In 2008, Phylloscopus borealis was divided to 3 species ; Japanese Leaf Warble P. xanthodryas, Kamchatka Leaf Warbler P. examinandus and Arctic Warbler P. borealis . Today's theme of this article is Kamchatka Leaf Warbler. I will show pics of 2 individuals. About 1 years ago, I wrote an article about Arctic Warblers, they observed in Yonaguni-island the most west in Japan during migration. But this article is not written in English, Japanese only so I'm sorry. Please see the pics from this article. (Here is the article) Kamchatka Leaf Warbler exhibit greenish-brown upperparts. The greenish tone of Kamchatka is darker than Arctic and little darker than Japanese Leaf. Face of Kamchatka Leaf is looks like "cool". Because of the narrow dark eye-stripe. I think it is one of the difference to Japanese Leafs. There are a large variation in pale supercilium in Kamchatka Leaf. This individual's supercilium connects on the bill. The length of outer-most primary of 3 species show differences, but there are a lot of overlap. Legs of Kamchatka Leaf is similar to Arctic, however a little pale. The songs of this species is "zizilo zizilo" or "bibilo bibilo". The songs of Japanese leaf is "chol chol chol".
オオムシクイ (Phylloscopus examinandus) Kamchatka Leaf Warbler 150604 Japan
Second individual. It has a little large bill. I observed it on July with recorded songs. I think the contrast between ear-coverts and eye-stripe of the Kamchatka Leaf is strong. On ethological view, I think there are differences. Especially in foraging, the posture in foraging of 3 species are different. Kamchatka Leaf often the body is laid during foraging and moving. It is rare that Kamchatka Leaf do flycatching on foraging unlike Arctic. But there are a big problem. It is that I didn't observe large number of Japanese Leafs during migration. I observed only breeding ground. So it is difficult to compare behaviors. I don't have books or thesis about molt. I wanna know about the molt of this species. In July, primaries are fresh.
エゾムシクイ (Phylloscopus borealoides) Sakhalin leaf-warbler 150513 Japan
Sakhalin Leaf Warbler is common in Japan and many people think it is easy to divide Sakhalin to Kamchatka. But it is not easy. Sakhalin has large variation on traits. Many books explain that Sakhalin Leafs are less greenish-tone. But some individual exhibit greenish-tone like this individual. The conclusion of this article is as below. We can identify easily Kamchatka Leaf to Arctic. But it is difficult to Japanese leaf. You should image what species you see, after that to identify with song or call. It is so excited so I recommend that method!