Lark (family Alaudidae)

Height

Larks are small to medium-sized ground-dwelling birds. Their body length ranges from 10 to 23 centimeters. Among the smallest larks are the white-fronted lark, which occurs from Africa to northwestern India, and in which adult females occasionally have a body length of only 10 centimetres, and the harlequin lark, which is native to East Africa and is 11.5 centimetres long. The smallest Central European lark is the woodlark, with a body length of about 15 centimetres. The crested lark, on the other hand, reaches a length of 17 to 19 centimetres.

The two largest lark species are the desert skylark, which occurs from the Cape Verde Islands to western India, and the marsh lark, a character species of the Tibetan highlands. According to these differences in body size, larks weigh between 11 and 53 grams.

Camouflage plumage

Larks are mostly inconspicuous earth-colored and in most species not colored differently according to sexes. The most contrasting drawings among the larks are found in the horned lark and the horned lark, which are often called the most beautiful lark species because of their black and white facial masks.

On the upper side of the body, larks are coloured from sandy to greyish to brownish and often have a dense streaking, which is created by differently coloured feather seams, dark feather centres and mostly dark shaft streaks. The underside of the body is lighter, ranging from white to cream to light rust tones. The underside of the body also has streaking in most species, but it is often limited to the breast and head areas. In general, the barring is less pronounced in species whose habitat has little vegetation than in species that occur in grass-dominated habitats.

Larks are usually well camouflaged by their plumage colouring. In many species, the upper side of the plumage matches the ground colour of their range. This is particularly pronounced in the Mirafra species, which occur predominantly in Africa, but the Rock Lark, which occurs in numerous subspecies from North Africa through the Near East to Central Asia, also has plumage that corresponds to the respective ground colour to a particular degree. The plumage colouring of the individual subspecies of the Rock Lark varies accordingly depending on the habitat from light sandy tones to dark slate-grey in the case of the subspecies Ammomanes desserti annae, which occurs in Jordan on black lava desert. The good camouflage provided by the plumage, which is typical of most lark species, is further enhanced by certain behaviours in the face of danger: they either remain motionless and can then hardly be detected from the surroundings of their habitat, or seek shelter in the low vegetation. Camouflage can be so pronounced that the presence of larks is often only noticed by the song of the males.

The differences in the plumage of the individual species are often only slight: in some cases the colouration of the tail feathers is an essential distinguishing feature. Some species can only be identified by their song or the behaviour of the male during or after the song flight.

Young birds have a slightly more contrasting plumage compared to adults. The feather ends are often lighter or the feather seams are broader.

Sexual dimorphism

In most species of larks there is no or very little sexual dimorphism in plumage. Females are typically slightly duller in colour and slightly smaller and lighter. Exceptions among the larks include the knob-billed lark, thrush lark, and red-rumped lark, as well as several species of the genus Eremopterix. In the Knacker's Lark, the female is slightly paler in overall coloration and the markings on the underside of the body are slightly browner. The same is true for the Drosper's Lark. In the Red-rumped Lark, the female appears more reddish on the upper side of the body because the reddish-brown fringes of the hand wings are more pronounced in females.

In the vast majority of Eremopterix species the difference is much more pronounced than in the species mentioned above. Apart from the Hoval lark, the males of this genus have black facial markings, which are absent in the inconspicuous brownish females.

Beak

The beak shape of larks ranges from a grosbeak-like conical beak in the Knacker's Lark to the long and thin beaks of the Runner Larks. Most species have a slender bill, with the bill length usually shorter than the head length. The species with more powerful bills, such as those of the Calandra Lark or Mirafra species, are predominantly seed eaters. Species with medium-sized bills, as is typical of the crested lark or skylark, feed on small seeds and insects. Species with very slender bills, as is the case with the woodlark or horned lark, feed mainly on insects and take seeds only in winter. The nostrils are completely exposed in the species of the genus Mirafra, Pinarocorys, Certhilauda and Alaemon; in the other genera they are covered with small feathers.

Wings and tail

The wings of larks are relatively long and wide. They have 10 hand wings, and unlike most songbirds, which usually have nine arm wings, at least 10 arm wings. The species of the genus Certhilauda even have 11 arm wings.

The tail is short to medium length and ends straight in most species. They have a total of 12 tail feathers. In many species the middle pair of control feathers is coloured differently from the rest of the tail feathers.

Locomotion

On the ground, larks do not hop, but they run - that is, they put their legs forward alternately, without both feet leaving the ground at the same time. They reach speeds of up to 7 km/h and move faster than any other European songbird species. As with all songbirds, three toes point forward and one backward. The elongated and powerful hind toe in larks is an adaptation to their ground-dwelling lifestyle. The shape of the hind claw - curved or straight - as well as the length compared to the hind toe is one of the characteristics by which species are differentiated, among others.

When flying, the legs are pulled chestwards, so that they disappear in the plumage and the back of the leg shows to the ground. The strongly curved front toes and the claw of the hind toe are directed tailwards. Only when singing do some species let their legs hang down. One of the special characteristics of the larks is that the back of the barrel is divided into four-sided shields.

The flight style of larks varies greatly. Compared with the peepers, with which the larks share many features in the habitus, their flight is heavier, noisier and broader-winged.

Features

The song of many lark species is very melodious and is performed with great vehemence. Quite a few species are so-called "mockers" and pick up the voices of other bird species in their environment. The mockingbird, for example, melodically combines the voices of several bird species. So far, the mimicry of 57 other bird species from 20 different genera has been identified in this species. Like the mockingbird, the sabot lark, which is native to Africa, even imitates the calls of 60 other bird species.

Larks also imitate sounds of their environment: There is a well-known case of a crested lark that imitated a shepherd's whistles, which he used to communicate commands to his dogs. The lark imitated these whistles so perfectly that the dogs followed it. Other larks in the neighbourhood also included these calls in their repertoire.

Singing Flight

Often the song is performed by the male in flight. Typical for larks is a steep ascent with fast wing beats, during which the song is sung without interruption. Some lark species reach considerable heights: For example, the Ogaden's lark, which is found in East Africa, soars up to 100 metres during its song flight. The hawker lark, native to southern West Africa, occasionally reaches heights of up to 200 metres during its song flight. Other lark species, on the other hand, remain much lower: for example, the chirping lark, which is found in southern Africa, rises only two metres before it glides back to the ground with its wings set steeply and singing.

When the singing male has reached a sufficient altitude, he often goes into a circling singing flight, in which he remains at the same altitude without changing his wing beat or song, circling slowly over his territory. There are species in which this singing flight lasts up to 25 minutes. After that, the larks slowly glide back down with their wings often motionless and completely outstretched. The song is still continued on that occasion. Other species drop more abruptly and steeply from their singing height, intercepting the flight just above the ground. The grey-crowned lark, showing a song flight at first reminiscent of a skylark, drops abruptly from about 30 metres, but does not land, instead showing a series of aerial leaps. Up to 40 aerial jumps were counted over a distance of 100 metres. Only then does it land on a stone or a clod of earth.

Many species additionally have a ground song, which is performed from perches. In some species, such as the Pale-breasted Lark, the flight song is rare. Instead, it is almost always performed from the highest branch of a tree or bush.

Some larks perform its chant also in moonlit nights.

Instrumental sound

Some species from the genera Mirafra and Chersophilus produce rattling and clattering instrumental sounds in addition to their song during this flight by flapping their wings together over their backs. In the case of the grass and tree skylark, these instrumental sounds are so typical of their singing flight that it even gives them their name.