left side of the basin. The right-side tributaries are typical mountain rivers whereas the left-side tributaries have flatland character. About from the mouth there is a dangerous spot for shipping called Kruglovskaya prorva ( meaning Kruglovsk abyss). Here the river narrows and creates a strong vortex over a deep pit. The climate is continental with frequent and strong winds. Typical annual precipitation is . Fauna The wetlands at and near the delta of the Ural River are especially important to migrating birds as an important stop-over along the Asian flyway. They host many endemic and endangered species, such as great white pelican, Dalmatian pelican, pygmy cormorant, cattle egret, little egret, greater flamingo, white-headed duck, ferruginous duck, Eurasian spoonbill, glossy ibis, houbara bustard, great black-headed gull, slender-billed gull, squacco heron, common crane, demoiselle crane, slender-billed curlew, black stork, red-breasted goose, lesser white-fronted goose, lesser kestrel, whooper swan, tundra swan, osprey, pallid harrier, short-toed eagle and many others. The pygmy cormorant was observed sporadically before 1999 and more regularly after that. Cattle egret is observed since 1990 between April and September (as most other migratory birds in this area), with the total population of several dozen couples. It feeds on frogs, mollusks and small fish. Upstream, there are more of the resident bird species, such as grouse, wild pigeon and partridge. Ural River is also important for many fish species of the Caspian Sea which visit its delta and migrate upstream for spawning. In the lower reaches of the river there are 47 species from 13 families. The family Cyprinidae account for 40%, sturgeon and herring make up 11%, perch and herring 9% and salmon 4.4%. The main commercial species are sturgeon, roach, bream, perch, carp, asp and Wels catfish. The rare species include Caspian salmon, sterlet, white salmon and kutum. In the delta of the river and nearby regions live about 48 animal species belonging to 7 orders; most common are rodents (21 species) and predators (12). Among them, Bobrinski's serotine and marbled polecat are endemic. Key species are raccoon dog, muskrat (appeared recently), European hare, house mouse, brown rat, and wild boar. Wild boars had a density of 1.2–2.5 per hectare in 2000 and are hunted commercially. Others include elk, fox, wolf, dwarf fat-tailed jerboa, great gerbil, northern mole vole and saiga antelope. The Turkmenian kulan (Equus hemionus kulan) used to live at the Ural River. It might be extinct