Page:Encyclopædia Britannica, Ninth Edition, v. 14.djvu/334

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called "mimicry," though that may ultimately prove to be the case.

There is, however, abundant evidence of the susceptibility of the Alaudine structure to modification from external circumstances, – in other words, of its plasticity; and perhaps no homogeneous group of Passeres could be found which better displays the working of "Natural Selection." This fact was recognized many years ago, and ere "Darwinism" was founded as a creed, by one whose knowledge of the Alaudidæ was based on the safe ground of extensive personal observation, and by one who cannot be suspected of any prejudice in favour of new-fangled notions. The remarks made by Canon Tristram (Ibis, 1859, pp. 429-433) deserve all attention, going, as they go, to the root of the matter, and nothing but the exigencies of space precludes their reproduction here. A monograph of the Family executed by a competent ornithologist from an evolutionary point of view could not fail to be a weapon of force in the hands of all evolutionists. Almost every character that among Passerine birds is accounted most sure is in the Larks found subject to modification. The form of the bill varies in an extraordinary degree. In the Woodlark (fig. 2, A), already noticed, it is almost as slender as a Warbler's; in Ammomanes it is short; in Certhilauda (fig. 2, B) it is elongated and curved; in Pyrrhulauda and Melanocorypha (fig. 3, A) it is stout and Finch-like; while in Rhamphocorys (fig. 3, B) it is exaggerated to an extent that surpasses almost any Fringilline form, exceeding in its development that found in some members of the perplexing genus Paradoxornis, and even presenting a resemblance to the same feature in the far-distant Anastomus – the tomia of the maxilla not meeting those of the mandibula along their whole length, but leaving an open space between them. The hind claw, generally greatly elongated in Larks, is in Calandrella (fig. 4) and some other genera reduced to a very moderate size. The wings exhibit almost every modification, from the almost entire abortion of the first primary in the Skylark to its considerable development (fig. 5), and from tertials and scapulars of ordinary length to the extreme elongation found in the Motacillidæ and almost in certain Limicolæ. The most constant character indeed of the Alaudidæ would seem to be that afforded by the podotheca or covering of the tarsus, which is scutellate behind as well as in front, but a character easily overlooked.^[1]

Fig. 2. – A, Alauda arborea; B, Certhilauda. Fig. 3. – Melanocorypha calandra; B, Rhamphocorys clot-bey. Fig. 4. – Calandrella brachydactyla.

In the Old World Larks are found in most parts of the Palsearctic, Ethiopian, and Indian Regions; but only one genus, Mirafra, inhabits Australia, where it is represented by, so far as is ascertained, a single species, M. horsfieldi; and there is no true Lark indigenous to New Zealand. In the New World there is also only one genus, Otocorys,^[2] where it is represented by two species, one of which, found over near ly the whole of North America, is certainly not

Fig. 5. – A, Alauda arborea; B, Certhilauda; C, Melanocorypha calandra.

distinguishable from the Shore-Lark of Europe and Asia, O. alpestris; while the other, confined to the higher eleva tions of more southern latitudes, seems to be the relic of a former immigration (perhaps during a glacial period) of the northern form, which has through isolation come to be differentiated as O. chrysolæma (see BIRDS, vol. iii. p. 746). The Shore-Lark is in Europe a native of only the extreme north, but is very common near the shores of the Varanger Fjord, and likewise breeds on mountain-tops further south-west, though still well within the Arctic circle. The mellow tone of its call-note has obtained for it in Lapland a name signifying "Bell-bird," and the song of the cock is lively, though not very loud. The bird trustfully resorts to the neighbourhood of houses, and even enters the villages of East Finmark in search of its food. It produces at least two broods in the season, and towards autumn migrates to lower latitudes in large flocks. Of late years these have been observed almost every winter on the east coast of Great Britain, and the species instead of being regarded, as it once was, in the light of an accidental visitor to the United Kingdom, must now be deemed an almost regular visitor, though in very varying numbers. The observations on its habits made by Audubon in Labrador have long been known, and often reprinted.^[3] Other congeners of this bird are the O. penicillata of south-eastern Europe, Palestine, and Central Asia – to which are referred by Mr Dresser (B. Europe, iv. p. 401) several other forms origin ally described as distinct; but the specific validity of one of them, O. longirostris, has since been reasserted by Dr Scully (Ibis, 1881, p. 581) – as well as the O. bilopha of Arabia and Mauritania. All these birds, which have been termed Horned Larks, from the tuft of elongated black feathers growing on each side of the head, form a little group easily recognized by their peculiar coloration, which calls to mind some of the Ringed Plovers, Ægialitis (see KILLDEER, p. 76 of the present volume).

The name Lark is also frequently applied to many birds which do not belong to the Alaudidæ as now understood.

1 By assigning far too great an importance to this superficial character (in comparison with others), Sundevall (Tentamen, pp. 53-63) was induced to array the Larks, Hoopoes, and several other heterogeneous groups in one "Series," to which he applied the name of Scutelliplantares.

2 By American writers it is usually called Eremophila, but that name seems to be preoccupied in natural history.

3 The osteology of this bird is minutely described by Dr Shufeldt (Bull. U. S. Geol. Survey, vi. pp. 119-147).

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