IJIMA'S LEAF WARBLER
15 February 2005: Fergus Crystal
Ijima's Warbler: Southern Osumi 2003 and Tokara Islands 2004
In early autumn 2003 I recorded Ijima's Warbler, Phylloscopus ijimae on return migration around Inaodake (at 930 meters above sea level), near the tip of the southern Osumi Peninsula in Kagoshima-ken. Based on sightings there throughout September, I think this species is a fairly common migrant within its restricted range, mostly in stretches of evergreen forest 800-930 masl on the three mountains that span the peninsula: Tsujidake, Kobadake and Inaodake. Most sightings were recorded at the latter site. In 2004, I visited the Tokara Islands in the north Nansei Shoto (Kagoshima-ken) eight times; islands visited were Nakanoshima, Tairajima, Suwanosejima and Akusekijima. I counted the number of singing males of Ijima's Warbler, along certain trails on the islands. I plan to return in March/April 2005 to census the same trails. I also had some experience of Ijima's Warbler prior to autumn 2003 on Nakanoshima, a known breeding site. I learnt the song and call of this species and watched two individuals being banded and measured. Below is a description of the songs and calls, followed by Tokara Islands observations.
Song: A high, breezy 'swisswisswisswiss!' with an 'electric' quality that recalls an automobile alarm. Often interspersed are two descending breezy whistles, 'tseeoo.. tseeoo...', very like the notes given in the 'parachute display' song of the Tree Pipit, Anthus trivialis. Sometimes a slowed-down version is given, 'tsu wiss tsu wiss tsu wiss tsu wiss tsu...', which sounds like the Tree Pipit's closing series of whistles. The 'tsu' is downward inflected and the 'wiss' inflects upward. It is very important to get acquainted with the call, as lack of recordings or information about it in field guides is probably why the species is under-recorded on migration and why the wintering grounds have yet to be discovered. The most common call, given as a contact note between pair members in the breeding season, and by singles or groups following tit parties on migration, is a loud, slightly downward-inflected 'tiu' with a melancholy ring. It is similar to a contact call regularly given by Coal Tit (Parus ater), but Ijima's call sounds more tunefully 'piped' and slightly deeper; some Great Tits (P. major) give a similar but again less 'piped' call, but this is rarely heard. Ijima's call is quite different from the hard, sharp 'dzeet' call given by Arctic Warbler (Phylloscopus borealis), and the softer but straight 'jeet' given by Eastern Crowned Warbler (P. coronatus). These in turn are different from the whistled, Red-flanked-Bluetail-like 'heep' given insistently by feeding Sakhalin Warbler (P. borealoides) and Pale-legged Leaf Warbler (P. tenellipes). I have yet to record the latter two species on migration in southern Osumi.
Ijima's Warblers feed in 10-meter-high evergreen trees, among the crowns, at Inaodake and Kabadake, often fluttering down to branches 2 m from the ground. They are more active than Arctic Warblers when feeding, and were quite unafraid of my presence: often birds would approach me inquisitively to about 2 m. At Tsujidake, birds were found 15 m up in the foliage of taller evergreen trees. Birds were seen singly, and in twos and threes (and a six!), often accompanying parties of Long-tailed Tits,Aegithalos caudatus.
In the Tokara Islands, males sing from branches 2-10 meters off the ground, normally in Ryukyu Pines, but also, in the east of Nakanoshima (the main breeding site), in Ryukyu Bamboo having only one or two shrubs or stunted trees within the bamboo stand. Tolerance of bamboo may be good news, as it indicates this species could utilise such habitats on nearby islands. The singing posture is hunched, with the head slightly tipped back, wings held close to body and legs stretched straight. The head is moved rhythmically from side to side during renditions and the tail and body shiver. Singing occurs from the end of March (arrival) to at least the beginning of July. Departure is probably in mid-August.
15 February 2005: Fergus Crystal
Ijima's Warbler: Southern Osumi 2003 and Tokara Islands 2004
In early autumn 2003 I recorded Ijima's Warbler, Phylloscopus ijimae on return migration around Inaodake (at 930 meters above sea level), near the tip of the southern Osumi Peninsula in Kagoshima-ken. Based on sightings there throughout September, I think this species is a fairly common migrant within its restricted range, mostly in stretches of evergreen forest 800-930 masl on the three mountains that span the peninsula: Tsujidake, Kobadake and Inaodake. Most sightings were recorded at the latter site. In 2004, I visited the Tokara Islands in the north Nansei Shoto (Kagoshima-ken) eight times; islands visited were Nakanoshima, Tairajima, Suwanosejima and Akusekijima. I counted the number of singing males of Ijima's Warbler, along certain trails on the islands. I plan to return in March/April 2005 to census the same trails. I also had some experience of Ijima's Warbler prior to autumn 2003 on Nakanoshima, a known breeding site. I learnt the song and call of this species and watched two individuals being banded and measured. Below is a description of the songs and calls, followed by Tokara Islands observations.
Song: A high, breezy 'swisswisswisswiss!' with an 'electric' quality that recalls an automobile alarm. Often interspersed are two descending breezy whistles, 'tseeoo.. tseeoo...', very like the notes given in the 'parachute display' song of the Tree Pipit, Anthus trivialis. Sometimes a slowed-down version is given, 'tsu wiss tsu wiss tsu wiss tsu wiss tsu...', which sounds like the Tree Pipit's closing series of whistles. The 'tsu' is downward inflected and the 'wiss' inflects upward. It is very important to get acquainted with the call, as lack of recordings or information about it in field guides is probably why the species is under-recorded on migration and why the wintering grounds have yet to be discovered. The most common call, given as a contact note between pair members in the breeding season, and by singles or groups following tit parties on migration, is a loud, slightly downward-inflected 'tiu' with a melancholy ring. It is similar to a contact call regularly given by Coal Tit (Parus ater), but Ijima's call sounds more tunefully 'piped' and slightly deeper; some Great Tits (P. major) give a similar but again less 'piped' call, but this is rarely heard. Ijima's call is quite different from the hard, sharp 'dzeet' call given by Arctic Warbler (Phylloscopus borealis), and the softer but straight 'jeet' given by Eastern Crowned Warbler (P. coronatus). These in turn are different from the whistled, Red-flanked-Bluetail-like 'heep' given insistently by feeding Sakhalin Warbler (P. borealoides) and Pale-legged Leaf Warbler (P. tenellipes). I have yet to record the latter two species on migration in southern Osumi.
Ijima's Warblers feed in 10-meter-high evergreen trees, among the crowns, at Inaodake and Kabadake, often fluttering down to branches 2 m from the ground. They are more active than Arctic Warblers when feeding, and were quite unafraid of my presence: often birds would approach me inquisitively to about 2 m. At Tsujidake, birds were found 15 m up in the foliage of taller evergreen trees. Birds were seen singly, and in twos and threes (and a six!), often accompanying parties of Long-tailed Tits,Aegithalos caudatus.
In the Tokara Islands, males sing from branches 2-10 meters off the ground, normally in Ryukyu Pines, but also, in the east of Nakanoshima (the main breeding site), in Ryukyu Bamboo having only one or two shrubs or stunted trees within the bamboo stand. Tolerance of bamboo may be good news, as it indicates this species could utilise such habitats on nearby islands. The singing posture is hunched, with the head slightly tipped back, wings held close to body and legs stretched straight. The head is moved rhythmically from side to side during renditions and the tail and body shiver. Singing occurs from the end of March (arrival) to at least the beginning of July. Departure is probably in mid-August.
Identification: Criteria in the literature are still poorly defined, and their development seems to be impeded by the insistent use in field guides of photographs as the sole concrete evidence of a bird's appearance. This species is readily separable from Eastern Crowned Warbler, as long as you get a decent view of the crown and head. Several birders have questioned my sightings, reasoning that some first-year Eastern Crowned have weaker or reduced central crown stripes, but out of many sightings in the Inaodake area of the warblers in question, none showed any trace of central crown stripes and most of them were giving Ijima's calls. All birds had the grayish dusty wash to crown and ear coverts (creating a gentle look) which I think is characteristic of Ijima's.
I recorded Eastern Crowned Warbler twice in Autumn 2003, at Kobadake on 30 August with one Ijima's, and at Tsijidake on 13 September. I noted their different call (and a burst of characteristic song from the latter bird) and darker crown (apart from the stripe), which extends neatly to the upper ear coverts and produces a capped effect. Both species appear to show dirty white underparts and a pale yellow wash to the ventral area. The underparts of Ijima's appear slightly paler and cleaner.
Separation from the slightly larger and darker Arctic Warbler was not that difficult, given good views. Arctic Warbler ssp xanthohydras were noted on two occasions with Ijima's in mid-September, when they remained apart and moved with characteristic sluggish movements, hopping heavily on branches while feeding (Ijima's makes quick darts along branches and acrobatic flutter-jumps while feeding, lighter actions than even Eastern Crowned, and reminiscent of Yellow-browed Warbler, P. inornatus). All Arctic Warblers seen showed strong bills and a characteristic thick-necked profile when the head was stretched; they also showed dull greenish crowns lacking central stripes, with more diffuse gradation into the ear coverts (which evinced some grayish streaking cutting into the green). They had dirty white underparts marked with an irregular, diffuse yellow wash, and a rather obvious yellow wash to vent and undertail—all characteristics of ssp xanthohydras. I once recorded what I think were a pair of nominate borealis near a group of Ijima's at Inaodake on 24 August 2003. The male gave a shimmering song similar to birds in Finland; this was a much faster, frizzling trill than the 3-tone ratcheting scramble of notes given in a sequence by xanthohydras. Both individuals called a dipper-like 'dzeet' in contact and lacked any hint of yellow to the off-white underparts.
Nakanoshima: on a 9-km walk around the central/eastern area of the island from the village via the eastern fields to the cattle fields (about one-third of the island`s area) on 17 April 2004, I recorded 135 singing males-- 65 in the eastern pine woods, 30 in the woods surrounding the farm, and 40 in the mixed forest slopes above the village. Total island population based on habitat availability is around 1000 birds, with 300-400 singing males. Six of the males recorded in the eastern area were in stands of bamboo with almost no trees. Akusekijima: no birds noted on 8 May 2004. Tairajima: none noted 22 May 2004. Suwanosejima: five singing males found on extensive walks around the southern part of the island (in pine woods, particularly in gullies) on 26-27 June 2004. Some presumed females noted on territory, but no proof of breeding. There are probably fewer than 10 pairs on the island annually. Kuchinoshima: I still have not visited this island, but a small number (1-10 pairs) apparently breed there (per Ogura Takeshi).
28 February 2005: Yoshiki Watabe
RE: Ijima's Warbler
Call: During a discussion on warblers included in the 2001 Annual Meeting of the Ornithological Society of Japan, one scholar said that the song of Ijima's Warbler could be classified into two types: one (type A) is the lower and slower 'chui-chui-chui', and the other (type B) is the higher and faster 'shiri-shiri-shiri'. The response to playback of the recorded songs of this species consisted of type B song. He stated that Nakanoshima individuals sang type A more often than type B, compared with Miyakejima individuals. As the lower song (type A) can travel a longer distance without modulation, the individuals of Nakanoshima may have inherited a greater tendency to select the type B song compared with Miyakejima birds. These results and discussion, however, have not been published.
I think the call of Ijima's Warbler is rather similar to Sakhalin Leaf Warbler, but longer. Ijima's call is a downward-inflected 'hee' or 'pwee' as Fergus mentioned, while Sakhalin's call is a short and metallic 'pit'.
Identification: I think that the facial impression of Ijima's is rather different from all other Japanese Phylloscopus. The supercilium is usually narrower than Arctic, Sakhalin and Eastern Crowned Warblers, and is straight. The eyestripe behind the eye is also usually narrower and paler than Arctic, Sakhalin and Eastern Crowned Warblers. The width of Ijima's eye-stripe is often slightly narrower than the eye width, while those of Arctic, Sakhalin and Eastern Crowned are equal to their eye width.
Ijima's Warbler prefers broad-leaved evergreen forest. When I carried out a survey on Mikurajima in spring 1995, I noticed that this bird always occurred near broad-leaved evergreen trees . If the bird was seen in bamboo forest, evergreens certainly occurred nearby. Takagi and Higuchi (2000) suggested that Ijima's Warblers are particularly associated with mature continuous forests, and that Laurel forest provides more suitable habitat for them than does deciduous forest. Tolerance of bamboo in Fergus' report is good news, but I think that Ijima's Warbler does not prefer this habitat; so if bamboo increases, Ijima's Warbler will decrease.
References:
Higuchi, H., 1973. Birds of the Izu Islands (I) Distribution and habitat of breeding land and freshwater birds. Tori. 93/94: 14-24.(in Japanese)
Takagi, M. and H. Higuchi, 2000. Habitat Selection by Ijima's Willow Warbler Phylloscopus ijimae on Miyakejima, Japan. Jpn, J. Ornithol. 49: 113-117.
28 February 2005: Yoshiki Watabe
RE: Ijima's Warbler
Call: During a discussion on warblers included in the 2001 Annual Meeting of the Ornithological Society of Japan, one scholar said that the song of Ijima's Warbler could be classified into two types: one (type A) is the lower and slower 'chui-chui-chui', and the other (type B) is the higher and faster 'shiri-shiri-shiri'. The response to playback of the recorded songs of this species consisted of type B song. He stated that Nakanoshima individuals sang type A more often than type B, compared with Miyakejima individuals. As the lower song (type A) can travel a longer distance without modulation, the individuals of Nakanoshima may have inherited a greater tendency to select the type B song compared with Miyakejima birds. These results and discussion, however, have not been published.
I think the call of Ijima's Warbler is rather similar to Sakhalin Leaf Warbler, but longer. Ijima's call is a downward-inflected 'hee' or 'pwee' as Fergus mentioned, while Sakhalin's call is a short and metallic 'pit'.
Identification: I think that the facial impression of Ijima's is rather different from all other Japanese Phylloscopus. The supercilium is usually narrower than Arctic, Sakhalin and Eastern Crowned Warblers, and is straight. The eyestripe behind the eye is also usually narrower and paler than Arctic, Sakhalin and Eastern Crowned Warblers. The width of Ijima's eye-stripe is often slightly narrower than the eye width, while those of Arctic, Sakhalin and Eastern Crowned are equal to their eye width.
Ijima's Warbler prefers broad-leaved evergreen forest. When I carried out a survey on Mikurajima in spring 1995, I noticed that this bird always occurred near broad-leaved evergreen trees . If the bird was seen in bamboo forest, evergreens certainly occurred nearby. Takagi and Higuchi (2000) suggested that Ijima's Warblers are particularly associated with mature continuous forests, and that Laurel forest provides more suitable habitat for them than does deciduous forest. Tolerance of bamboo in Fergus' report is good news, but I think that Ijima's Warbler does not prefer this habitat; so if bamboo increases, Ijima's Warbler will decrease.
References:
Higuchi, H., 1973. Birds of the Izu Islands (I) Distribution and habitat of breeding land and freshwater birds. Tori. 93/94: 14-24.(in Japanese)
Takagi, M. and H. Higuchi, 2000. Habitat Selection by Ijima's Willow Warbler Phylloscopus ijimae on Miyakejima, Japan. Jpn, J. Ornithol. 49: 113-117.