Fakty o: Sri Lanka blue magpie
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The Sri Lanka blue magpie or Ceylon magpie is a brightly coloured member of the family Corvidae and found exclusively in Sri Lanka. This species is adapted to hunting in the dense canopy, where it is highly active and nimble. However, its flight is rather weak and rarely used to cover great distances. In spite of the Sri Lanka blue magpie's ability to adapt to the presence of humans, it is classified as being vulnerable to extinction due to the fragmentation and destruction of its habitat of dense primary forest in the wet zone of Southern Sri Lanka.
Description
The Sri Lanka blue magpie measures between 42–47 cm in size, and is larger than a mynah but smaller than a crow, with a sturdy bill. Its plumage is bright blue, with a reddish-brown or chestnut head, neck, and wing. The blue tail is long and graduated, with a white tip. The bill, legs, feet, and featherless eye ring of this species are all vibrant red. Both the male and female of the species share this description. The juvenile of this species has a plumage similar to that of an adult, but overall duller, with a brown eye ring and a greyish hue to its blue feathers, especially on its underside. Moulting season for Sri Lanka blue magpies is from August to November.
Taxonomy
The Sri Lanka blue magpie is a member of the order Passeriformes, in the family Corvidae.
The genus that this species belongs to is Urocissa, a group of Southeast Asian magpies, of which there are 5 known species total. They share a recent common ancestor with another genus of Asian magpies, Cissa. Both Urocissa and Cissa are genera of the Oriental region, where the diversity of corvid species originated. They share a distant common ancestor with new world jays and magpies.
Habitat and distribution
This species is endemic to Sri Lanka, where it is found in tall, undisturbed forest in the mountains, foothills, and adjoining lowlands of the wet zone. It is found from elevations of 2,135m to below 150m. It is not often seen in disturbed habitat such as gardens or plantations.
Surveys conducted from 2004-2006 found individuals of this species in 38 separate forest patches contained within 6 forest complexes within its range in the wet zone of Southern Sri Lanka.
Behaviour
In spite of their avoidance of human-disturbed habitats, research conducted at a highly visited nature trail in a forest reserve in Sri Lanka has shown that the Sri Lanka blue magpie tolerates and is even attracted to the presence of humans. In response to low and moderate levels of recreational disturbance, and small to medium-sized groups of human visitors, numbers of Sri Lanka blue magpies increased, unlike other birds included in the study. A group of individuals were often observed waiting near trails, expecting to be fed by groups of human visitors.
Vocalizations
The Sri Lanka blue magpie produces a great variety of vocalizations, including a jingle, a chink-chink, crakrakrakrak, and a whee-whee.
Thirteen different common call types have been identified for the Sri Lanka blue magpie, including mimicry calls. Individuals have been recorded using two raptor calls quite frequently, usually while mobbing a predator (the Accipiter high-pitched call and the Mountain Hawk Eagle (Nisaetus nipalensis kelaarti) call) These raptor calls are mimicked by another species that occupies the same region, the Greater racket-tailed drongo (Dicrurus paradiseus), implying that these imitated predator calls can act as alarm signals for multiple species.
Sri Lanka blue magpies don't just imitate the calls of predators, however. They have been observed mimicking the calls and songs of other birds in their prolonged and elaborate subsong.
Diet
These birds use their strong legs and feet to forage, and have been observed hanging upside down and holding down their prey with ease.
Their diet is mainly carnivorous, featuring insects, frogs and small lizards. However, they have been known to consume fruit as well, and some observations suggest that they also prey on eggs or young of other bird species. Sri Lanka blue magpies have been observed rubbing hairy caterpillars against mossy branches to remove irritating hairs prior to consuming them.
Reproduction
Sri Lanka blue magpies are monogamous, and use co-operative breeding to raise their young and can be seen in small flocks of up to 7 birds, while each bird maintains a territory.
The generation length of Sri Lanka blue magpies is 6.7 years. Breeding season is from January through March and 3-5 eggs, which are white covered with brown spots, are laid in a clutch. Cup-shaped nests are built atop small slender trees and lined with soft materials like lichen.
Both sexes build the nest and feed offspring with only the female incubating them.
Conservation status
The Sri Lanka blue magpie is listed as Vulnerable, due to the fragmentation and ongoing decline of the population. Surveys performed in 2004-2006 estimate the population at 10,181-19,765 individuals, although their breeding strategy of monogamy and co-operative breeding has led to that estimate being reduced to 9,500-19,500 individuals total to reflect their effective population size.
The main threat to the survival of the Sri Lanka blue magpie is habitat loss due to forest being cleared for agricultural land, mines, logging, and human settlement. A moratorium on logging in wet zones in 1990, plus the legal protection of this species in Sri Lanka have the potential to slow their population decline, but air pollution causing forest die-back and the use of biocides in the hill country continue to threaten the Sri Lanka blue magpie.
It has been suggested that one of the factors preventing the Sri Lanka blue magpie from moving into disturbed habitat is the presence of another bird, the Asian koel (Eudynamys scolopacea) which is a brood-parasite.
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