A couple of Phylloscopidae

There were 2 species of leaf warbler visiting the pool....................

The top one is a Kamchatka Leaf Warbler (part of the Arctic Warbler complex) and the second one is an Eastern-crowned Warbler.

KL Warblers breed in North Hokkaido and NE Siberia. As far as I know they are just passage visitors through my part of Hokkaido (the southwest). They were abundant in the forests around Shikotsuko and were singing everywhere. They are slightly duller than the EC Warblers and have a white vent and a plain crown.

Last year they weer scarce around the pool (I only saw one) but this year they were regular visitors. You can see the difference when the sun shines on them and they look much greener.

They also pass through Hakodate and I sometimes see them near my apartment. They migrate later than other leaf warblers..................

Arctic Warbler has been split into 3 species. All 3 are said to occur in Japan and they all look very similar and even have similar calls. Arctic Warbler, the nominate species, is found across Eurasia. Japanese Leaf Warbler breeds further south in Japan and Kamchatka Leaf Warbler breeds in north Hokkaido and Sakhalin/ Kamchatka. These are presumably the latter species and are just passing through.............

Note the plain head/crown and compare to Eastern-crowned Warbler............

This was also very common in the forest and this species breeds locally. It arrives and leaves earlier then the KLWs...............and looks, well, slightly different..........

It has a very different song.............

Like all Phylloscopidae they look pretty similar and can be tricky to ID when not calling or singing. I checked the previous 2 years photos from late spring in this location and the previous 2 years were nearly all ECWs (although I misidentified a couple on second looks), for some reason KLWs were a lot commoner this year at the pool.

There is 3rd leaf warbler in Hokkaido, the Sakhalin Leaf Warbler which has a very distinctive song/call and is browner than these 2 species. I didn't see any this spring at this location and none the previous 2 either. Maybe they prefer coniferous forests when they reach their breeding grounds?