Alcedo atthis, Common Kingfisher, Raja udang erasia

Written by on November 19, 2010 in Bali Bird with 0 Comments

Alcedo atthis, Common Kingfisher, Raja udang erasia Common Kingfishers are among the few Kingfishers that specialise iAlcedo atthis, Common Kingfisher, Raja udang erasian fishing. They are well known for plunging into the water to catch their prey: mainly small fish (60%) and prawns (30%), although they do pick off crabs and small mudskippers from mudflats. Common Kingfishers prefer to hunt in shallow water which gives them better accuracy.

Common Kingfishers usually perch on a convenient branch or pole about 1-2m from the water surface. They plunge into the water from their perch (90%); or hover before diving in (3%). They have keen eyesight with polarising filters to cut out water reflection and better see their prey. They also learn to compensate for refraction. When they plunge into the water, the eyes are protected by a membrane. So they actually catch their prey blind, relying on touch to decide when to snap their bills shut. They then fly straight out of the water with their prey in their bills.

Before eating a fish, the bird will hold it by its tail and whack it to death against the perch, particularly fishes with poky fins. Otherwise, the live fish may extend its fins in the bird’s throat, choking it, sometimes to death. Kingfishers regurgitate pellets of indigestible fishbone. The birds preen themselves carefully after fishing to ensure their feathers remain waterproof. Juveniles often nearly drown because they failed to pay enough attention to preening.

Common Kingfishers are solitary and highly territorial because they have to eat about 60% of their body weight a day. They fiercely defend their feeding grounds, even from their mates and offspring. When contesting territory, they perform a ritual display perched some distance from each other. This involves displaying feathers and beaks, accompanied by whistling. Usually the dispute is resolved without actual combat. But in rare instances, combatants will lock beaks and attempt to drown each other.

Breeding: Common Kingfishers seen in Singapore are visitors and breed in Northern Asia (e.g., Taiwan, Korea). But there is a small resident population in peninsular Malaysia. For those in Europe, courtship involves chasing and calling and usually culminates in the male catching and offering the female an "engagement fish".

Common Kingfishers nest on steep river banks, or even active termite mounds, digging out a tunnel that ends in a chamber. 4-8, usually 2, white eggs are laid, incubated by both parents in 18-21 days. Both parents raise the young. The chicks fledge in about 23-24 days. Mortality rates can be as high as 50%.

For more about the hunting methods and breeding habits of Kingfishers in general.

Migration: Common Kingfishers that breed far north migrate to the south, usually travelling at night. They may travel past the breeding grounds of more southerly residents, and go all the way to eastern Indonesia. In Singapore, they are more common in August to April.

Status and threats: The Common Kingfisher is not at risk in Singapore where they are found near open streams, canals, reservoirs, ponds and along the coasts. They are usually not found in forests or densely forested streams.

Main features: Small (17cm, 27-36g); upperparts turquoise-green, underparts pale to mid-orange; throat white; head sides white with rufous ear coverts; bill black; feet tiny, red.

Male: Bill all black.

Female: Bill mandible base orange.

Juvenile: Bill as in female, may have a white tip; upper parts paler and duller; sooty fringing across breast.

Call: Described as a trill; shrill, high-pitched seep-seep, repeated 2-3 times, usually in flight.

In flight: Bright metallic green-blue back and rump. Flight is direct and low.

Similar birds: Other kingfishers are much larger; lacks white head sides.

Status in Singapore: Very common winter visitor throughout the island and North and South offshore islands.

World distribution: Throughout Old World to New Guinea and Pacific Islands, but not in Australia.

Classification: Family Alcedinidae, subfamily Alcedininae. World 26 species, Singapore 2 species. There are 9 subspecies of the Common Kingfisher.

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