Javan Bush Warbler Locustella montis Scientific name definitions

14–15 cm; c. 11–14 g. A moderately large rusty-brown and grey, full-tailed bush-warbler. Adult nominate has rather weak greyish-white supercilium palest just above eye, merging into grey ear-coverts and neck-sides; lores dusky, malar region grey; dark reddish brown on crown, nape and upperparts, including wings, tail very dark grey with rufous wash; chin and throat whitish with greyish-black spotting, spots becoming heavier and forming necklace of dusky streaks across chest, variably extending to sides of neck and upper flanks; breast dark grey, flanks dark grey with rufous-brown wash, central belly whitish; undertail-coverts brown with whitish scaling; iris dark brown; bill blackish; legs dark greyish-pink. Sexes alike. Juvenile has pronounced yellowish wash on underparts, pale mandible, legs more pinkish than those of adult. Race timorensis distinguished by slightly smaller size, sleeker and slimmer-tailed appearance, less richly coloured overall plumage, less rufous above and paler below, longer supercilium, no dusky loral mark, less dark undertail.

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Bushes and grassy growth at forest edge, cleared slopes with scattered Casuarina trees and scrubby cover; also on open deforested slopes along rim of volcano craters above 1500 m, and up to 2100 m. On Bali, birds presumed to be of this species have been found in ferns and other dense vegetation at edge of forest, at 1200 m and 1500 m. On Timor-Leste reported in tall grassland at 1720–2100 m and on Alor in scrub and grass beneath woodland and forest edge at c. 860–1250 m.

Song of nominate race, generally from low down in dense cover, a buzzy “zeeep”, like that of L. mandelli but less disyllabic, preceded by very short, snappy double clip, thus “klpklpzeeep”, this phrase monotonously and rapidly repeated at rate of almost two notes per second for several minutes. Birds on Bali produce similar sound, but main song phrase has distinct downward inflection. Birds recorded in Alor (race timorensis) are substantially higher-pitched (mean minimum/maximum 3233–4980 kHz) than those recorded in E Timor (2928–4761 kHz), both being higher-pitched than nominate race and lower-pitched than L. mandelli; song of L. seebohmi is of a similar pitch to the Timor birds (4 Trainor, C. R., P. Verbelen, and S. Hoste (2012). Rediscovery of the Timor Bush Warbler Locustella timorensis on Alor and Timor, Wallacea: clarifying taxonomic affinities, defining habitat and survey recommendations. Bird Conservation International 22(3):354–369. Close ).

Not globally threatened (Least Concern). Nominate race is confined to Java and Bali Forests EBA. Common and widespread on volcanic slopes of C & E Java; its preference for higher elevations, where pressure from human habitation is low, and its fondness of open slopes, which have been cleared of trees, should not only ensure its survival but probably also allow an increase in its population. On Bali, known only from C part of the island, where it was discovered in 1989 above L Bratan, at 1200 m; has subsequently been found by Bedugul Botanic Garden, at 1500 m. Race timorensis present in Timor and Wetar EBA, and was long known from only two specimens, one of each sex, collected in 1932 near the top of Mt Mutis. Subsequent exploration of this area found that understorey of vegetation around the type location was severely degraded by overgrazing in 1989, and suggested that these sites may not now be suitable for it. There was a sight record at 1800 m near Same, in E part of the island (Timor Leste), in Aug 1972, but the supporting description mentioned a “lack of any supercilia”, which, on basis of current knowledge, seems incorrect for the species. Rediscovered on Alor I in Sept 2009, and in E Timor in Dec the same year (4 Trainor, C. R., P. Verbelen, and S. Hoste (2012). Rediscovery of the Timor Bush Warbler Locustella timorensis on Alor and Timor, Wallacea: clarifying taxonomic affinities, defining habitat and survey recommendations. Bird Conservation International 22(3):354–369. Close , 5 Verbelen, P. and Trainor, C. R. (2012). Rediscovery of the Timor Bush Warbler Locustella (Bradypterus) timorensis on Alor and Timor, Wallacea, Indonesia. BirdingASIA. 17: 47-48. Close ). In 2009–2010 at least 13 males heard singing on Alor and 40 males on E Timor. On Alor, suitable habitat is extensive and under little threat, but grasslands in the Timor uplands are intensively grazed and regularly burnt (4 Trainor, C. R., P. Verbelen, and S. Hoste (2012). Rediscovery of the Timor Bush Warbler Locustella timorensis on Alor and Timor, Wallacea: clarifying taxonomic affinities, defining habitat and survey recommendations. Bird Conservation International 22(3):354–369. Close ). Alor and Timor populations isolated and c 100 km apart. Further research needed.