Blyth's kingfisher (Alcedo hercules) is the largest kingfisher in the genus Alcedo. Named for Edward Blyth, the species has also been known as Alcedo grandis and as the great blue kingfisher. Between long, the kingfisher has deep rufous underparts with a blackish blue breast patch, and brilliant cobalt blue or azure upperparts, tinged with purple. The wings are a dark blackish green, with blue speckles and tips to some of the feathers. The bill of the male is entirely black, while the female has a dark red lower mandible. The species is distinguished from the similar blue-eared kingfisher (Alcedo meninting) and common kingfisher (Alcedo atthis) by its greater size, heavy black bill, and dark lores.
The species breeds between the months of March and June. It builds nests at the end of tunnels dug in the banks of streams or ravines. Four to six eggs are laid, with both sexes incubating. A shy bird, it frequents small waterways, feeding on fish and insects caught by diving from a shrub close to the water. It is found along streams in evergreen forest and adjacent open country between , mainly between . The species ranges from Nepal through India, Bangladesh, Bhutan, China, Myanmar, Thailand, Laos, and Vietnam. Even within its preferred habitat the density of the species is low, and the population, though not thoroughly surveyed, is believed to be small, and declining further. The International Union for Conservation of Nature classifies it as "near threatened".
Taxonomy
Blyth's kingfisher was described by the English zoologist Edward Blyth in 1845 and given the binomial name Alcedo grandis. Unfortunately, this name was preoccupied as it had already been introduced for another species by the German naturalist Johann Friedrich Gmelin in his Systema naturae of 1788. In 1917, the German naturalist Alfred Laubmann proposed the binomial name Alcedo hercules to replace the preoccupied name chosen by Blyth. The common name commemorates Edward Blyth (1810–1873), who was the curator of the Museum of the Asiatic Society of Bengal. Blyth's kingfisher is most closely related to the blue-eared kingfisher (Alcedo meninting). The species is monotypic. It has also been referred to as the great blue kingfisher.
Description
Blyth's kingfisher is between in length, making it the largest of the Alcedo kingfishers. The wing of the male is between long, and that of the female between . On the male, the feathering on the head is black, with shiny tips of bright blue. It has a neck patch that is whitish or buff in colour, as is the chin. The breast and belly are rufous, except for a dark blackish-blue patch on the breast. The legs and feet of the bird are also red. The bill is entirely black in the male, while the female has a red base to the mandible. The iris of the bird is reddish brown. The lores of the bird are black, and have a buff coloured streak above them. The back of the bird from mantle to the tail coverts is a bright cobalt blue or azure, with a tinge of purple towards the rump and the tail coverts. When the bird is at rest, the upper parts may appear brownish black. The tail itself is a darker ultramarine blue. The wings and the scapular feathers are a dark greenish black. The feathers of the upperwing coverts have cobalt-blue tips, while the underwing coverts are dark rufous-red. The lesser and median coverts have prominent speckles of cobalt. Any distinctive features in the plumage of the juvenile are not known.
The species is morphologically similar to the blue-eared kingfisher (Alcedo meninting), but in comparison is substantially larger. Its bill is heavier and longer than that of the blue-eared kingfisher, and is entirely black. Its crown and wings are less brilliant as those of the smaller bird, and it may be distinguished by the speckles of light blue on its crown and wing coverts. The dark ear coverts set it apart from the common kingfisher (Alcedo atthis), which has rufous ear-coverts. It is similar to the female blue-banded kingfisher (Alcedo euryzona), but the two species do not overlap in their range.
The call of the species is described as a loud "pseet", less shrill but louder and more hoarse than that of the common kingfisher, and similar but louder to that of the blue-eared kingfisher. One of the calls made by the slaty-backed forktail (Enicurus schistaceus) is sometimes mistaken for the call of Blyth's kingfisher.