Field signs. The small, elegant and relatively dlinnokryly of skuas, the size of a dove, but the more magnificent feathers and large wings is much larger. The main distinguishing feature - a long thin pair of central steering, they are issued by 14-20 cm over the edge and the tail in the air is soft kolyshutsya. Deep morfy this type do not have all the birds painted same type. There is no dark sling on the chest, yellowish-white color gradually shifts to the bottom of the body in a dark gray podhvostya. Two Legs: bobbin gray-blue, black fingers and the membrane. Coloring young diverse - from dark brown to gray Belesa, usually with the abundance of pestrin, the central pair of steering with rounded ends, is awarded for the tail cut by 2-4 cm, on the underside of the wing, one bright spot at the base of primary makhovaya. Poluvzroslye (3rd and 4 th calendar years) are similar to adults, but some places are pestriny (especially expressed on podkrylyah and podhvoste) and the short, 10-15 cm tail, and therefore easily confused with korotkohvostymi pomornikami. It should pay attention to color the bottom of the body (see above), in addition, the dlinnohvostyh skuas at this age, as adults, no bright spots on the upper surface of the wing, only white rods makhovaya. Weight 260-320 g body length 35-58 cm (such a wide range because of the changing length of the tail), wing 28,3-32,6 cm, the magnitude of 92-105 cm (Ryabitsev, 2001). When intra communicate in gnezdovoe time voice is a successive series of jerky yelling with plangent "kliiyayaaaa, kliiyayaaaa ..." Single pozyvki - CLE, "hev, hev-yev". Creek worries - short calls, "credit", the same issue in an attack on predator from the nest. In addition, signal attack - somewhat more prolonged "kyaaa" or "keee." Occasionally pischat when the place of jacks (Ryabitsev, 2001).  Distribution. Typical krugopolyarnaya tundrovaya bird, with its optimum Areli in subzone tepichnyh tundra, but is widely found throughout the zone. At the Northern Land enters into an area of polar desert and to the south in some places and in the forest. Summer kochevki and zalety in the boreal forest zone in Central Siberia is not marked (Rogacheva, 1988).
Habitats. Biotopes Characteristics: The subzone typical tundra - raw osokovo-moss papulose or spotty tundra in the downturn, as well as dry driadovo-moss tundra in the Arctic tundra - papulose-spotty tundra on the slopes uvalov and flat watersheds, less for lower in subzone bush tundra - dry moss-lishaynikovye tundra, spotty kustarnichkovye and osokovye tundra (Vinokurov, 1971; Vronsky, 1986; Chupin, 1987; Rogacheva, 1988). Phenology. Priletayut later than other skuas, in typical tundra - in mid-June, rarely in the week before. Fly in late August - early September (Syroechkovsky, Rogacheva, 1980). Reproduction. Nest satisfied anywhere in the dry and relatively sharp ground. It is simply better in the ground, without any special lining. In laying 2 eggs, but with low numbers of lemming can be only one. Coloring eggs on average darker than that of other skuas, olive, brown, greenish, dark-ohristaya, with brown and brown spots. The size of eggs 47-67 x 33-50 mm. Nasizhivayut alternating between the two member pair. All the big birds that are hazardous to the nest, fiercely struck and quickly drive away. Feel free to dive and people, but attacks (lapami or wing) to cause extremely rare. Sometimes the place, food and perebegaya far from the nest. The duration of one incubation eggs 23-25, the entire stack - 25-27 days. Flying beginning at the age of about 3 weeks (Ryabitsev, 2001). Nutrition. Core nutrition constitute Lemming and vole. If the little rodents, and overwhelm searching for birds' nests, catch chicks, offal picked up all possible, eat berries, but the major food substitute are insects. Dlinnohvosty skua, vysmatrivaya extraction, can hover in place, in fear and trembling wings, as the kestrel (Ryabitsev, 2001). The number varies depending on the abundance of rodents myshevidnyh (but less than that of other skuas). In good years is typical, poor - rare (Rogacheva, 1988). References. |
