The Common Kingfisher, also known as Eurasian Kingfisher or River Kingfisher, is a small kingfisher with seven subspecies recognized within its wide distribution across Eurasia and North Africa. It is resident in much of its range, but migrates from areas where rivers freeze in winter.
This sparrow-sized bird has the typical short-tailed, large-headed kingfisher profile; it has blue upperparts, orange underparts and a long bill. It feeds mainly on fish, caught by diving, and has special visual adaptions to enable it to see prey under water. The glossy white eggs are laid in a nest at the end of a burrow in a riverbank.This species has the typical short-tailed, dumpy-bodied large-headed and long-billed kingfisher shape. The adult male of the western European subspecies, A. a. ispida has green-blue upperparts with pale azure-blue back and rump, a rufous patch by the bill base, and a rufous ear-patch. It has a green-blue neck stripe, white neck blaze and throat, rufous underparts, and a black bill with some red at the base. The legs and feet are bright red. It is about 16 centimetres (6.3 in) long with a wingspan of 25 cm (9.8 in), and weighs 34-46 grams (1.2-1.6 oz).
The female is identical in appearance to the male except that her lower mandible is orange-red with a black tip. The juvenile is similar to the adult, but with duller and greener upperparts and paler underparts. Its bill is black, and the legs are also initially black.
The flight of the Kingfisher is fast, direct and usually low over water. The short rounded wings whirr rapidly, and a bird flying away shows an electric-blue "flash" down its back.
In North Africa, Europe and Asia north of the Himalayas this is the only small blue kingfisher. In south and southeast Asia it can be confused with six other small blue-and-rufous kingfishers, but the rufous ear patches distinguish it from all but juvenile Blue-eared Kingfisher; details of the head pattern may be necessary to differentiate the two species where both occur.
The Common kingfisher has no song. The flight call is a short sharp whistle, chee, repeated two or three times. Anxious birds emit a harsh, shrit-it-it and nestlings call for food with a churring noise.
The Common Kingfisher is widely distributed over Europe, Asia, and North Africa, mainly south of 60°N. It is a common breeding species over much of its vast Eurasian range, but in North Africa it is mainly a winter visitor, although it is a scarce breeding resident in coastal Morocco and Tunisia. In temperate regions, this kingfisher inhabits clear, slow-flowing streams and rivers, and lakes with well-vegetated banks. It frequents scrubs and bushes with overhanging branches close to shallow open water in which it hunts. In winter it is more coastal, often feeding in estuaries or harbours and along rocky seashores. Tropical populations are found by slow-flowing rivers, in mangrove creeks and in swamps.
Common Kingfishers are important members of ecosystems and good indicators of freshwater community health. The highest densities of breeding birds are found in habitats with clear water, which permits optimal prey visibility, and trees or shrubs on the banks. These habitats have also the highest quality of water, so the presence of this bird confirms the standard of the water. Measures to improve water flow can disrupt this habitat, and in particular, the replacement of natural banks by artificial confinement greatly reduces the populations of fish, amphibians and aquatic reptiles, and waterside birds are lost. It can tolerate a certain degree of urbanisation, provided the water remains clean.
This species is resident in areas where the climate is mild year-round, but must migrate after breeding from regions with prolonged freezing conditions in winter. Most birds winter within the southern parts of the breeding range, but smaller numbers cross the Mediterranean into Africa or travel over the mountains of Malaysia into Southeast Asia. Kingfishers migrate mainly at night, and some Siberian breeders must travel at least 3,000 km (1,900 mi) between the breeding sites and the wintering areas.