Page:EB1911 - Volume 16.djvu/238

Rh in the season, their produce on the average may be set down as at least quadrupling the original stock—the eggs in each nest varying from five to three. Young larks leave their birthplace as soon as they can shift for themselves. When the stubbles are cleared, old and young congregate in flocks.

In Great Britain in the autumn they give place to others coming from more northerly districts, and then as winter succeeds in great part vanish, leaving but a tithe of the numbers previously present. On the approach of severe weather great flocks arrive from the continent of Europe. On the east coast of both Scotland and England this immigration has been noticed as occurring in a constant stream for as many as three days in succession. Farther inland the birds are observed “in numbers simply incalculable,” and “in countless hundreds.” In these migrations enormous numbers are netted for the markets, but the rate of reproduction is so rapid, and the conditions of life so favourable in Europe that there is no reason to fear any serious diminution in the numbers of the species.

The skylark’s range extends across the Old World from the Faeroe to the Kurile Islands. In winter it occurs in North China, Nepal, the Punjab, Persia, Palestine, Lower Egypt and Barbary. It sometimes strays to Madeira, and has been killed in Bermuda, though its unassisted appearance there is doubtful. It has been successfully introduced on Long Island, in the state of New York, into Hawaii and into New Zealand—in which latter it has become as troublesome a denizen as are some other subjects upon which acclimatization societies have exercised their activity.

Allied to the skylark a considerable number of species have been described, of which perhaps a dozen may be deemed valid, besides a supposed local race, Alauda agrestis, the difference between which and the normal bird is shown in the annexed woodcut (fig. 1), kindly lent to this work by H. E. Dresser, in whose Birds of Europe it is described at length. These are found in various parts of Africa and Asia.

The woodlark, Lullula arborea, is a much more local and, therefore, a far less numerous bird than the skylark, from which it may be easily distinguished by its finer bill, shorter tail, more spotted breast and light superciliary stripe. Though not actually inhabiting woods, as its common name might imply, it is seldom found far from trees. Its song wants the variety and power of the skylark’s, but has a resonant sweetness peculiarly its own. The bird, however, requires much care in captivity. It has by no means so wide a range as the skylark, and perhaps the most eastern locality recorded for it is Erzerum, while its appearance in Egypt and even in Algeria must be accounted rare.

Not far removed from the foregoing is a group of larks characterized by a larger crest, a stronger and more curved bill, a rufous lining to the wings, and some other minor features. This group has been generally termed Galerita, and has for its type the crested lark, the Alauda cristata of Linnaeus, a bird common enough in parts of France and some other countries of the European continent, and one which has been obtained several times in the British Islands. Many of the birds of this group frequent the borders if not the interior of deserts, and such as do so exhibit a more or less pale coloration, whereby they are assimilated in hue to that of their haunts. The same characteristic may be observed in several other groups—especially those known as belonging to the genera Calandrella, Ammomanes and Certhilauda, some species of which are of a light sandy or cream colour. The genus last named is of very peculiar appearance, presenting in some respects an extraordinary resemblance to the hoopoes, so much so that the first specimen described was referred to the genus Upupa, and named U. alaudipes. The resemblance, however, is merely one of analogy.

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. 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 finchlike; 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 Motacillidae and almost in certain Limicolae. The most constant character indeed of the Alaudidae 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.

In the Old World larks are found in most parts of the