds are, of course, a matter of personal inclination. If we take a moderate computation the number of recent species may be taken at 10,000-11,000.[7] Dr R.B. Sharpe increases their number to about 15,000 in the _New Hand-List of Birds_, published by the British Museum. In the first two volumes fossil birds, occasionally based upon a fragmentary bone only, are also included.

(A) AUSTROGAEA, the Australian region in the wider sense, with the
Papuan, Australian and New Zealand subregions, including also
Polynesia. We may here quote Newton (_Encyclopaedia Britannica_, 9th
ed., "Birds," p. 738) on the remarkable differences between this
region and the rest of the Old World:--"The prevalent zoological
features of any Region are of two kinds--negative and positive. It is
therefore just as much the business of the zoogeographer, who wishes
to arrive at the truth, to ascertain what groups of animals are
wanting in any particular locality (altogether independently of its
extent) as to determine those which are forthcoming there. Of course,
in the former case it would be absurd to regard as a physical feature
of any great value the absence from a district of groups which do not
occur except in its immediate neighbourhood; but when we find that
certain groups, though abounding in some part of the vicinity, either
suddenly cease from appearing or appear only in very reduced numbers,
and occasionally in abnormal forms, the fact obviously has an
important bearing. Now, mere geographical considerations, taken from
the situation and configuration of the islands of the so-called Indian
or Malay Archipelago, would indicate that they extended in an unbroken
series from the shores of the Strait of Malacca to the southern coast
of New Guinea, which confronts that of north Australia in Torres
Strait, or even farther to the eastward. Indeed, the very name
Australasia, often applied to this part of the world, would induce the
belief that all the countless islands, be they large or small--and
some of them are among the largest on the globe--were but a southern
prolongation of the mainland of Asia. But so far from this being the
case a very definite barrier is interposed. A strait, some 15 m. or so
in width, and separating the two fertile but otherwise insignificant
islands of Bali and Lombok, makes such a frontier as can hardly be
shown to exist elsewhere. The former of these two islands belongs to
the Indian Region, the latter to the Australian, and between them
there is absolutely no true transition--that is, no species are common
to both which cannot be easily accounted for by the various accidents
and migrations that in the course of time must have tended to mingle
the productions of islands so close to one another. The faunas of the
two are as absolutely distinct as those of South America and Africa,
and it is only because they are separated by a narrow strait instead
of the broad Atlantic that they have become so slightly connected by
the interchange of a few species and genera.

"Now, first, of the forms of birds which are prevalent throughout the
Indian Region, but are entirely wanting in the Australian, we have at
once the bulbuls (_Ixidae_), very characteristic of most parts of
Africa and Asia, including the sub-group _Phyllornithinae_, which is
peculiar to the Indian Region; the widely-spread families of barbets
(_Megalaeminae_) and vultures (_Vulturidae_); and the pheasants
(_Phasianidae_), which attain so great a development in various parts
of the Asiatic continent and islands that there must their home be
regarded as fixed. Some naturalists would add the finches
(_Fringillidae_), rightly if we assume that the _Ploceidae_ or weavers
constitute a separate family. Then, of forms which are but weakly
represented, we have the otherwise abundant thrushes (_Turdidae_),
and, above all, the woodpeckers (_Picidae_), of which only very few
species, out of 400, just cross the boundary and occur in Lombok,
Celebes or the Moluccas, but are unknown elsewhere in the region."

But the Australian region is also remarkable for its ornithic
singularity. All the existing Ratitae (with the exception of the
ostriches of Africa and South America, belonging to the genera
_Struthio_ and _Rhea_, and comprising at most but five species) are
found in Austrogaea and nowhere else. Of the Passeres the
honey-suckers (_Meliphagidae_) are most characteristic, and, abounding
in genera and species, extend to almost every part of the region, yet
only one species of _Ptilotis_ oversteps its limits, crossing the sea
from Lombok to Bali. Other peculiar families are much more confined.
But the positive characteristics of the region as a whole are not its
peculiar forms alone; there are at least four families which, being
feebly represented elsewhere, here attain the maximum of development.
Such are the thick-headed shrikes (_Pachycephalidae_), the
caterpillar-eaters (_Campephagidae_), the flower-peckers
(_Dicaeidae_), and the swallow-flycatchers (_Artamidae_). Besides
these, three or perhaps four groups, though widely distributed
throughout the world, arrive in the Australian region at their
culmination, presenting an abundance of most varied forms. These are
the weaver-birds (_Ploceidae_), and the moreporks (_Podargidae_), but
especially the kingfishers (_Alcedinidae_) and the pigeons
(_Columbidae_), the species belonging to the two last obtaining in
this region a degree of prominence and beauty which is elsewhere
unequalled.

The boundaries of the subregions are not well defined.

The _New Zealand Subregion_, considered by Professors Newton and
Huxley and various other zoogeographers as deserving the rank of a
region, is, and to all appearance has long been, more isolated than
any other portion of the globe. Besides the three larger islands
numerous satellites belong to the subregion, as Lord Howe, Norfolk and
Kermadec islands, with the Chatham, Auckland and Macquarie groups. The
main affinities of the avifauna are, of course, Australian. The most
extraordinary feature is unquestionably the former existence of the
gigantic Dinornithes or moas (q.v.) and, another family of Ratitae,
the weird-looking kiwis or Apteryges, which are totally unlike any
other existing birds. Of other peculiar genera it will suffice to
mention only the more remarkable. _Rallidae_ present the very
noteworthy woodhens, _Ocydromus_, and the takahe, _Notornis_, which is
almost extinct. The widely-spread plovers, _Charadriidae_, have two
not less singular generic developments, _Thinornis_, and the
extraordinary wrybill, _Anarhynchus_. There is an owl, type of the
genus _Sceloglaux_. Of parrots, _Stringops_, the kakapo or owl-parrot,
is certainly peculiar, while _Nestor_ constitutes a peculiar subfamily
of the brush-tongued parrots or _Trichoglossidae_. _Xenicus_ and
_Acanthositta_ form a little family of truly mesomyodean Passeres
Clamatores. Of the _Meliphagidae_ the genera _Prosthemadera_,
_Pogonornis_ and _Anthornis_ are peculiar. The starlings, _Sturnidae_,
are represented by _Callaeas_, _Creadion_ and the very abnormal
_Heterolocha_. The gallinaceous birds are represented by a quail,
_Coturnix novae zealandiae_, now exterminated. A large flightless
goose, _Cnemiornis_, allied to the Australian _Cereopsis_, and the
gigantic rapacious _Harpagornis_, have died out recently, with the
moas. In all, there is a wonderful amount of specialization, though
perhaps in a very straight line from generalized forms; but the
affinity to Australian or Polynesian types is in many cases clearly
traceable, and it cannot be supposed but that these last are of
cognate origin with those of New Zealand. A very long period of
isolation must have been required to produce the differences so
manifestly to be observed, but a few forms seem at rare intervals to
have immigrated, and this immigration would appear to be kept up to
our own day, as shown by the instance of _Zosterops lateralis_, which
is said to have lately made its first appearance, and to have
established itself in the country, as well as by the fact of two
cuckoos, the widely-ranging _Eudynamis taitensis_ and _Chrysococcyx
lucidus_, which are annual visitors.

_Polynesia_ forms, of course, part of Austrogaea. Its extent is so
vast that it necessarily contains some peculiar, outlying forms, so to
say forgotten, which in their long-continued isolation have
specialized themselves. For instance, the kagu (_Rhinochetus_) of New
Caledonia, a queerly specialized form with Gruine affinities pointing
only to South America. The toothbilled pigeon (_Didunculus_) is
restricted to Samoa. Most interesting is the avifauna of the Sandwich
islands; entirely devoid of Psittaci and of Coraciiformes, these
islands show an extraordinary development of its peculiar family
_Drepanidae_, which are probably of South or Central American descent.
_Acrulocercus_ is a Meliphagine, and a peculiar genus. There are a
raven (_Corvus_), a coot (_Fulica_), the well-known Sandwich island
goose (_Bernicla sandvicensis_), now very commonly domesticated in
Europe; and some flycatchers and thrushlike birds.

The _Australian Subregion_ comprises Australia and Tasmania. In the
north it is influenced, of course, by its proximity to Papuasia,
whence there is a considerable admixture of genera which do not
proceed beyond the tropics, and of these _Casuarius_ is a striking
example. The Cape York peninsula practically belongs to Papuasia. As a
whole, Australia is rich in parrots, of which it has several very
peculiar forms, but Picarians in old-fashioned parlance, of all
sorts--certain kingfishers excepted--are few in number, and the
pigeons are also comparatively scarce, no doubt because of the many
arboreal predaceous marsupials. The continent, however, possesses the
two important genera of the _Pseudoscines_, namely the lyre-birds
(_Menura_) and the scrub-birds (_Atrichia_). Among the more curious
forms of other land-birds may be especially mentioned the
_Megapodiidae_, _Lipoa_ and _Talegallus_, the rail _Tribonyx_ and
_Pedionomus_, which represents the otherwise palaeotropical _Turnices_
in Australia. The presence of bustards (_Eupodotis_) is a curious
example of interrupted distribution, since none other of the
_Otididae_ are found nearer than India. The Ratitae are represented by
two species of emeu (_Dromaeus_), besides the cassowary of Cape York
peninsula, and the extinct _Dromornis_ and _Genyornis_ with its
enormous skull.

The _Papuan Subregion_, chiefly New Guinea with its dependencies, the
Timor group of islands, the Moluccas and Celebes. On the whole its
avifauna presents some very remarkable features. Its most distinctive
characteristic is the presence of the birds of paradise, which are
almost peculiar to it; for, granting that the bower-birds,
_Chlamydodera_ and others, of Australia, belong to the same family,
they are far less highly specialized than the beautiful and
extraordinary forms which are found, within very restricted limits, in
the various islands of the subregion. Another chief feature is the
extraordinary development of the cassowaries, the richness and
specialization of the kingfishers, parrots, pigeons, honey-suckers and
some remarkable flycatchers. It has several marked deficiencies
compared with Australia, among which are the babblers (_Timeliidae_),
weaver birds (_Ploceidae_), the _Platycercinae_ among parrots, diurnal
birds of prey and the emeus. As a whole, the birds of Papua are
remarkable for their brilliance of plumage, or their metallic
colouring. The birds of paradise, the racquet-tailed kingfishers,
_Tanysiptera_, the largest and smallest of parrots, _Calyptdrhynchiis_
and _Nasiterna_, and the great crowned pigeons, _Goura_, are very
characteristic; and so are the various Megapodes.

(B) NEOGAEA, or the _Neotropical region._--Excepting towards the
north, where, in Mexico, it meets, and inosculates with the Nearctic
subregion, the boundaries of the Neotropical region are simple enough
to trace, comprehending as it does the whole of South America and all
Central America; besides including the Falkland islands to the
south-east and the Galapagos under the equator to the west, as well as
the Antilles or West India islands up to the Florida channel.

Owing to the comparatively scanty number of harmful mammalian types,
the birds play a considerable part in this large region, and some
authorities consider its avifauna the richest in the world. The entire
number of species amounts to about 3600. Of these 2000, or a good deal
more than half, belong to the order Passeriformes. But the
characteristic nature of the avifauna is more clearly brought out when
we learn that of the 2000 species just mentioned only about 1070
belong to the higher suborder of Oscines, that means to say, nearly
one-half belong to the lower suborder Clamatores. This is a state of
things which exists nowhere else; for except in Australia, where a few
indigenous and peculiar low non-Oscines are found, and in the Nearctic
country, whither one family of Clamatores, viz. the _Tyrannidae_, has
evidently been led by the geographical continuity of its soil with
that of the Neotropical region, such forms do not occur elsewhere.
Accordingly their disproportionate prevalence in South America points
unerringly to the lower rank of the avifauna of the region as a whole,
and therefore to the propriety of putting it next in order to that of
the Australian region, the general fauna of which is admittedly the
lowest in the world. Huxley has urged with his wonted perspicuity the
alliance of these two regions as _Notogaea_, basing his opinion,
besides other weighty evidence, in great measure on the evidence
afforded by the two main sections of the Galli, viz. the
_Peristeropodes_ and the _Alectoropodes_, the former composed of the
families _Megapodiidae_, almost wholly Australian, and the _Cracidae_,
entirely Neotropical. (Cf. _P.Z.S._, 1868. pp. 294-319.)

Leaving, however, this matter as in some degree hypothetical, we have
as genera, families, or perhaps even larger groups, a great many very
remarkable forms which are characteristic of, or peculiar to, the
Neotropical region in part, if not as a whole. Of families we find
twenty-three, or maybe more, absolutely restricted thereto, besides at
least eight which, being peculiar to the New World, extend their range
into the Nearctic region, but are there so feebly developed that their
origin may be safely ascribed to the southern portion of America.
First in point of importance comes the extraordinarily beautiful
family of humming-birds (_Trochilidae_), with nearly 150 genera (of
which only three occur in the Nearctic region) and more than 400
species. Then the tyrants (_Tyrannidae_), with more than seventy
genera (ten of which range into the northern region), and over 300
species. To these follow the tanagers (_Tanagndae_), with upwards of
forty genera (only one of which crosses the border), and about 300
species; the piculules (_Dendrocolaptidae_), with as many genera, and
over 200 species; the ant-thrushes, (_Formicariidae_), with more than
thirty genera, and nearly 200 species; together with other groups
which, if not so large as those just named, are yet just as well
defined, and possibly more significant, namely, the tapaculos
(_Pteroptochidae_), the toucans (_Rhamphastidae_), the jacamars
(_Galbulidae_), the motmots (_Monotidae_), the todies (_Todidae_), the
trumpeters (_Psophiidae_), and the screamers (_Palamedeidae_); besides
such isolated forms as the seriema (_Cariama_), and the sun-bittern
(_Eurypyga_).

The nature of the South American avifauna will perhaps become still
more evident if we arrange the characteristic members as follows:--

1. Birds which are restricted to, probably indigenous of the region:
_Rhea_; _Palamedea_ and _Chauna_, the screamers; _Tinami_; _Psophia,
Dicholophus, Eurypyga, Heliornis_ of the Gruiform assembly;
_Thinocorys_ and _Attagis; Cracidae; Opisthocomus_; of parrots _Ara_
and _Conurus_ with their allies; _Monotidae_, incl. _Todus;
Steatornis; Galbulinae_ and _Bucconinae; Rhamphastidae; Formicariidae,
Pteroptochidae_, and of the _Tyrannidae_ the _Cotinginae_.

2. Birds which are indigenous, but extend far into North America:
_Cathartae, Trochilidae, Tyrannidae_.

3. Birds which are originally immigrants from North America:
_Podicipedidae_, with the flightless _Centropelma_ on Lake Titicaca;
_Ceryle_, the only genus of kingfishers in the New World; all the
_Oscines_.

More or less cosmopolitan groups like herons, _Falconidae, Anseres,
Columbae, &c._, and circumtropical families like _Parridae,
Trogonidae, Capitonidae_, are to be excluded from these lists as
indifferent. The differences between the Neotropical avifauna and that
of North America are fundamental and prove the independence or
superior value of the Neotropical region as one of the principal
realms.

It is difficult to subdivide the Neotropical region into subregions;
the best suggestion is that of Newton: _Antillean_, with the exception
of the islands of Trinidad and Tobago, as well as those which lie on
the northern coast of South America; _Patagonian_, including Chile and
part of Peru; _Columbian_, comprising the rest of the continent and
also Central America.

The _Antillean Subregion_ is in many respects one of the most
suggestive and interesting, comparatively small though it be. For
narrow as are the channels between Cuba and the opposite coast of
Central America, between the Bahamas and Florida, and between Grenada
and Tobago, the fauna of the Antillean chain, instead of being a
mixture of that of the almost contiguous countries, differs much from
all, and exhibits in some groups a degree of speciality which may be
not unfitly compared with that of oceanic islands. Except such as are
of coral formation, the Antilles are hilly, not to say mountainous,
their summits rising in places to an elevation of 8000 ft., and nearly
all, prior to their occupation by Europeans, were covered with
luxuriant forest, which, assisting in the collection and condensation
of the clouds brought by the trade winds, ensured its own vitality by
precipitating frequent and long-continued rains upon the fertile soil.
Under such conditions we might expect to find an extremely plentiful
animal population, one as rich as that which inhabits the same
latitudes in Central America, not many degrees farther to the west;
but no instance perhaps can be cited which shows more strikingly the
difference between a continental and an insular fauna, since, making
every allowance for the ravages of cultivation by civilized man, the
contrary is the case, and possibly no area of land so highly favoured
by nature is so poorly furnished with the higher forms of animal life.
Here, as over so large a portion of the Australian region, we find
birds constituting the supreme class--the scarcity of mammals being
accounted for in some measure as a normal effect of insularity.

There is one peculiar subfamily, _Todinae_, represented by only four
species of _Todus_. We note the absence of _Ratitae, Tinami, Cracidae,
Rhamphastidae_, and any of those gruiform genera which are so
characteristic of the continent. There is no family of birds common to
the Nearctic area and the Antillean subregion without occurring also
in other parts of the Neotropical region, a fact which proves its
affinity to the latter.

The _Patagonian Subregion_, most extratropical, is naturally devoid of
a good many typically tropical birds, or these are but poorly
represented, for instance _Caerebidae, Mniotiltidae, Tanagridae,
Vireonidae_. On the other hand some of the most characteristic
features of the whole region are here well represented, e.g. _Rhea,
Tinami, Chauna, Dicholophus, Attagis, Pteroptochidae_, and indeed
therein we find some of the best evidence of the antiquity of its
population, both recent and extinct (cf. the numerous fossils of the
Santa Cruz formation), and also the nearest resemblance to the fauna
of Austrogaea.

(C) ARCTOGAEA is Huxley's well-chosen term for all the rest of the
world (including the Nearctic, Palaearctic, Indian and Ethiopian
regions of P.L. Sclater) in opposition to Notogaea. Faunistically,
although not geographically, the Nearctic and Palaearctic areas must
form the two subdivisions of one great unit, for which the "Holarctic
region" is now the generally accepted term.

The HOLARCTIC REGION, comprising North America and the extratropical
mass of land of the Old World, may from an ornithological point of
view be characterized by the Colymbi, _Alcidae, Gallidae_ or
Alectoropodous Galli, and the Oscines, which have here reached their
highest development; while Ratitae, Tinami, Psittaci, and non-Oscine
Passeres (with the exception of _Tyrannidae_ extending into North
America and _Conurus carolinensis_) are absent.

_Nearctic Subregion._--The close affinity of North America with the
Palaearctic avifauna becomes at once apparent if we exclude those
groups of birds which we have good reason to believe have their
original home in the Neotropical region, notably numerous
_Tyrannidae_, humming-birds and the turkey-buzzards.

The following groups may be mentioned as characteristic and typically
American, and, since we consider them as comparatively recent
immigrants into the Neotropical region, as originally peculiar to the
Nearctic area: _Mniotiltidae, Vireonidae, Icteridae, Meleagris_ and
various _Tetraoninae_. Restricted to and peculiar to the sub-region is
only the little Oscine family of _Chamaeidae_, restricted to the coast
district of California. "More than one-third of the genera of Nearctic
birds are common also to the Palaearctic subregion. If we take the
number of Nearctic species at 700, which is perhaps an exaggeration,
and that of the Palaearctic at 850, we find that, exclusive
stragglers, there are about 120 common to the two areas. Nearly 20
more are properly Palaearctic, but occasionally occur in America, and
about 50 are Nearctic, which from time to time stray to Europe or
Asia. This, however, is by no means the only point of resemblance. Of
many genera, the so-called species found in the New World are
represented in the Old by forms so like them that often none but an
expert can distinguish them, and of such representative 'species'
about 80 might be enumerated" (Newton, _Dict. Birds_, p. 335).

Of the many attempts to subdivide the Nearctic subregion, the same
authority favours that of Dr S.F. Baird, who distinguishes between
_Canadian, Alleghanian, Middle_ or Missourian, _Californian_ and
_Alaskan_ provinces. Dr Hart Merriam takes the broad point of view
"that the whole of extratropical North America consists of but two
primary life regions, a _Boreal_ region, which is circumpolar, and a
_Sonoran_ or Mexican tableland region which is unique." The first of
these supports Newton's contention of the essential unity of the
Nearctic and Palaearctic areas. In any case the various Nearctic
subdivisions completely merge into each other, just as is to be
expected from the physical configuration and other bionomic conditions
of the Nort American continent.

The _Palaearctic Subregion_ is, broadly speaking, Europe and Asia,
with the exception of India and China. The propriety of comprehending
this enormous tract in one zoological "region" was first shown by Dr
P.L. Sclater, and as regards the distribution of most classes of
animals there have been few to doubt that it is an extremely natural
one. Not indeed altogether so homogeneous as the Nearctic area, it
presents, however, even at its extreme points, no very striking
difference between the bulk of its birds. Though Japan is far removed
from western Europe, and though a few generic forms and still fewer
families inhabit the one without also frequenting the other, yet there
is a most astonishing similarity in a large portion of their
respective birds. In some cases the closest examination has failed to
detect any distinction that may be called specific between the members
of their avifauna; but in most it is possible to discover just
sufficient difference to warrant a separation of the subjects.
Nevertheless, it is clear that in Japan we have, as it were, a
repetition of some of our most familiar species--the redbreast and the
hedge-sparrow, for example--slightly modified in plumage or otherwise,
so as to furnish instances of the most accurate representation, e.g.
_Cyanopica cooki_ of Portugal and Spain, and _C. cyana_ of Amoorland
and Japan.

Like the Nearctic the Palaearctic subregion seems to possess but one
single peculiar family of land birds, the _Panuridae_, represented by
the beautiful species known to Englishmen as the bearded tit-mouse,
_Panurus biarmicus_. The entire number of Palaearctic families are,
according to Newton, 67, and of the genera 323. Of these 128 are
common to the Nearctic subregion. Species of 51 more seem to occur as
true natives within the Ethiopian and Indian regions, and besides
these 18 appear to be common to the Ethiopian without being found in
the Indian, and no fewer than 71 to the Indian without occurring in
the Ethiopian. To compare the Palaearctic genera with those of the
Australian and Neotropical regions would be simply a waste of time,
for the points of resemblance are extremely few, and such as they are
they lead to nothing. It will therefore be seen from the above that
next to the Nearctic are the Palaearctic has a much greater affinity
to any other, a fact which might be expected from geographical
considerations.

Having shown this much we have next to deal with the peculiarities of
the vast Palaearctic subregion. At the lowest computation 37 genera
seem to be peculiar to it, though it is certain that species of
several are regularly wont to wander beyond its limits in winter
seeking a southern climate. Of the peculiar genera only a few examples
may be mentioned: _Eurynorhynchus_, the spoon-billed sandpiper of
Siberia; _Syrrhaptes_, the sandgrouse of central Asia; _Musicicapa_ of
Europe.

We distinguish between a _Siberian, Mongolian, Mediterranean_ and
_European province_, none of which can be well defined. The islands of
the Canaries, Madeira and the Azores belong to the Mediterranean
province, and offer some peculiarities of great interest. The Azores
have been monographed by F.D. Godman (_Nat. Hist. of the Azores or
Western Islands_, London, 1870). There is a general tendency among
these insular birds to vary more or less from their continental
representatives, and this is especially shown by the former having
always darker plumage and stronger bills and legs. In one instance the
variation is so excessive that it fully justifies the establishment of
a specific distinction. This is the case of the bullfinch of the more
western of these islands (_Pyrrhula murina_), the male of which,
instead of the ruddy breast of its well-known congener (_P.
vulgaris_), has that part of a sober mouse-colour. A similar sombre
hue distinguishes the peculiar chaffinch of the Canary Islands
(_Fringilla teydea_), but to these islands as well as the Azores and
Madeiras there belongs in common another chaffinch (_F. tintillon_)
which, though very nearly allied to that of Mauritania (_F.
spodogenia_) is perfectly recognizable, and not found elsewhere.
Madeira has also its peculiar golden-crested wren (_Regulus
maderensis_), and its peculiar pigeon (_Columba trocaz_), while two
allied forms of the latter (_C. laurivora_ and _C. bollii_) are found
only in the Canaries. Further on this subject we must not go; we can
only state that Godman has shown good reason for declaring that the
avifauna of all these islands is the effect of colonization extending
over a long period of years, and going on now.

PALAEOTROPICAL REGION.--Much can be said in favour of combining the
mostly tropical portion of the great mass of land of the Old World
(excluding, of course, Austrogaea or the Australian region) into one
region, for which Oscar Drude's well-chosen term "palaeotropical" has
been adopted (cf. Bronn's _Thierreich, System Part._ p. 296, 1893).
This region naturally comprises the African and Indian areas,
conformably to be called subregions.

Both subregions possess, besides others, the following characteristic
birds: Ratitae, viz. _Struthio_ in Africa and Arabia, fossil also in
the Sivalik Hills, and _Aepyornithidae_ in Madagascar; _Pittidae,
Bucerotinae_ and _Upupinae_, of which _Upupa_ itself in India,
Madagascar and Africa; _Coraciidae; Pycnonotidae_ or bulbuls;
_Trogonidae_, of which the Asiatic genera are the less specialized in
opposition to the Neotropical forms; _Vulturidae; Leptoptilus,
Anastomus_ and _Ciconia_ among the storks; _Pteroclidae; Treroninae_
among pigeons. Of other families which, however, extend their range
more or less far into the Australian realm, may be mentioned
_Otididae_, the bustards; _Meropidae_ or bee-eaters; _Muscicapidae_ or
flycatchers; _Sturnidae_ or starlings.

The _Ethiopian Subregion_ comprises the whole of Africa and
Madagascar, except the Barbary States, but including Arabia; in the
north-east the subregion melts into the Palaearctic between its limits
still farther to the eastwards, through Beluchistan and even beyond
the Indus.

So large a portion of the Ethiopian subregion lies between the tropics
that no surprise need be expressed at the richness of its fauna
relatively to that of the last two subregions we have considered.
Between fifty and sixty so-called families of land birds alone are
found within its limits, and of them at least nine are peculiar; the
typical genera of which are _Buphaga, Euryceros, Philepitta,
Musophaga, Irrisor, Leptosoma, Colius, Serpentarius, Struthio,
Aepyornis_. It is singular that only the first three of them belong to
the order _Passeriformes_, a proportion which is not maintained in any
other tropical region. The number of peculiar genera, besides those
just mentioned, is too great for them to be named here; some of the
most remarkable on the continent are: _Balaeniceps_, the whale-headed
heron; _Balaearica_, the crowned crane; _Podica_, finfoot; _Numida_
and allied genera of guinea fowls.

The natural division of the subregion is that into an African and a
Madagascar province. Subdivision of the continental portion is beset
with great difficulties, and none of the numerous attempts have proved
long-lived. The forest-clad basin of the Congo, with the coastal
districts of the bay of Guinea, seem to form one domain in opposition
to the rest.

The Malagasy province comprises, besides Madagascar, the Mascarene,
Comoro and Seyehelle islands. It may be safely deemed the most
peculiar area of the earth's surface, while from the richness and
multifariousness of its animal, and especially of its ornithic
population, New Zealand cannot be compared with it. In A. Grandidier's
magnificent _Histoire physique, naturelle et politique de Madagascar_,
vol. xii. (Paris, 1875-1884), are enumerated 238 species as belonging
to the island, of which 129 are peculiar to it, and among those are no
fewer than 35 peculiar genera. _Euryceros_ of the Oscines, and
_Philepitta_ of the Clamatores, are remarkable enough to form the
types of Passeriform families, and _Mesites_ half-way between Galli
and Gruiformes is of prime importance. The Passerine _Falculia_, with
its recently extinguished allies _Fregilupus_ and _Necropsar_ of the
Mascarenes; the Coraciine _Brachypteracias_, _Atelornis_ and
_Geobiastes_, are very abundant, while _Heliodilus_ is an owl
belonging to that subfamily which is otherwise represented only by the
widely-spread barn owl, _Strix flammea_. Lastly must be noted the
extinct tall Ratite species of _Aepyornis_ with its several fancy
genera. But, as Newton charmingly puts it (_Dict Birds_, p. 353), the
avifauna of Madagascar is not entirely composed of such singularities
as these. We have homely genera, even among the true _Passeres_,
occurring there--such as _Alauda, Acrocephalus, Motacilla_ and
_Pratincola_, while the _Cisticola madagascariensis_ is only
distinguishable from the well-known fan-tailed warbler, _C.
schoenicola_ of Europe, Africa and India by its rather darker
coloration. But there are also species, though not Passerine, which
are absolutely identical with those of Britain, the barn owl, common
quail, pigmy rail, and little grebe or dabchick, all of them common
and apparently resident in the island. Mauritius had the dodo (q.v.),
_Lophopsittacus_ and _Aphanapteryx_. Rodriguez had the solitaire,
_Necropsittacus_ and _Necropsar_. Bourbon or Reunion had _Fregilupus_.

Some of the Malagasy avifauna is certainly ancient, aboriginal, and
even points to India; other forms indicate clearly their African
origin; while, lastly, such strikingly characteristic Indo-African
birds as hornbills are unaccountably absent.

The _Oriental Subregion_ comprises all the countries and numerous
islands between the Palaearctic and Australian areas; it possesses
upwards of seventy families, of which, however, only one is peculiar,
but this family, the _Eurylaemidae_ or broadbills, is of great
importance since it represents all the _Subclamatores_. Of the many
characteristic birds may be mentioned _Pycnonotidae_ or bulbuls, of
which the _Phyllornithinae_ are peculiar, _Campephagidae_ or cuckoo
shrikes, _Dicruridae_ or drongos, _Nectariniidae_ or sunbirds;
pheasants, together with _Pavo_ and _Gallus_. Some of the similarities
to the Ethiopian and the great differences from the Australian
avifauna have already been pointed out. Naturally no line whatever can
be drawn between the Oriental and the Palaearctic subregions, and many
otherwise essentially Indo-Malayan families extend far into the
Australian realm, far across Wallace's line, whilst the reverse takes
place to a much more moderate extent. Certainly the Oriental area, in
spite of its considerable size, cannot possibly claim the standing of
a primary region. It is a continuation of the great Arctogaea into the
tropics.

Following H.J. Elwes we subdivide the whole subregion into a
Himalo-Chinese, Indian and Malayan province. These divisions had the
approval of W.T. Blanford, who proposed the terms Cis-and
Trans-gangetic for the two first. The Himalo-Chinese or Trans-gangetic
province shows the characteristics of its avifauna also far away to
the eastward in Formosa, Hainan and Cochin China, and again in a
lesser degree to the southward in the mountains of Malacca and
Sumatra. Indo-China is especially rich in _Eurylaemidae_, China proper
and the Himalayas in pheasants.

The Indian or Cisgangetic province is the least rich of the three so
far as peculiar genera are concerned.

The Malayan province comprising the Malay islands, besides the Malay
peninsula, and the very remarkable Philippines, possess an
extraordinary number of peculiar and interesting genera.

The influence of the Australian realm is indicated by a Megapode in
Celebes, another in Borneo and Labuan, and a third in the Nicobar
islands (which, however, like the Andamans, belong to the Indian
province), but there are no cockatoos, these keeping strictly to the
other side of Wallace's line, whence we started on this survey of the
world's avifauna.

D. CLASSIFICATION OF BIRDS

Fuerbringer's great work, published in the year 1888 by the _Natura Artis Magistra_ Society of Amsterdam, enabled Gadow not only to continue for the next five years the same lines of morphological research, but also further to investigate those questions which were still left in abeyance or seemed to require renewed study. The resulting "classification is based on the examination, mostly autoptic, of a far greater number of characters than any that had preceded it; moreover, they were chosen in a different way, discernment being exercised in sifting and weighing them, so as to determine, so far as possible, the relative value of each, according as that value may vary in different groups, and not to produce a mere mechanical 'key' after the fashion become of late years so common" (Newton's _Dictionary of Birds_, Introduction, p. 103). It is not the quantity but the quality of the anatomical and bionomic characters which determines their taxonomic value, and a few fundamental characters are better indications of the affinities of given groups of birds than a great number of agreements if these can be shown to be cases of isomorphism or heterophyletic, convergent analogy. Nature possesses three great educational or developmental schools--terrestrial, aquatic and aerial life. Each of these affords animal, vegetable or mixed diet. Animal diet implies the greatest variety with regard to locality and the modes of procuring the food. Each of these schools impresses its pupils, in the case of the birds, with its own stamp, but there are many combinations, since in the course of phyletic development many a group of birds has exchanged one school for another. Originally terrestrial groups have taken to an entirely aquatic life, and _vice versa_; others, originally endowed with the power of flight, have become, or are transforming themselves into, absolutely cursorial forms; some members of one group live entirely on seeds, while others have become fierce fishers, and so forth. Only by the most careful inquiry into their history can their relationship or pedigree be unravelled. A statement may now be given of Gadow's classification of birds, in which the extinct forms have been intercalated so far as possible. The few characters assigned to the various groups are sufficiently diagnostic when taken together, although they are not always those upon which the classification has been established:--

CLASS AVES

I. Sub-class ARCHAEORNITHES.--The three fingers and their metacarpals remain separate, each with a claw. Well-developed remiges. Both jaws with alveolar teeth. Amphicoelous. Caudal vertebrae more than thirteen, without a pygostyle, but with about twelve pairs of rectrices. _Archaeopteryx, A. lithographica, s. macroura_, two specimens from the upper Oolite of Solenhofen, Bavaria.

II. Sub-class NEORNITHES.--Metacarpals fused. Second finger the longest. Not more than thirteen caudal vertebrae.

I. Division RATITAE.--Terrestrial, flightless. Without sternal keel. Quadrate bone with single proximal knob. Without pygostyle. Coracoid and scapula fused. Compound rhamphotheca. Adult without apteria. With copulatory organ. A collective polyphyletic or heterogeneous group, originally cosmopolitan; with certainty existing since the Miocene.

1. Order Struthiones.--With pubic symphysis. Two toes only, third and
fourth. _Struthio_, ostrich, Pliocene of Samos and of north-west
India, now Africa and Arabia.

2. Order Rheae.--With long ischiadic symphysis. Three toes.
_Mesembriornis_, Miocene or Pliocene of Argentina. Rhea, South
America.

3. Order Casuarii.--Three toes. Aftershaft as long as the other half.
_Casuarius_ and _Dromaeus_, Australian. _Hypselornis_, Pliocene of
Sivalik Hills.

4. Order Apteryges.--Four toes. Bill long and slender. _Apteryx_, New
Zealand.

5. Order Dinornithes.--Three or four toes. Bill short. Anterior limbs
extremely reduced. _Dinornis_, numerous species, recently extinct, New
Zealand.

6. Order Aepyornithes.--_Aepyornis_, recently extinct, Madagascar.

To the Ratitae belong possibly also the imperfectly known _Diatryma_,
Eocene of New Mexico, _Gastornis_ and _Dasornis_, Eocene of Europe,
_Genyornis_, Pleistocene of Australia.

II. Division ODONTOLCAE.--Marine, flightless, without sternal keel. Upper and lower jaws with teeth in furrows. Cretaceous epoch. _Enaliornis_, England, vertebrae chiefly biconcave; _Hesperornis_, North America, vertebrae heterocoelous.

III. Division CARINATAE.--With keeled sternum.

1. Order Ichthyornithes.--Power of flight well developed. Vertebrae
still amphicoelous. With small pygostyle. Incisura ischiadica. With
alveolar teeth. Cretaceous of Kansas. _Ichthyornis, Apatornis_.

2. Order Colymbiformes.--Plantigrade, nidifugous, aquatic. All toes
webbed, fourth largest, hallux short; metatarsus laterally compressed;
tibia with high, pyramidal crest. Bill straight, pointed, with simple
sheath.

Sub-order 1. COLYMBI, Divers. Front toes completely webbed.
Holarctic. _Colymbus_.

Sub-order 2. PODICIPEDES, Grebes. Toes lobated. Cosmopolitan.

3. Order Sphenisciformes.--Nidicolous, marine. Flightless, wings
transformed into rowing paddles. SPHENISCI, penguins. Antarctic and
southern temperate coasts. Since the Eocene.

4. Order Procellariiformes.--Well flying, pelagic, nidicolous. Hallux
absent or vestigial. Rhamphotheca compound. Cosmopolitan. TUBINARES,
petrels and albatrosses.

5. Order Ciconiiformes.--Swimmers or waders. Desmognathous, without
basipterygoid processes; with one pair of sterno-tracheal muscles.

Sub-order 1. STEGANOPODES.--Well flying, aquatic, nidicolous; with
all the four toes webbed together. Rhamphotheca compound;
cosmopolitan. _Phaethon_, tropic-bird; _Sula_, gannet;
_Phalacrocorax_, cormorant and _Plotus_, snake-bird; _Fregata_,
frigate-bird; Pelecanus. Here also _Pelagornis_, Miocene of France;
_Argillornis_ and probably _Odontopteryx_ from the London Clay.

Sub-order 2. ARDEAE.--Piscivorous, nidicolous, waders; with
complicated hypotarsus and with long cervical apteria. _Ardeidae_,
cosmopolitan; including _Cancroma_, Neotropical, _Balaeniceps,
Scopidae_, Ethiopian. _Proherodius_, Eocene of England.

Sub-order 3. CICONIAE.--Zoophagous, nidicolous, waders; with simple
hypotarsus and without cervical apteria. Cosmopolitan. _Ciconiidae_,
storks. _Ibidae_, ibises and spoonbills. _Propelargus_, Oligocene.

Sub-order 4. PHOENICOPTERI.--Flamingos. Nidifugous, waders; with
simple hypotarsus and without cervical apteria. Front toes
completely webbed; hallux very short or absent; feed chiefly on
small aquatic invertebrates. _Phoenicopterus_, cosmopolitan.
Oligocene _Elornis_ and, allied, _Palaelodus_.

6. Order Anseriformes.--Desmognathous, nidifugous; with two pairs of
sterno-tracheal muscles, with complete basipterygoid processes and
with a penis.

Sub-order 1. PALAMEDEAE.--Screamers. Ribs without uncinate
processes. Hypotarsus simple. Neotropical. _Chauna, Palamedea_.

Sub-order 2. ANSERES.--Family _Anatidae_. Hypotarsus complex.
_Anser, Anas, Cygnus_, since Miocene. _Cnemiornis_, Pleistocene, New
Zealand, flightless.

7. Order Falconiformes.--Birds of prey. Carnivorous, desmognathous,
nidicolous, without functional caeca. Terrestrial, aerial.

Sub-order 1. CATHARTAE.--American vultures. With nares perviae.
_Cathartes_, turkey buzzards, _Sarcorhamphus gryphus_, condor
_Gypagus papa_, king vulture.

Sub-order 2. ACCIPITRES.--With nares imperviae. _Serpentariidae_,
secretary-bird, Ethiopian; Miocene, France. _Vulturidae_, Old World
vultures, excluding Australia. _Falconidae_, cosmopolitan, since the
Eocene. _Harpagornis_, Pleistocene, New Zealand; _Lithornis_,
Eocene, England. _Pandionidae_, ospreys or fish hawks, cosmopolitan.

8. Order Tinamiformes.--Nidifugous, with incisura ischiadica, without
pygostyle. Herbivorous, terrestrial, neotropical. _Crypturi_,
tinamous.

9. Order Galliformes.--Schizognathous, herbivorous, terrestrial. With
ten functional remiges. With strong spinae sterni.

Sub-order 1. MESITES.--Without basipterygoid processes, and with
large spina interna. _Mesites_, Madagascar.

Sub-order 2. TURNICES.--Hemipodes or button-quails. Nidifugous;
vomer large; sternum without processus obliqui. Hallux absent or
vestigial. Old World. _Turnix, Pedionomus_.

Sub-order 3. GALLI.--With large spina communis, and with large
processus obliqui. Hallux functional. _Megapodiidae_, Australian
region. _Cracidae_, curassows and guans, neotropical. _Gallidae_,
cosmopolitan.

Sub-order 4. OPISTHOCOMI.--Arboreal, with long spina externa;
without basipterygoid processes. _Opisthocomus_ hoatzin, Guiana,
Venezuela and Amazon countries.

10. Order Gruiformes. Legs of the wading type. Without basipterygoid
processes. Without spina interna. Nidifugous. Essentially
Schizognathous. _Rallidae_, cosmopolitan, since Oligocene. _Rallus,
Fulica, Ocydromus, &c., Gallinula nesiotis_, Tristan d'Acunha,
flightless. _Notornis_, New Zealand, flightless, nearly extinct.
_Aptornis_, New Zealand, flightless, extinct. _Aphanapteryx_
(Mauritius) = _Erythromachus_ (Rodriguez) = _Diaphorapteryx_ (Chatham
Island), flightless and recently extinct. _Gypsornis_, upper Eocene,
France. _Gruidae_, cranes, cosmopolitan, allied _Phororhacos_,
Tertiary of Argentina. _Dicholophidae_, cariamas, neotropical.
_Otididae_, bustards, Old World. _Rhinochetidae_, kagus, New
Caledonia. _Eurypygidae_, sun-bittern, neotropical. _Heliornithidae_,
finfoots, tropical.

11. Order Charadriiformes.--Schizognathous. With eleven remiges, of
which the terminal very short. Aquinto-cubital. Spinae sterni short,
separate.

Sub-order 1. LIMICOLAE.--Nidifugous, without spina interna sterni.
Hypotarsus complicated. _Charadriidae_, plovers. _Chionididae_,
sheath-bill. _Glareolidae_, wading swallows and coursers.
_Thinocorythidae_, seed-snipes. _Oedicnemididae_, thick-knees.
_Parridae_.

Sub-order 2. LARI.--Aquatic, vomer complete. Without basipterygoid
processes. Front toes webbed; hallux small or absent. Large
supraorbital glands. Since Miocene. _Laridae_, gulls, cosmopolitan.
_Alcidae_, auks, northern half of periarctic region.

Sub-order 3. PTEROCLES.--Sand-grouse. Nidifugous. Vomer vestigial.
With large crop and caeca. Hallux vestigial or absent since
Oligocene. Africa to India, and Siberia. _Pterocles_ and
_Syrrhaptes_.

Sub-order 4. COLUMBAE.--Pigeons. Nidicolous. Vomer vestigial. With
large crop, vestigial caeca. _Columbidae_, cosmopolitan, since
Miocene. _Dididae_, flightless, recently extinct. _Didus_, dodo,
Mauritius. _Pezophaps_, solitaire, Rodriguez.

12. Order Cuculiformes.--Desmognathous, nidicolous; zygodactylous, or
with the outer toe reversible.

Sub-order 1. CUCULI.--Cuckoos. Quinto-cubital. _Cuculidae_,
cosmopolitan. _Musophagidae_, plantain-eaters and touracos,
Ethiopian since Miocene.

Sub-order 2. PSITTACI.--Parrots. Zygodactylous; aquinto-cubital.
Cosmopolitan, chiefly tropical. _Trichoglossidae_, lories,
Austro-Malayan. _Nestor_, New Zealand. _Cyclopsittacus, Eos,
Lorius_, &c. _Psittacidae_, tongue smooth, incl. _Stringops_.

13. Order Coraciiformes.--Nidicolous. Nares imperviae, holorhinal.
Downs restricted to the apteria or absent. Thirteen to fifteen
cervical vertebrae. Mostly desmognathous. Deep plantar tendons
connected with each other.

Sub-order 1. CORACIAE.--Either (1) with long spina externa sterni,
_Coraciidae_, rollers, Old World. _Momotidae_, neotropical, motmots
and todies. _Alcedinidae_, kingfishers, cosmopolitan or (2) with
long spina communis. _Meropidae_, bee-eaters, Old World. _Upupidae,
Upupinae_, hoopoes: palaearctic and palaeotropical. _Bucerotinae_,
hornbills, palaeotropical; _Irrisorinae_, woodhoopoes, Ethiopian.

Sub-order 2. STRIGES.--Owls. Outer toe reversible. Schizognathous.
Long caeca. Flexor tendons normal. Hypotarsus simple. Cosmopolitan.

Sub-order. 3. CAPRIMULGI.--Nightjars. Nocturnal. With gaping mouth.
Ten remiges and ten rectrices. Spinae sterni vestigial. Caeca
functional. _Steatornithidae, Steatornis_, oil-bird or guacharo,
South America. _Podargidae_, Australasian, _Caprimulgidae_,
cosmopolitan.

Sub-order 4. CYPSELI.--Tenth terminal remex the longest. With short
spinae sterni. Without caeca. _Cypselidae_, swifts, cosmopolitan.
_Trochilidae_, humming-birds, American.

Sub-order 5. COLII.--Mouse-birds. First and fourth toes reversible.
Ethiopian.

Sub-order 6. TROGONES.--Trogons. Heterodactyle, first and second
toes directed forwards, third and fourth backwards. Tropical.
_Trogon gallicus_, Miocene of France.

Sub-order 7. PICI.--Zygodactylous. Tendon of the flexor hallucis
longus muscle sending a strong vinculum to that of the flexor
profundus muscle, the tendon of which goes to the third toe only.
_Galbulidae_, puff-birds and jacamars, neotropical. _Capitonidae_,
barbets, tropical. _Rhamphastidae_, toucans, neotropical. _Picidae_,
woodpeckers, cosmopolitan, excepting Madagascar and Australian
region.

14. Order Passeriformes.--Nidicolous. Aegithognathous, without
basipterygoid processes. Spina externa sterni large, spina interna
absent. Quinto-cubital, toes normal. Apparently since the upper
Eocene.

Sub-order 1. PASSERES ANISOMYODAE.--Syrinx muscles entirely lateral
or attached to the dorsal or ventral corners of the bronchial
semi-rings, (1) _Subclamatores_. Deep plantar tendons connected by a
vinculum. _Eurylaemidae_, broadbills, Indian and Indo-Malayan. (2)
_Clamatores_. Deep flexor tendons not connected. _Pittidae_,
palaeotropical. _Xenicidae_, New Zealand. _Tyrannidae_, American,
_Formicariidae_, _Pteroptochidae_, neotropical.

Sub-order 2. PASSERES DIACROMYODAE.--Syrinx muscles of either side
attached to the dorsal and ventral corners of the rings. Hallux
strong, with a large claw, (1) _Suboscines_ with _Menura_,
lyre-bird, and _Atrichia_, scrub-bird, in Australia. (2) _Oscines_,
the true singing-birds, with more than 5000 recent species, are
mostly divided into some thirty "families," few of which can be
defined.

The fourteen orders of the Carinatae are further congregated into four
"Legions":--

I. COLYMBOMORPHAE = Ichthyornithes + Colymbiformes + Sphenisciformes +
Procellariiformes.

II. PELARGOMORPHAE = Ciconiiformes + Anseriformes + Falconiformes.

III. ALECTOROMORPHAE = Tinamiformes + Galliformes + Gruiformes +
Charadriiformes.

IV. CORACIOMORPHAE = Cuculiformes + Coraciiformes + Passeriformes.

These four legions are again combined into two "Brigades," the first
of which comprises the first and second legions, while the second
brigade contains the third and fourth legions.

Thus the whole classification becomes a rounded-off phylogenetic
system, which, at least in its broad outlines, seems to approach the
natural system, the ideal goal of the scientific ornithologist. The
main branches of the resultant "tree" may be rendered as follows:--

CORACIOMORPHAE
+
ODONTOLCAE..COLYMBO + PELARGO- ALECTOROMORPHAE..RATITAE
MORPHAE MORPHAE
\----+----/ /
\----------+---------/
|
NEORNITHES

The Odontolcae seem to be an early specialized offshoot of the Colymbo
Pelargomorphous brigade, while the Ratitae represent a number of side
branches of early Alectoromorphae. The Ratitae branched off, probably
during the Eocene period, from that still indifferent stock which gave
rise to the Tinami + Galli + Gruiformes, when the members of this
stock were still in possession of those archaic characters which
distinguish Ratitae from Carinatae. It follows that new groups of
Ratitae can no longer be developed since there are no Carinatae living
which still retain so many low characters, e.g. configuration of the
palate, precoracoid, pelvis, intestinal convolutions, copulatory
organ, &c. Loss of the keel is co-ordinated with the power of using
the forelimbs for locomotion; although a "Ratite" character, it is not
sufficient to turn a _Notornis, Cnemiornis_ or _Stringops_, not even a
_Phororhacos_ into a member of the Ratitae.

Another branch of the Alectoromorphae, in particular of the
Galliformes, when these were still scarcely separated from the
Gruiformes, especially rail-like birds, leads through Opisthocomi to
the Cuculiformes. These are, again in an ascending direction,
connected with the Coraciiformes, out of which have arisen the
Passeriformes, and these have blossomed into the Oscines, which, as
the apotheosis of bird life, have conquered the whole inhabitable
world. (H. F. G.)

FOOTNOTES:

[1] Treviranus, _Biologie oder Philosophie der lebenden Natur_, vol.
ii. cap. 4, Sec. 2 (Goettingen, 1803).

[2] F. Tiedemann, _Anatomie und Naturgeschichte der Voegel_, vol. ii
Sec.Sec. 127-255 (Heidelberg, 1814).

[3] L.K. Schmarda, _Die geographische Verbreitung der Thiere_ (Wien,
1853).

[4] P.L. Sclater on the general geographical distribution of the
members of the class "Aves," 2. _Linn. Soc._ ii. pp. 130-145, 1858.

[5] A.R. Wallace, _The Geographical Distribution of Animals, with a
study of the Relations of Living and Extinct Faunas as elucidating
the Past Changes of the Earth's Surface_, 2 vols. (London, 1876).

[6] T.H. Huxley, "On the Classification and Distribution of the
Alectoromorphae," _P.Z.S._, 1868, pp. 313-319.

[7] The following old-fashioned rough computation may serve as an
indication of the relative size of the orders and suborders of recent
birds:--

Ratitae 20 Charadriiformes 650 (incl. Columbae
Colymbiformes 20 350)
Sphenisciformes 15 Cuculiformes 600 (incl. Psittaci
Procellariiformes 90 400)
Ciconiiformes 150 Coraciiformes 1600 (incl. Trochili
Anseriformes 150 and Pici)
Falconiformes 360 Passeres Clamatores 1000
Tinamiformes 40 Passeres Oscines 5000
Galliformes 370 ------
Gruiformes 250 Total about 10,300 species

BIRD-LOUSE, any small flat degenerate wingless neuropterous insect of the group Mallophaga, parasitic upon birds and mammals and feeding upon dermal excretions or upon the softer parts of hair and feathers. The term "biting-lice" is sometimes given to these parasites, in allusion to the mandibulate character of their mouth-parts, which serves to distinguish them at once from the true lice of the order Rhynchota in which the jaws are haustellate.

BIRD'S-EYE, a name applied to various small bright flowers, especially those which have a small spot or "eye" in the centre. The primula is thus spoken of, on account of its yellow centre, also the adonis, or "pheasant's eye," and the blue veronica, or germander speedwell. The word is also applied to a sort of tobacco, in which the stalks (of a mottled colour) are cut up together with the leaves. From a similar sense comes the phrase "bird's-eye maple," a speckled variety of maple-wood, or the "bird's-eye handkerchief" mentioned in Thackeray's novels.

BIRDSNESTING, a general term for the pursuit of collecting and preserving birds' eggs, with or without the nests themselves. The nests and eggs of wild birds are nowadays protected by local laws almost everywhere in both Great Britain and the United States. By law they may be taken for scientific purposes only, by special licence. In order not to interfere seriously with breeding it is customary to take but one egg from a nest, and, if the nest itself be taken, to wait until the young birds have left it. Every egg, unless "hard-set," should be blown as soon as removed from the nest. This is done by opening a small hole in its side by means of a drill with a conical head, manufactured for the purpose, a minute hole for the insertion of the drill-head having first been made in the shell with a needle, which is then used to stir up the contents, so that they shall flow easily. A blow-pipe with a curved mouth is then inserted, the egg is held hole downwards, and the contents blown out. The old-fashioned method of making two holes in the egg is thus superseded. Should the egg be "hard-set" a somewhat larger hole is made and its edges reinforced with layers of paper pasted round them. Minute forceps are then introduced and the embryo cut into pieces small enough to pass through the hole. The inside of the egg is then rinsed out with clean water, and also before being placed in the cabinet, with a solution of corrosive sublimate, which prevents decay and consequent discoloration of the inner membrane. Finally the egg is placed with the hole downwards upon a sheet of white blotting-paper to dry. The authentication of the eggs is the most important duty of an egg-collector, next to identifying the specimens. According to some the best method is to mark with a fine pen on the egg itself the variety, scientific name, locality of nest, date of taking and the initials of the collector, as well as a reference to his note-book or catalogue. Others advocate keeping the authentication separate with only a numbered reference on the egg itself. Eggs should not be transported in bran or sawdust, but in strong wool-lined boxes. The best cabinets are fitted with drawers, pulled out to inspect the eggs, but at other times closed to preserve them from the light, which is injurious to their delicate colouring. When an entire nest is taken it should be disinfected with hyposulphite of soda or insect-powder.

See _Birdnesting and Bird-Skinning_, by E. Newman (London, 1888);
_The Young Collector's Handbook of British Birds' Nests and Eggs_, by
W.H. Bath (London, 1888); _Birds' Nests, Eggs and Egg-Collecting_, by
R. Kearton (London, 1890); _British Birds' Eggs and Nests_, by J.C.
Atkinson (London, 1898); _Nests and Eggs of North American Birds_, by
Ernest Ingersoll (1880-1881).