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Ijima's leaf warbler
Ijima's leaf warbler (Phylloscopus ijimae) (also known as Izu leaf warbler, Ijima's willow warbler or Ijima's warbler) is a species of Old World warbler in the family Phylloscopidae. The species is native to Japan, where it has been designated a Natural Monument under the 1950 Law for the Protection of Cultural Properties,[6] with records also from Taiwan and the Philippines.[1] Taxonomy Ijima's leaf warbler is a monotypic species first described by Leonhard Stejneger in 1892, based on three specimens collected in the spring of 1887 by Namie Motokichi on Miyake-jima and Nii-jima, in the Izu Islands of Tokyo.[2] Initially given the scientific name Acanthopneuste ijimae by Stejneger,[7] Momiyama Tokutarō followed suit in a 1923 paper on the birds of Izu Ōshima.[8]: 206 In a 1926 paper on a collection of birds from the Ryūkyū Islands, Kuroda Nagamichi treated the warbler instead as a subspecies of the western crowned warbler, as Acanthopneuste occipitalis ijimae,[3]: 85 Yamashina Yoshimaro following suit in 1935.[9]: 431 In 1938, Claud Ticehurst treated the warbler as a "race" of the eastern crowned warbler (Phylloscopus coronatus),[5][10] as did Allan Robert Phillips in 1947, based on three specimens from the southern part of Okinawa Island, the combination being Phylloscopus coronatus ijimae.[4] In 1953, citing differences in songs and nesting behaviours, Oliver L. Austin and Kuroda Nagahisa elevated the warbler to specific rank, with the binomial Phylloscopus ijimae,[11]: 543 a treatment followed the next year by Charles Vaurie[12]: 22 Kenneth Williamson treated the warbler as a subspecies of the pale-legged leaf warbler, under the combination Phylloscopus tenellipes ijimae;[5] however, due to differences in its vocalizations, nesting preferences, and DNA,[7] the warbler has again been elevated to species rank, as Phylloscopus ijimae.[13] The specific name honours Ijima Isao, for his contributions to Japanese ornithology.[2][14] Description Ijima's leaf warbler is a small passerine with a total length of 11.5 cm (4.5 in) and weight of around 10 g (0.35 oz).[16] The crown and nape are a greenish-grey, upperparts a bright olive green, flanks greyish, and underparts white.[7] It has a long white or buffish-white supercilium, blackish eyestripe, and dark brown iris.[7] The beak is relatively long and "broad-based", the upper mandible dark brown, the lower yellowish, and the legs and feet a pinkish brown.[1][7] The warbler is similar in appearance to the eastern crowned warbler (Phylloscopus coronatus), from which it may be distinguished visually by the absence of a central stripe on its crown and by its paler yellow undertail coverts.[7][15] Its song and calls, which include "swss, swss, swss", "swee-swee-swee-swee-swee", "shwee-it, shweet, shweet, shweet", and a soft "se-chui, se-chui, se-chui" and "phi-phi-phi",[7] also differ from those of the eastern crowned warbler.[17] Distribution and habitatIjima's leaf warbler breeds in the summer in the Izu Islands, from Izu Ōshima to Aogashima, and also on Nakanoshima in the Tokara Islands.[16][18] In the spring and autumn, there are records of its presence from Honshū (Shizuoka, Aichi, and Wakayama prefectures), Mizunoko-jima, Tanegashima, Yakushima, and Okinawa Island and the Yaeyama Islands in the Ryūkyūs.[16][18] Its wintering grounds are poorly understood; a small number may overwinter in the Izu Islands (Miyake-jima and Hachijō-jima[17]) and Ryūkyū Islands, while there are also records from Taiwan and Luzon in the northern Philippines.[15][18] It inhabits the "lowland deciduous and mixed subtropical evergreen forest" and laurel forest, including the forest edge, stands of alder (Alnus) and bamboo, and shrubland.[15][18] EcologyInsects form the principal component of its diet — when written in kanji (飯島虫喰),[17] the warbler's Japanese name reads as "Ijima's insect-eater" — which also includes seeds.[18] For these it forages, singly or in small groups (sometimes including other species, in particular long-tailed tits (Aegithalos caudatus)), on lower branches, in the forest canopy, and on the ground, and it may also take prey in mid-air.[18][19] The breeding season is from April to June or July.[16][18] Nests are built some 0.5–2 m (1 ft 8 in – 6 ft 7 in) from the ground,[7] on broad-leaved trees and in bamboo (this nesting behaviour differs from that of the eastern crowned warbler, which nests on the ground and in earthen banks).[18] The clutch size ranges from two to four eggs, with three or four the most common.[18] ConservationThe declining population, thought to total fewer than 10,000 individuals,[1] is threatened by habitat loss and fragmentation.[7][15] In addition, the availability of prey may be impacted by the use of pesticides.[18] The species was badly affected by the eruption of Miyake-jima in 2000.[18] With an estimated 3% of the global population, Phylloscopus ijimae (Chinese: 飯島柳鶯) is included on the 2016 Red List of Birds of Taiwan with the status "vulnerable".[20]: 38 (The species is also included on the 2016 Red List of China's Vertebrates (with the vernacular name 日本冕柳莺), with the status "near threatened".[21]: 523 ) In the Philippines, the species is included on the National List of Threatened Fauna, as a migrant bird on Luzon, with the status "vulnerable".[22] On the 2020 Japanese Ministry of the Environment Red List, Phylloscopus ijimae (Japanese: イイジマムシクイ) has the status "vulnerable",[23] as it had done also on the 1998 and 2007 editions.[16] See alsoReferences
External links Wikimedia Commons has media related to Phylloscopus ijimae. |
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