Tuesday, 24 April 2012

Bradypterus Sp.

Recently I've been seeing more Bradyterus bush warblers than usual, which is not a problem at all. In fact, they're probably my most favourite group of warblers. They're extremely shy, secretive and difficult to get the exact identification. There are 4 species of bradypterus bush warblers in Thailand; Brown, Russet, Chinese and Baikal Bush Warbler. It's quite unbelievable that in a short period time, roughly just about one month, I saw all of the 4 species! This post will be all about my love for these bradypterus bush warblers.

Singing Brown Bush Warbler

Checking me out after hearing the playback

The first one here is the Brown Bush Warbler (Bradypterus luteoventris) that I recently saw at Doi Lang on April 22. It's a rare bradypterus of high mountains in northern Thailand. Similar to other bradypterus bush warblers, it prefers open areas, forest clearings and forest edge. Its status in Thailand is still questionable whether it is resident or winter visitor. I personally think that it's a resident bird since I've heard its unmistakable song several times during summer and rainy season before.

This time at Doi Lang, I heard its song coming from a distance as I was walking through a grassy patch in the middle of the forest just a little after sunrise. I walked towards the sound and tried using the play back. The bird responded quite immediately. It came flying into the bush next to me and checked out if there's another bird around or not. I then stopped the playback as soon as the bird showed up afraid of scaring it away from its own territory. The bird then flew to another bush on the other side of the track that I was standing and went up to the top of the bush and started singing. Its unmistakable, sewing machine-like song can be heard clearly in the video. It put up a great show for almost 5 minutes before going back into the bush. I then left the place and let it sing its heart out throughout the morning.

Singing Russet Bush Warbler

Note relatively long tail with whitish tips to undertail coverts

Another species of bradypterus bush warbler that I saw at Doi Lang was the Russet Bush Warbler (Bradypterus mandelli). It is a resident bradypterus of high mountains in northern Thailand. It prefers the same habitat as the Brown Bush Warbler. It's actually the main target for my visit to Doi Lang, but it turned out that I couldn't get ant decent photo of it. It has a few totally different habits from the Brown Bush Warbler. First, it doesn't sing from an open perch and second, it doesn't respond to playback immediately. It would keep silent for about 3 minutes before singing back. While it keeps being silent, it would search through the bushes for the other bird. After 3 minutes have passed, it would start singing its loud (much louder than those of the Brown Bush Warbler), insect-like song from inside the bush.

Above are my 2 best effort of getting its photo. The first one shows the almost completely concealed bird singing. I just noticed from the photo that it has yellow gape. The second shot shows the bird being concealed by grass once again, but at least you can see its relatively long tail and undertail coverts with buffish fringes. You can also see that it has almost completely dark bill different from Brown Bush Warbler. Even though it is extremely shy and difficult to see, it seems to be pretty common since I could hear its song almost in every grassy area that I visited. For a much better photo of this species, click here to see a photo from west Sikkim, India by Adesh Shivkar.

Adult Chinese Bush Warbler

Showing relatively long tail and plain whitish undertail coverts

The third species is the Chinese Bush Warbler (Bradypterus tacsanowskius). It's a very little known and rare winter visitor to northern Thailand. It mostly prefers reedbeds in low wetlands and riversides, but can also be found on high mountains during migration. I luckily found this bird at Doi Angkang on April 1. I first heard its typical tuk tuk call from the bush close to me. I then tried to mimic the call and quite unbelievably it came out from the bush and perched still for about 1 minute. I struggled throughout the whole 1 minute trying to focus at the bird but it was really difficult as the bush was really thick. I had to use manual focus to get these shots. At that time I had no idea what the bird was.

After checking the photos and consulting with other experienced birders, I could come to the conclusion that it's really a Chinese Bush Warbler, and probably a female judging from its pale lower mandible. It shows plain whitish throat and breast, completely no sign of spot or streak, with a relatively long tail and plain whitish undertail coverts different from other species of bradypterus bush warblers. Actually, the undertail coverts are not totally plain. The plain undertail coverts that we see is actually the effect of very broad whitish fringes. The centres of these undertail coverts are actually brownish but normally concealed by the broad fringes.

Adult Baikal Bush Warbler in non-breeding plumage

While giving its loud alarm call

Showing its unmistakable undertail coverts

The last species of bradypterus bush warbler to be presented here is the Baikal Bush Warbler (Bradypterus davidi). It is the commonest of the 4 species of bradypterus bush warblers in Thailand. It is a widespread winter visitor that can be easily distinguished from other bradypterus by the combination of spotted upper breast and unmistakable undertail coverts pattern. These photos were taken just from my local patch near Mae Taeng River. There seemed to be a good number of this bird around here. I could hear its loud alarm call coming from different directions in early morning. Its song can also be heard occasionally. Just like other bradypterus, it mainly forages by walking on the ground. It can look superficially similar to small rodents while walking or running. This is what makes Bradypterus bush warblers different from Cettia bush warblers, since cettia bush warblers would only hop on the ground.

Another individual with more pronounced black spots on upper breast

The bill will change into black/dark greyish in breeding plumage.


  1. Looking at your images, I can tell that these fellows are certainly a challenge for photographers. Great effort by the way.

  2. Thanks for the "instant guide to bradypterus warblers".... they're really a challenge !

  3. Wow! Great specialist post. You are so patient getting these records and although we can easily see their differences here I understand that when they're hopping about in the undergrowth you can barely see any of their markings for more than a glimpse. They are beauties however, so I understand your love for them. Super birding!!