Ijima's Leaf Warbler

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). The crown and nape are a greenish-grey, upperparts a bright olive green, flanks greyish, and underparts white. It has a long white or buffish-white supercilium, blackish eyestripe, and dark brown iris. The beak is relatively long and "broad-based", the upper mandible dark brown, the lower yellowish, and the legs and feet a pinkish brown. 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. 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", also differ from those of the eastern crowned warbler.

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. 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. Its wintering grounds are poorly understood; a small number may overwinter in the Izu Islands (Miyake-jima and Hachijō-jima) and Ryūkyū Islands, while there are also records from Taiwan and Luzon in the northern Philippines. 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.

Insects form the principal component of its diet — when written in kanji (飯島虫喰), the warbler's Japanese name reads as "Ijima's insect-eater" — which also includes seeds. 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. The breeding season is from April to June or July. Nests are built some 0.5–2 m (1 ft 8 in – 6 ft 7 in) from the ground, 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). The clutch size ranges from two to four eggs, with three or four the most common.