The blue nuthatch (Sitta azurea ) is a bird species in the nuthatch family Sittidae. It is a medium-sized nuthatch, measuring 13.5 cm (5.3 in) in length. The species, which shows slight sexual dimorphism, has dramatic coloration unlike any other member of its genus. Its head is black or blackish-blue dark blue upperparts close to purple with azure feathers. The wings are edged with black. The throat and chest are white or a washed buff color, contrasting with the upperparts and the belly of a very dark blue; the covert feathers are generally clear, blue-gray or purplish.
The blue nuthatch's ecology is poorly known, but it feeds on small invertebrates found on trees; reproduction takes place from April to June or July. It also forages in mixed-species flocks in larger groups. They can be found in the Malay Peninsula and on the islands of Sumatra and Java in Indonesia, where it inhabits subtropical or tropical moist lowland forest and subtropical or tropical moist montane forest above 900 m (3,000 ft) in altitude.
Three subspecies are recognized: S. a. expectata, S. a. nigriventer and S. a. azurea, which differ chiefly in the coloring of their mantles, chests and bellies. The species' closest relatives are the velvet-fronted nuthatch (S. frontalis ), the yellow-billed nuthatch (S. solangiae ) and the sulphur-billed nuthatch (S. oenochlamys ). The population of the species has not been determined but the species appears to be at low risk of extinction because of the extent of its distribution. It has been classified as of least concern by the International Union for Conservation of Nature.
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withThe blue nuthatch is a medium-sized nuthatch that has an average length of 13.5 cm (5.3 in). The weight is not known, but may be comparable to the Algerian nuthatch (Sitta ledanti ), which also measures 13.5 cm (5.3 in) long, and weighs between 16.6 g (0.59 oz) and 18 g (0.63 oz). Its appearance differs significantly from all other nuthatches. All of its subspecies are broadly black and white (especially when viewed in low-light conditions in which their dark blue coloring is not apparent) and have upper plumage shot through with dramatic notes of cobalt, azure and other lighter shades of blue, as well as grays and purples. The head is black, or blackish-blue with a broad, pale blue eye ring.
The three subspecies vary predominantly in the coloring of their mantles, chests and bellies. The upperparts are dark blue at the mantle or purplish in some subspecies. The rectrices, which are the tail's flight feathers, are pale blue in the middle with a black border and contrast sharply with the dark areas of the coat. The throat and breast are white, or washed buff, especially in S. a. nigriventer. The belly and abdomen are blackish, contrasting with blue-gray or purplish coverts. The bill is lavender, slightly tinged with green, and black at the tip; the legs are a pale blue-gray and the claws are slate or black.
The species displays no significant sexual dimorphism, but Japanese ornithologist Nagamichi Kuroda describes the female as having slightly duller upperparts. Juveniles resemble adults, but have a duller crown and ear coverts, as well as a brown cast that does not cover their entire body. The belly is a dull black and the undertail coverts are variably edged creamy white. The juvenile's bill is blackish, with a pink base. Adults experience a partial moult before the breeding season (February–March for S. a. expectata ; March–April for S. a. azurea ) involving the throat, chest and mantle; a complete moult takes place after the breeding season (March–April and August in Java in Malaysia).
This species lives in the Malay Peninsula (in extreme southern Thailand and northern Malaysia) and in Indonesia on the islands of Sumatra and Java. In Malaysia, the species has been observed in Bukit Larut, in the state of Perak, in the Titiwangsa Mountains, in southern Hulu Langat, in the state of Selangor, as well as some isolated populations on the slopes of the massive Mount Benom in the state of Pahang, on Mount Tahan located at the Pahang-Kelantan border, on Mount Rabong in Kelantan and at Mount Padang in the Sultanate of Terengganu.
In Sumatra, the bird is found throughout the Barisan Mountains, and has been observed in the Gayo Highlands of Aceh province, the Batak Highlands of northern Sumatra, and at Dempo in the south of the island. In a 1918 expedition by Robinson and Kloss, they commented: "from the commencement of heavy jungle on the valley slopes up to about 8,000 feet on Korinchi Peak this strikingly coloured little Nuthatch was very common, feeding on tall tree trunks in parties of six or seven."
The blue nuthatch is typically found on mountains, inhabiting subtropical or tropical moist lowland forest and subtropical or tropical moist montane forest. In Malaysia, it is found from 1,070 m (3,510 ft) to the highest point in the country at 2,186 m (7,172 ft). In Sumatra, the species has been reported at an altitudinal range of between 900 m (3,000 ft) and 2,400 m (7,900 ft), and on Java, between 915 m (3,002 ft) and 2,745 m (9,006 ft). Ornithologist John MacKinnon has reported some rare sightings at lower altitudes on the plains of Java.
The blue nuthatch is very active, often seen running in pairs, in larger groups, or mingling in mixed-species foraging flocks.
The blue nuthatch feeds on arthropods, of which some have been particularly identified as common in its diet, including Trachypholis beetles, click beetles, Eumolpinae leaf beetles, spiders, and moth caterpillars. It typically forages for prey in the upper half of large trees, and occasionally in smaller trees. While prospecting on tree trunks, the bird protects its corneas from falling bark and other debris by contracting the bare skin around its eyes – an adaptation apparently unique to the species.
The breeding of the species has not been extensively studied. The nest is made in a small tree hole in which it lays three to four dirty-white eggs, washed in lavender and densely speckled with reddish-brown and gray, that measure 19.3 mm × 13.4 mm (0.76 in × 0.53 in). In Peninsular Malaysia, juveniles just reaching maturity were observed in late June; on the island of Java, the breeding season takes place from April to July, and on Sumatra an adult feeding its young was observed on May 9.
The blue nuthatch is a common bird in Sumatra, including in the area of Kerinci Seblat National Park and relatively common in Malaysia and Java. It has a very wide distribution area, approaching 361,000 km2 (139,000 sq mi). The population has not been rigorously estimated but is considered significant and at low risk, despite BirdLife International's observation that some decline is likely (but not as yet confirmed) due to known destruction and fragmentation of areas the species is known to inhabit. The blue nuthatch is placed in the category of least concern by the International Union for Conservation of Nature.
