It includes only one family - Alcidae, which unites about 20 species of seabirds that spend their whole lives on the high seas and are associated with land only during the breeding season. Weight 80 g - 1.2 kg. The shape of the beak is diverse: elongated conical, high, highly compressed laterally or short swollen. Legs are short, laid back. The front fingers are connected by a swimming membrane. Some species walk well, others travel awkwardly overland. The wings are short, narrow. The flight is fast, but not maneuverable. All species swim beautifully and dive to a depth of several tens of meters, move in the water, flapping their wings (underwater flight). The color of males and females is similar. Monogamy. Nests in colonies from several pairs to hundreds and thousands of pairs along rocky cliffs of the sea coasts of northern and temperate latitudes. Several species of purebred birds and gulls form large mixed colonies - bird markets. Large guillemots, dead end - Fralercula arciica in the Atlantic, hatchet - Lunda cirrhata, see Fig. 35, in the Pacific). Both partners incubate. Chicks are covered with thick and warm fluff, sighted. Parents feed them. Chayr chicks leave the cliffs and swim with their parents into the open sea at the age of three weeks, barely reaching the Uz mass of adults, but already fledged. Chicks of other species fly into the sea at the age of 4-6 weeks, reaching the size of adults. Food - small fish and a variety of marine invertebrates - is obtained only in water, swimming and diving.
Many species of waders, partly gulls and cleaners, are objects of hunting. In some areas where large colonies of grouse and gulls are still preserved, they are of commercial importance: they collect eggs - with properly organized fishing, some birds resume laying - and use the meat of adult birds. Seagulls and terns in the area of colonies and on migration destroy many insects in ponds and fields, including harmful and mouse-like rodents (large gulls, even ground squirrels). Many harmful invertebrates destroy sandpipers. The harm to fisheries in natural reservoirs is usually greatly exaggerated: gulls and anthropoids eat a lot of non-commercial weed fish (food competitors of valuable fish) and destroy invertebrates that eat caviar and fry. Eating sick and dead fish, gulls play the role of orderlies. In recent years, the deaths of seagulls and purebirds from water pollution by oil and various toxic industrial wastes have risen sharply.
Suborder Scuba Alcae
Chistikovye - truly seabirds living in the shelf and pelagic zones and associated with land only during the nesting period. In modern species, sizes vary from small (about 100 g) to medium (up to 1.3 kg). The extinct wingless loon, apparently, reached a weight of 5 kg.
They are perfectly adapted for swimming on the surface of the water with the help of legs and in the water column using wings ("underwater flight"). This left a definite imprint on the morphological features of the anthology. Most species are characterized by a slightly elongated spindle-shaped body, dense plumage, legs laid back, and short pointed wings. Paws are equipped with a swimming membrane. The back finger is reduced. The skull is schizognathic, schizorinal with through nostrils. In the developed supraorbital fossae there are large nasal glands. The nostrils are protected by a leathery valve. In adult birds, the basiperteroid articulations do not function. Cervical vertebrae 15. Thoracic vertebrae do not fuse into the sternum. The sternum and pelvis are narrow and elongated. The pectoral muscles are well developed. The skeleton of the wing is flattened, the forearm is shorter than the brush. The weight load on the wing is much greater than that of gulls. The hind limbs are relatively short. Onshore, purebreds usually rely on the entire metatarsus and move awkwardly. In general, the skeleton is slightly pneumatized. Pterillia and apterias are completely covered in down. Feathers with a side trunk.
They feed only in the sea, catching mainly in the water column fish and small invertebrates (mainly crustaceans). The tongue is fleshy, elongated, sometimes equipped with spikes in the main part, well adapted to hold prey. In adult Luricas and auk, feeding mainly on zooplankton, a sublingual sac is formed in which they bring food to the chicks. Due to protein nutrition, the glandular stomach is well developed, while the muscular stomach is small in volume.
The flight is swift, with many species having low maneuverability, with frequent flapping of wings. Primary flywheels 11 (first rudimentary). Steering short - 6-8 pairs. Often they rule using spread paws. The air bags are big.
The color of the plumage is two-tone (white bottom and dark top), dark, less often motley. There is no sexual dimorphism in color, but age and seasonal outfits differ.
Chistikov’s nests, as a rule, are mono- and polyspecific colonies, often large (more than 10 thousand individuals), geographically confined to food accumulation sites. Monogamy. Nest on rocks or in a layer of peat, openly or in shelters (in crevices, cavities among stones, in holes). These nests, as a rule, are not built. Only the long-billed fawn nests in the trees.
In the clutch one or two eggs. Both parents incubate, which form stained spots. Incubation takes 3-5 weeks. Chicks hatch sighted, dressed in dense fluff, which in open-nesting species changes to an intermediate outfit (mesoptile).
There is only one family (Alcidae) in the suborder, uniting 13 genera, in which there are a total of 22 species. A probable center for the formation of purebreds is the Bering Sea. Fossil remains are known from the Lower Eocene and later layers. According to them, 11 extinct species are described. Modern species found in the Pleistocene sediments. One species - the wingless eel - as a result of a high degree of adaptation to scuba diving, completely lost its ability to fly in the air. He was exterminated in the first half of the XIX century. Chistikovyh isolated from gulls in the course of adaptation to the aquatic lifestyle and development of fodder resources of the water column to a depth of several tens of meters. Modern species are common in the seas of the northern and temperate latitudes of the Northern Hemisphere.
For the fauna of the USSR, 20 species were recorded, of which 19 nest and only 1 (Aleutian fawn) is known as a vagrant.