Ijima's leaf warbler

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Ijima's leaf warbler
Warbler in Taiwan (April 2021)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Phylloscopidae
Genus: Phylloscopus
Species:
P. ijimae
Binomial name
Phylloscopus ijimae
(
Stejneger
, 1892)
Synonyms

Acanthopneuste ijimae (protonym)[2]
Acanthopneuste occipitalis ijimae[3]
Phylloscopus coronatus ijimae[4]
Phylloscopus tenellipes ijimae[5]

Ijima's leaf warbler (Phylloscopus ijimae) (also known as Izu leaf warbler, Ijima's willow warbler or Ijima's warbler) is a species of

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 Isao (1861–1921), whose name the warbler bears[2]

Ijima's leaf warbler is a

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

The eastern crowned warbler (Phylloscopus coronatus) may be distinguished by its crown stripe[15]

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 habitat

Ijima'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]

Ecology

Insects 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]

Conservation

The 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 also

References

External links