Vertebrate Zoology: A Study Guide - T. A. Dauda 2014

Metazoa
Class Aves
Superorder Neognathae — Order Galliformes

The order Galliformes unites terrestrial and arboreal herbivorous birds ranging in size from small (quails) to large (wild turkeys). They have a stout build, a relatively short neck, and short, rounded wings. Their legs are moderately long and feature four toes with thick, long, and slightly curved claws adapted for scratching the soil. In many species, males are noticeably larger than females and differ in plumage coloration.

Fowl often gather in flocks, spending a significant amount of time on the ground, where they walk and run well. They take flight reluctantly with a noisy flutter of frequent wingbeats, usually flying low above the ground.

Most species are polygamous. Gallinaceous birds nest on the ground, laying clutches of 6 to 26 eggs. The female alone cares for the offspring. The chicks hatch covered in dense down, with open eyes, and within the very first hours of life are capable of running well, hiding, and feeding independently—making them typical precocial birds.

There are approximately 250 known species of Galliformes. They are predominantly resident or nomadic birds. Most hold game value, and many domestic breeds have been developed (Fig. 45). The order is subdivided into several clearly distinguishable families.

Phasianidae, or pheasants, are the most species-rich family among fowl. In all representatives, the tarsus lacks feathers and is armed with spurs in males. They are distributed across southern and temperate latitudes. The family includes the North American turkey—the ancestor of domestic turkeys, the helmeted guineafowl, the Indian peafowl, and wild Indian fowl, among which the red junglefowl is of the greatest importance as the ancestor of domestic chickens. In our country, Representatives of the Phasianidae include quails, which are the smallest (weighing 50-135 g) and the only migratory birds among the fowl; grey and rock partridges; snowcocks (the former species ranges all the way to the taiga, while the latter two inhabit the mountains of the Caucasus and Central Asia); and the common pheasant, found in the Caucasus, Central Asia, Kazakhstan, and certain other regions within dense forests, shrub thickets, and reed beds.

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Fig. 45 Chicken breeds:

1 — Leghorn rooster and hen; 2 — gamecock; 3 — Orlov rooster and hen.

Only 18 species of grouse (Tetraonidae) are known. Their tarsi are feathered to varying degrees, and spurs are absent. The nostrils are covered with dense feathers. In winter, a fringe of horny projections grows along the toes, allowing the birds to grip slippery branches. Distributed across northern and temperate latitudes, they are predominantly arboreal.

Partridges—including the grey, willow, and rock ptarmigans—are about the size of a pigeon and lead a largely terrestrial lifestyle. They feed on berries and seeds, while the grey partridge consumes large quantities of harmful insects (such as the sunn pest, owlet moth caterpillars, and loopers); to grind up coarse food, they swallow numerous pebbles. Partridges build their nests on the ground, typically laying clutches of 5 to 15 eggs. These birds are an important game species.

The black grouse is about the size of a domestic chicken, weighing 1.7 kg. The plumage of the male is black with a bluish sheen, while females are reddish-brown. The black grouse is widely distributed in forest and forest-steppe zones, primarily around forest edges, burnt-over areas, and clearings. In summer, it leads a terrestrial lifestyle, whereas in winter it roosts on the ground—more specifically, burrowing into the snow. The female builds a ground nest and lays 4 to 8 eggs. In summer, black grouse feed on green plant parts, berries, and insects, while in winter their diet shifts to buds, shoots, and catkins of birch and alder. They swallow numerous pebbles to aid in grinding coarse food. This bird is an important game species. The Caucasian grouse, which resembles the black grouse, is found in the mountains of the Caucasus. This species is rare and listed in the IUCN Red List.

Capercaillies are among the largest gallinaceous birds, with individual males reaching weights of up to 6.5 kg. The best known is the western capercaillie, ranging from our western borders to Transbaikalia. It takes off from the ground with difficulty and readily perches in trees. During the breeding season, males display and perform a mating song consisting of quiet "clicking" and "sharpening" sounds. For 4 to 8 seconds at the end of the song, the male temporarily becomes deaf. These birds nest on the ground, most commonly laying 6 to 8 eggs. Only the female incubates the eggs and tends to the chicks. The chicks feed on insects and their larvae, while adult birds in summer consume berries, leaves, plant seeds, and insects. In autumn, winter, and spring, the capercaillie's diet consists of pine, larch, and spruce needles, as well as birch buds. Swallowed pebbles assist in breaking down these coarse foods. In the forests of Eastern Siberia (east of Lake Baikal), the smaller black-billed capercaillie is found. In areas of high population density, capercaillies represent an important game resource.

The hazel grouse is a medium-sized bird, about 35 cm in length and weighing around 400 g. The plumage of both male and female is mottled, with the male having a black chin and throat, whereas the female's are light-colored. Ranging from our western borders to Kolyma and Sakhalin, this resident bird inhabits old, dense forests. During courtship displays, the male produces a high-pitched, melodious whistle. Females build nests on the ground and lay 6 to 15 eggs. Only the female incubates the clutch and cares for the brood. The chicks feed on insects and their larvae, green plant parts, seeds, and berries. Adults likewise feed on berries, seeds, plant leaves, and insects. In winter, they eat berries, buds, and catkins of birch, alder, and willow. Like black grouse, they roost in the snow during winter. The hazel grouse is one of the primary game bird species.