Physical characteristics

Larks range in size from the size of a finch to that of a thrush, i.e., 3.9-9.0 in (10-23 cm) and weight 0.4-2.6 oz (12-73 g). In some species males are larger and heavier than females. The plumage is usually inconspicuous, the upper-parts being heavily streaked or unmarked, with a general brownish to grayish color. The plumage is often adapted to the color of local soil so that many larks are remarkably camouflaged. Nonmigrating species with large breeding ranges extending over many habitats with different soil types tend to contain several subspecies that differ in color. The underparts are usually light and without any pattern. Several species have crown feathers which they can raise to a crest; most conspicuous is the crested lark (Galerida cristata) and its congenerics. In most species both sexes look very similar. Even both sexes

Four-day-old wood lark (Lullula arborea) chicks sit in their nest. (Photo by G. Synatzschke/OKAPIA. Photo Researchers, Inc. Reproduced by permission.)

of the horned lark (Eremophila alpestris) and Temminck's lark (E. bilopha) possess a contrasting colored pattern of breast and head, and they have tiny elongated feathers above their eyes that form conspicuous horns. However, the breeding plumage of the male black lark (Melanocorypha yeltoniensis) is entirely black. The males of the seven known sparrow-larks (Ere-mopterix) have black underparts and a species-specific black-and-white pattern on their head. Only the male black-eared sparrow-lark (E. australis) is totally black-headed; females of all these species are colored as larks in general.

Juveniles often have a spotted plumage, which distinguishes them from their parents. This is most conspicuous in the juveniles of horned larks and Temminck's larks, where the feather-horns of the adult plumage are also missing. Adult larks molt completely once per year after the breeding season. With the exception of Alaemon and Eremopterix, the juvenal plumage is replaced by the adult plumage immediately after the bird becomes fully fledged. This juvenal molt is very unusual among nontropical oscines.

In general, the nostrils are concealed with small tufts of feathers. They are clearly visible, however, in the case of Alae-mon, Certhilauda, Heteromirafra, Mirafra, and Pinarocorys.

The bills of larks are astonishingly diverse in shape, ranging from short, heavy, and conical to elongated, thin, and pointed. These differences reflect adaptations to a variety of food and feeding techniques. The thick-billed lark (Rampho-coris clotbey) stands out as an extreme; its bill is massive, short, and very deep, reminiscent of the bill of a grosbeak. This lark is, however, unique in having a toothlike projection on its lower mandible which fits into a notch in the upper mandible. The short bills of Calandrella and Eremopterix are less heavy, but similar to those of finches due to their conical shape. All these species feed mainly on seeds, but insects are more common in the diet of other larks. The horned lark has a short, pointed bill like some pipits; the same applies to the wood lark (Lullula arborea) and fawn-colored lark (Mirafra africanoides). Others like the red-winged lark (Mirafra hypermetra) or the crested lark have long and robust bills which are also used for digging. Dupont's lark (Chersophilus duponti), the greater hoopoe lark (Alaemon alaudipes), and the Cape long-billed lark (Certhilauda curvirostris) are characterized by elongated, slightly decurved, and slender bills. Some species are sexually dimorphic in respect to bill length; the male has a longer bill than the female.

Larks usually have short legs, but they are fairly long in Alaemon and Certhilauda. Larks have strong feet. The hind claw is much longer than the toes, especially in species living on soft soil. However, the hind claw is shorter in larks that live on hard ground or are fast runners such as Alaemon.

All lark nestlings have a characteristic brightly colored gape, with one black spot inside the tip of the upper and lower mandible. There are two black spots on the base of the tongue in Ammomanes, some Certhilauda, and Mirafra; and an additional third spot on the tip of the tongue in Alauda, Calan-drella, some Certhilauda, Eremophila, Galerida, and Lullula. After hatching, larks are covered with scanty down on their foreheads, napes, backs, shoulders, wings, and thighs.

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