Dipper

Dippers are members of the genus Cinclus in the bird family Cinclidae, named for their bobbing or dipping movements. They are unique among passerines for their ability to dive and swim underwater. The genus Cinclus was introduced by the German naturalist Moritz Balthasar Borkhausen in 1797 with the white-throated dipper (Cinclus cinclus) as the type species. The name cinclus is from the Ancient Greek word kinklos that was used to describe small tail-wagging birds that resided near water. Cinclus is the only genus in the family Cinclidae. The white-throated dipper and American dipper are also known in Britain and America, respectively, as the water ouzel (sometimes spelt 'ousel') – ouzel originally meant the only distantly related but superficially similar Eurasian blackbird (Old English osle). Ouzel also survives as the name of a relative of the blackbird, the ring ouzel. The genus contains five species: A 2002 molecular phylogenetic study of the dippers looked at the DNA sequences of two mitochondrial genes. It found that the Eurasian white-throated dipper and brown dipper are sister species as are the South American white-capped dipper and rufous-throated dipper. The study also showed that the dipper family, Cinclidae, is most closely related to the thrush family, Turdidae. Dippers are small, chunky, stout, short-tailed, short-winged, strong-legged birds. The different species are generally dark brown (sometimes nearly black), or brown and white in colour, apart from the rufous-throated dipper, which is brown with a reddish-brown throat patch. Sizes range from 14–22 cm (5.5–8.7 in) in length and 40–90 g (1.4–3.2 oz) in weight, with males larger than females. Their short wings give them a distinctive whirring flight. They have a characteristic bobbing motion when perched beside the water, giving them their name. While under water, they are covered by a thin, silvery film of air, due to small bubbles being trapped on the surface of the plumage. Dippers are found in suitable freshwater habitats in the highlands of the Americas, Europe and Asia. In Africa they are only found in the Atlas Mountains of Morocco. They inhabit the banks of fast-moving upland rivers with cold, clear waters, though, outside the breeding season, they may visit lake shores and sea coasts. Unlike many water birds, dippers are generally similar in form to many terrestrial birds (for example they do not have webbed feet), but they do have some morphological and physiological adaptations to their aquatic habits. Their wings are relatively short but strongly muscled, enabling them to be used as flippers underwater. They have dense plumage with a large preen gland for waterproofing their feathers. Relatively long legs and sharp claws enable them to hold on to rocks in swift water. Their eyes have well-developed focus muscles that can change the curvature of the lens to enhance underwater vision. They have nasal flaps to prevent water entering their nostrils.