The Acrocephalus Issue

When talking about Little Brown Jobs (those small brownish birds that are difficult to identify), most birders in Thailand would immediately think of Phylloscopus warblers simply because there are so many of them. But for me, I’d say there are birds that are even more frightening to identify, the Acrocephalus warblers!


Oriental Reed Warbler is the commonest and most widespread reed warbler in Thailand.


Mostly seen foraging along scrubs and grassy area near water.



Frequents perching on open branches to dry itself in the morning. Note whitish tips to the tail feathers.


Can be quite showy and perches on grass tops for a look out or to sing


Note long and pointed primary projections


Often shows hint of greyish streaking on breast (more prominent in spring)

There are 8 species of Acrocephalus warblers, generally called “reed warblers”, in Thailand. They can be divided into 2 main groups, the large and the small sized reed warblers. Only 2 species are considered as large reed warblers; the Oriental Reed Warbler and the Clamorous Reed Warbler. These two are approximately 20 cm in length or about the size of a bulbul. The latter is an extremely rare vagrant OR a highly overlooked species in Thailand with very few accepted records, while the former is the commonest and most widespread reed warbler in the country. The identification of these two species is extremely challenging (definitely more challenging than what seems on the guide books!).


Clamorous Reed Warbler is a rare vagrant or seriously overlooked species in Thailand.


It resembles Oriental Reed Warbler in almost every aspect except for the slightly slimmer bill and shorter primary projections.


Supercilium is often weaker than in Oriental and most individuals lack whitish tail tips (though can appear in some odd birds)


At a glance, the Clamorous Reed Warbler looks slimmer (and sometimes longer)-billed and shorter-winged than Oriental Reed Warbler


Note short primary projections and the lack of whitish tail tips

I find the most reliable characteristics which are useful for field identification between Oriental and Clamorous Reed Warbler include bill shape and the length of primary projections. Clamorous often strikes as being a large reed warbler with very slender and pointed bill, whereas Oriental has a noticeably thicker and stronger bill. Primary projections are also shorter and less pointed in Clamorous than in Oriental. Most Clamorous Reed Warblers also lack the whitish tips to tail feathers even in fresh plumage, but some odd birds can have this characteristic similar to Oriental, so it’s probably not as reliable as the former two characteristics.


Among the small-sized reed warblers, Black-browed Reed Warbler is the commonest species.


It’s about the same size and at times can resemble a Phylloscopus warbler like Dusky Warbler or Radde’s Warbler.


Most of the time, the black eyebrows are thick and obvious enough to separate it from other similar species.


But sometimes the black eyebrow can appear faint and thin.


Often shows dark tip to lower mandible throughout winter


Worn individual can appear very pale sandy-brown

So what about the other 6 species of reed warblers in Thailand? They are all small-sized, approximately about the same size as a sparrow, or just a little larger than most Phylloscopus warblers. The commonest and most widespread species among these small-sized reed warblers is the Black-browed Reed Warbler.

With a prominent black eyebrow over the pale supercilium, you might think that it’s always straightforward to identify this species. Most of the time, it is indeed, but every once in a while, you come across odd individuals that look like it might not be a Black-browed Reed Warbler.


Manchurian Reed Warbler is listed as Vulnerable by the IUCN Red List. I photographed this bird in my local patch in Mae Taeng, Chiang Mai on 18 September 2004. It is still by far the only record of this species in the north.


Structurally, it looks longer-billed and longer-tailed than Black-browed Reed Warbler


Plumage is often warm rufous-brown throughout winter. Note different structure compared to Black-browed.



Very prominent supercilium which gets narrower behind the eye and thin black eyebrow


Lack dark tip to lower mandible during winter

The species that is mostly confused with Black-browed Reed Warbler is the globally threatened Manchurian Reed Warbler (or White-browed Reed Warbler by BirdLife). It is a  range-restricted breeder in China that winters in South-East Asia. In Thailand, it is known to be a passage migrant in northern and central parts of the country and spend the winter along the eastern coast of southern Thailand. Recently, it was found to be wintering in Malaysia and Cambodia as well.

When compared to Black-browed, the Manchurian Reed Warbler generally has a different structure by having longer tail and longer bill. The lower mandible also lacks dark tip during winter unlike in Black-browed. The dark bill tip will only develop in spring and summer. Overall plumage is also warmer and more rufous-tinged similar to Paddyfield Warbler, which was once treated as conspecific. The black eyebrow is often faint and thin with the pale supercilium being narrower at rear unlike in Black-browed Reed Warbler which gets broader behind the eye.

Note: Beware that some Black-browed Reed Warblers can also show faint/thin black eyebrows too. More photos and identification notes on Manchurian/Black-browed Reed Warblers can be read from Dave Bakewell’s post here.


Paddyfield Warbler is a rare winter visitor to small areas of northern Thailand.


This adult bird was ringed at Nam Kham Nature Reserve in February 2014 and was found to be a regular visitor at the Rubythroat Hide in the winter of 2015/2016.



Structurally resembles Black-browed Reed Warbler. Bill is rather short and shows prominent dark tip to lower mandible throughout winter.


Plumage is often warm rufescent-brown with rather short primary projection

Things get even more confusing with the small-sized reed warblers that lack black eyebrows. Let’s start with the Paddyfield Warbler, a bird that is widespread across Europe and Asia but is a rare winter visitor to Thailand. Once it was treated as the same species as the Manchurian Reed Warbler and it was no surprise. They actually share many similarities like warm rufescent-brown plumage and very similar wing formula and length of primary projections. Most Paddyfield Warblers show hints of dark eyebrow over the pale supercilium too, but never as pronounced as in Manchurian/Black-browed Reed Warblers. However, unlike in Manchurian Reed Warbler, the Paddyfield Warbler always shows dark tip to lower mandible throughout winter. The bill is also shorter and more pointy at tip than in Manchurian. In Thailand, it can only be found at several locations in northern part of the country including Nam Kham Nature Reserve in Chiang Rai where these photos were taken.


Blunt-winged Warbler is one of the trickiest birds to see and to identify.


It’s one the small-sized reed warblers that lack any trace of the dark eyebrow.


I probably wouldn’t be able to identify this bird without this lucky, even though blurry, flight shot that shows the wing formula.



Note how P1 is obviously longer than primary covert


Generally, it’s a long-tailed reed warbler with short supercilium.

The most challenging group of all reed warblers, and probably all Little Brown Jobs in Thailand, is the small-sized Acrocephalus warbler without dark eyebrows. There are 3 species in this group for Thailand; the Blunt-winged Warbler, Blyth’s Reed Warbler and Large-billed Reed Warbler. All three species share some very similar characteristics including the lack of dark eyebrow, longish bill and rather weak supercilium making them look quite plain-faced.

The commonest and most widespread species among the three is the Blunt-winged Warbler. It winters in wetlands throughout northern and central Thailand. Despite its abundance, it’s never easy to find one because of its extremely secretive behaviour. Even if you finally manage to see one, the bigger question is how to identify it! It’s almost impossible to identify these small-sized and plain-faced reed warblers without seeing the wing formulae.


Left: Blyth’s Reed Warbler; Right: Blunt-winged Warbler


Note the short and blunt primary projections as suggested by the name in Blunt-winged Warbler (left) compared to Blyth’s Reed Warbler (right).


The long P1 which extends beyond primary coverts is another main ID feature for Blunt-winged Warbler.


Blyth’s Reed Warbler is a rare winter visitor in Thailand. Note the much shorter P1 which doesn’t extend beyond primary coverts and longer and more pointed primary projections than in Blunt-winged Warbler.


Primary projections are longer and more pointed than in Blunt-winged Warbler.


Blyth’s Reed Wabler (left) tends to have colder and often more grey-tinged plumage than in Blunt-winged Warbler (right). The supercilium is also more obscured in Blyth’s Reed Warbler.


Blunt-winged Warbler in profile; note rather warm brown plumage and short but distinct supercilium.


Blyth’s Reed Warbler in profile; note cold greyish-brown plumage and less prominent supercilium


When seen in the field, Blyth’s Reed Warbler often has a long-billed and short-tailed impression.

The Blyth’s Reed Warbler is a rare winter visitor that has only been recorded several times at 2 different locations in Thailand; i.e. Nam Kham Nature Reserve in Chiang Rai and Bung Boraphet in Nakhon Sawan. Compared to the Blunt-winged Warbler, it generally has colder and more greyish-tinged plumage with much longer primary projections and slightly shorter tail. Its P1 is also shorter and doesn’t markedly extend beyond primary coverts unlike in Blunt-winged Warbler. It also usually prefers dryer habitats like shrubs and forest edge near wetlands, while Blunt-winged Warbler is a strictly wetland species that can be found only in reed beds.

Finally, the most challenging identification among all reed warblers is between the Blyth’s and Large-billed Reed Warbler. The Large-billed Reed Warbler is an extremely rare and little known species which has only been recently rediscovered in 2006 by Philip Round at Laem Phak Bia in Phetchaburi and followed by another record from Nam Kham Nature Reserve in 2008. It has also been recorded several times at Bung Boraphet afterwards. Generally, it has longer bill and warmer tone to the plumage than in Blyth’s Reed Warbler, but these two species can overlap in almost every morphological aspect. There was even a bird caught at Nam Kham Nature Reserve that couldn’t be identified even in hand, and DNA test was required. In the end, it turned out to be a Blyth’s Reed Warbler. Because of all the difficulties, I’m not going to touch on how to identify these two in the field and I’ll leave this post with a photo of a Large-billed Reed Warbler from Nam Kham Nature Reserve instead.


The second record of Large-billed Reed Warbler in Thailand from Nam Kham Nature Reserve. Photo by Woraphot Bunkhwamdi.

Kloss’s Leaf Warbler at Khao Yai

It’s been more than 2 months since my last blog post. I’ve been very busy with many things but should be able to dedicate more time to this blog soon. Anyway, this morning Wichyanan Limparungpatthanakij, Ingkayut Sa-ar and I went up to Khao Kheow checkpoint, the highest accessible point in Khao Yai National park to seek one of the least known resident Phylloscopus warblers in Thailand, the Kloss’s Leaf Warbler (P.ogilviegranti), of which Ingkayut recently found just around the checkpoint.


Habitat looked similar to hill evergreen forest that I’m familiar with in northern Thailand.


View from the view point; a couple of Great Hornbills were heard but not seen

We arrived at the checkpoint around 7AM. The weather was brilliant. The forest seemed lush against bright blue sky and warm morning light… but it was strangely SILENT. We almost didn’t hear or see any bird along the way up to the checkpoint. As we arrived, a Barred Cuckoo Dove was heard cooing deep in the forest along with a Mountain Imperial Pigeon.

After a while, we spotted a mixed species flock which seemed interesting and might contain our main target, the leaf warbler, but turned out it didn’t. We wandered fruitlessly around the checkpoint for about half an hour. Finally, Ingkayut and I heard a Phylloscopus leaf warbler singing from roadside forest. We tried but couldn’t locate the bird. It took us another long while to finally hear, probably, a different bird.


Kloss’s Leaf Warbler (most likely subspecies P. ogilviegranti intensior)

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Check out the undertail pattern! I’ve never seen such pattern before. Looks intermediate between Davison’s and Blyth’s Leaf Warbler.


Note faint yellowish wash on underparts


Tail pattern when spread

We had to use playback in order to see the bird, otherwise it wouldn’t come out to visibility. Interestingly, the bird didn’t respond so much to the song of P. ogilviegranti that we had but responded more to the song of P. davisoni. We also got some recordings of the song while the bird was singing up close. However, songs of both species sound identical to our ears but we might see some differences when analysed in sonograms.


Like other birds around the checkpoint, the Kloss’s Leaf Warbler also enjoyed the high concentration of moths and other insects that were attracted by nightlights from the checkpoint.

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It was very actively singing.


There are about 27 species of Phylloscopus warblers in Thailand. Only 5 of them are resident! 3 out of 5 are found in northern Thailand, i.e.Ashy-throated Warbler, Davison’s Leaf Warbler and Blyth’s Leaf Warbler, while Kloss’s Leaf Warbler is a very range-restricted species of north-east and south-east. The last one is Mountain Leaf Warbler which can only be found on high mountains in the southernmost part of the country.

Among these resident Phylloscopus warblers, Kloss’s is the least known taxon. Khao Yai is by far the most accessible location to see this species, even though it’s proved to be scarce. Another place where Kloss’s Leaf Warbler is known to occur and even said to be common is Khao Soi Dao which is way more difficult to access. Because of this, we felt blessed to have observe the bird so well and obtained some photos and voice recordings.


Adult Dark-sided Flycatcher (ssp. sibirica), the second record for this autumn passage



Another shot showing the distinctive undertail pattern


The bird liked to hang upside down searching for insects under branches and twigs but didn’t show any nuthatch-like behaviour as exhibited so strongly in Claudia’s/Hartert’s group.


Showing faint yellowish centre to belly, a bit more pronounced than in Davison’s

After seeing the bird and checking the photos that I took, several identification features can be summarised as follow;

  • very distinctive undertail pattern; sort of intermediate between Davison’s and Blyth’s
  • habitually more similar to Davison’s than Claudia’s/Hartert’s as it mostly sticks smaller branches and twigs rather than staying close to major trunks; also didn’t show any nuthatch-like behaviour
  • relatively more yellow on centre of belly than Davison’s; otherwise, other than undertail pattern, very marginally different
From left to right: Davison’s, Kloss’s, Blyth’s, Claudia’s and Hartert’s

From left to right: Davison’s, Kloss’s, Blyth’s, Claudia’s and Hartert’s

But the easiest way to identify is to see the undertail pattern! Finally, I have a complete collection of undertail view for each member of this complex in Thailand. Ranging from the one with most white on undertail (Davison’s on the far left) to the one with least white (Hartert’s on the far right), the image above should give you some idea of where to look when encountered with these birds.

Blyth’s & Davison’s Leaf Warblers at Doi Inthanon

On the weekend of 7-8 February, I joined the annual Doi Inthanon Bird Census held by Lanna Bird and Nature Conservation Club. The place is particularly good for leaf warbler lovers like me since 3 species (as far as we know) can be seen here easily. These include the range-restricted resident Blyth’s Leaf Warbler (Phylloscopus reguloides), the more widespread resident Davison’s Leaf Warbler (P. davisoni) and the widespread winter migrant Claudia’s Leaf Warbler (P. claudiae). During this recent trip, I observed all 3 species at different altitude of Doi Inthanon and could particularly get good images of the Blyth’s Leaf Warbler.


Blyth’s Leaf Warbler (presumably subspecies ticehursti)


Davison’s Leaf Warbler (formerly called White-tailed Leaf Warbler)

I’ve written a series of how to identify this Blyth’s/White-tailed Leaf Warbler complex which can be access here. In general, Davison’s has more yellow hue to its plumage than Blyth’s and Claudia’s, particularly on supercilium, face and median crown stripe. However, this can be very variable. The best way is to check for the undertail pattern, of which Davison’s shows completely white inner web to the outermost pair of tail feathers. Blyth’s and Claudia’s are almost identical plumage-wise. Unlike Davison’s, both species show grey undertail with thin white edge to the inner web of outer tail feathers with Blyth’s having more white than Claudia’s.


Undertail pattern of Blyth’s Leaf Warbler (same individual as above)


Undertail pattern of Davison’s Leaf Warbler (same individual as above)

At Doi Inthanon, Davison’s Leaf Warbler can be found throughout a wide range of altitude from ca. 1,000 m to the highest summit (2,565 m above sea level). Claudia’s Leaf Warbler can also be found through a wide range of altitude from lower foothills to at least about 1,500 m above sea level. So far, I still haven’t seen this species around the summit. On the other hand, Blyth’s Leaf Warbler is almost exclusively found above 2,000 m above sea level, but might move down to lower altitude (ca. 1,500 m) in winter (see this post).


Davison’s Leaf Warbler with nesting material


It didn’t show any left-right wing flicking behaviour exhibited in nesting Blyth’s Leaf Warbler. Instead, it rapidly flicked both wings constantly.

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The plumage looks particularly yellowish in strong light.


Note the undertail pattern


On the morning of Feb 7th, I visited Doi Pha Tang area (ca. 1,300 m above sea level) and found a nesting pair of Davison’s Leaf Warblers. They were busy building a nest located on a slope right on the roadside. The nest was only about 1 ft. above the ground but was well concealed by grass and fallen leaves. This is probably the earliest nesting record of this species for me. Compare to this nest I found at Doi Lang in March.


Blyth’s Leaf Warbler generally has less yellow tone to the plumage.


First time for me observing a displaying Blyth’s Leaf Warbler. The bird was whirring its wings and puffing up its crown feathers while singing actively.



Even though Blyth’s Leaf Warbler doesn’t share the ‘nuthatching’ behaviour in the same degree as in Claudia’s and Hartert’s Leaf Warbler, it appears to favour hanging vertically while foraging through small branches and vines.

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Sometimes it shares the same impression while foraging as in Claudia’s and Hartert’s, i.e. stretching its head to look out for food.


Blyth’s Leaf Warbler with insect in its mouth.


Undertail pattern confirming the identity

At the summit, there seemed to be more Blyth’s Leaf Warblers than Davison’s, which made me feel strange because I remember visiting in rainy season and couldn’t locate any Blyth’s Leaf Warbler. I also started to be able to recognise the songs of Blyth’s and Davison’s Leaf Warbler. Throughout the morning, I heard and observed many Blyth’s Leaf Warblers singing in the summit trail. The song of Blyth’s seems to have clearer notes and less slurred than Davison’s.


Blyth’s Leaf Warbler from the summit trail


Stretching to look for food



The median crown stripe is generally much less yellowish than in Davison’s.



Blyth’s Leaf Warbler singing

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Sometimes it also clings on vines.


Looking for food



Clean greyish median crown stripe


Showing the undertail pattern

There’s a particularly tame pair of Blyth’s Leaf Warblers around the entrance of the summit trail boardwalk. They might be looking for a nesting site since they were staying very close to the ground unlike most foraging Blyth’s Leaf Warblers that I’ve seen. Despite the very dim light inside the trail, I managed to get many close up shots of the birds.


Blyth’s Leaf Warbler



Showing undertail pattern


Before leaving the summit, I found another pair of Blyth’s Leaf Warblers close to the car park, so I could finally photograph this species in good light.


Showing wing formula


Sometimes it’s hard to see the real undertail pattern. A slight change of angle can totally distort the undertail pattern.


Sometimes the undertail of Blyth’s can even look similar to Davison’s, so take lots of photos and from many different angles.



Even in strong light, Blyth’s Leaf Warbler appears to be less yellowish than Davison’s Leaf Warbler.



More greyish median crown stripe and mantle


Showing the undertail pattern

Thailand’s First “Hartert’s Leaf Warbler”

On January 17th, a photographer found an unusual leaf warbler at Suan Rot Fai (Wachira Benjathat Park), a park located north of central Bangkok. According to him, he only took one picture of it (which I find very unusual) and the bird showed nuthatch-like behaviour. From that single photo, I suspected that it might be the nominate subspecies “goodsoni” of Hartert’s Leaf Warbler (Phylloscopus goodsoni) which has never been recorded in Thailand before. David Gandy, a local birder in Suan Rot Fai area, later relocated the bird on January 31st and took many more photos of it which helped confirm that it is most likely a “goodsoni” Hartert’s Leaf Warbler indeed.


Hartert’s Leaf Warbler (ssp. goodsoni) is a striking bird with bright yellow supercilium and contrasting crown stripes.


Another angle showing the highly contrasting crown stripes


It was mostly silent throughout the observation but briefly gave a few variably high pitched calls. Unfortunately, I wasn’t able to record the calls of it before it went silent again.


Apart from the supercilium, it has subtle yellow streaks on upper breast as well.



The undertail coverts are pale yellowish, slightly contrasting to the whiter belly.

I visited the park on Monday morning (2 February 2015) before going to work. Only about 5 minutes after arriving at the location where the bird was found, I could locate the bird foraging through the canopy in a nuthatch-like behaviour. There was also a highly vocal Grey-headed Canary-flycatcher foraging nearby which was a good thing since it helped me locate the leaf warbler easily. It is suspected that the canary-flycatcher follows the leaf warbler to catch the insects which are disturbed by the foraging movements of the leaf warbler.


My first view of the Hartert’s Leaf Warbler foraging through the main branches resembling Claudia’s Leaf Warbler or a nuthatch.


Showing underwing and wing formula


Climbing, looking, hopping


Showing undertail pattern; note very thin white edge to the inner web of outer tail feathers


The yellowness of plumage seemed to be very light-dependent. Even with bare eyes, the bird appeared variably yellowish depending on the light.


David sent some of his photos to seek opinions from Paul Leader, an expert on Asian Phylloscopus warblers, and here’s what he quoted.

“I would agree that this is nominate goodsoni. Within the ‘Blyth’s complex, only nominate goodsoni shows this degree of yellow and yellow streaking on the underparts, such that it resembles a washed out Sulphur-breasted Warbler more than other members of the Blyth’s complex. All of the other members of the complex have clean white underparts with limited yellow streaking (central breast/belly), and this includes Ph. g. fokhiensis.

However, the nuthatch-like behaviour is shared by other members of the complex, at least by claudiae, and therefore is not diagnostic.”


Showing the subtle yellow streaks on breast



The striking crown stripes


Again, the undertail pattern

I followed the bird from around 8.00-8.45 as it foraged through the main branches high up on tree tops and occasionally came down to just about 1.5 m above the ground and disappeared into the canopy again. It was totally an amazing observation and the bird didn’t seem to be particularly skittish, probably because I was the only one there. I guess it would stay around in the same area throughout the winter.


A confiding Radde’s Warbler


A female/immature Asian Paradise Flycatcher


Male White-rumped Shama

Apart from the leaf warbler, there were actually quite a good number of species in the area. There was one Radde’s Warbler which was unusually confiding. I also spotted a female/immature Asian Paradise Flycatcher, Black-naped Monarchs, a very confiding male White-rumped Shama, a pair of nesting Brown-throated Sunbirds, Yellow-browed Warbler, a fly-over Stork-billed Kingfisher and an Asian Barred Owlet. I guess I’ll be visiting this area of the park more often.

Doi Inthanon: 19-20 October 2014

On the night of October 19, Yann Muzika of The Wilderness Alternative and I drove up to Doi Inthanon, one of the most popular places for birding in northern Thailand. Our first mission was to look for the famous Brown Wood Owl family that was showing around the 2nd Checkpoint.


Adult Brown Wood Owl from the 2nd Checkpoint


It wasn’t all that easy. The wood owls usually come out to feed on horned beetles that only appear after the rain. It had been completely dry for several days before our arrive. There was no beetle around the checkpoint at all. Needless to say the wood owl wasn’t there. We tried using playbacks but still didn’t work. Instead, we heard several Mountain Scops-Owls calling, so we turned our attentions towards them. But the scops-owls weren’t easy neither. We had one bird perching in the open and really close for a second but couldn’t manage to take any photo even after that.

After more than an hour of struggling with the scops-owls, we walked back to the checkpoint and tried for the wood owl again. As earlier, there was no response, but then I decided to walk around a bit and was shocked to find one bird sitting really close to the road just a few metres from where we were standing. It might have been there all along but it made completely no sound. It sat there for about 5 minutes then flew out towards the checkpoint where I spotted another bird circling and disappearing into the forest.


A very obliging Black-throated Parrotbill at Km. 34.5




A Blyth’s/Claudia’s Leaf Warbler; note very thin white trailing edge to undertail feathers


Another photo showing the undertail pattern and median crown stripe


This Blyth’s/Claudia’s Leaf Warbler was attracted to the song of Blyth’s Leaf Warbler that I played, but it didn’t sing to respond. I observed it for several minutes and it didn’t show any trunk-climbing behaviour regularly exhibited by Claudia’s Leaf Warbler, so I concluded that it is most likely a Blyth’s Leaf Warbler. It’s the first time for me to see this species outside Doi Inthanon summit.

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Showing the undertail pattern; note thicker white trailing edge than the previous individual


After our successful night with the wood owls, we headed down to Muang Ang village at the foothill of Doi Inthanon to look for the globally threatened White-rumped Falcon but it was nowhere to be found. We then moved up to Km 34.5 trail instead and luckily, the place was very birdy. We encountered a big bird-wave consisting of a pair of male and female Clicking Shrike-babbler, Yunnan Fulvettas, Mountain Tailorbird, Grey-throated Babblers, Fire-breasted Flowerpeckers and lots of Phylloscopus warblers. But the best was undoubtedly a flock of about 10 Black-throated Parrotbills that was very responsive to the playback and gave us unusually good photographic opportunity.


Unknown butterfly found along the trail



Claudia’s Leaf Warbler, the trunk-climber!


Showing undertail pattern; note very thin white trailing edge

Most Phylloscopus warblers we found in the trail were the Blyth’s/Claudia’s/Davison’s Leaf Warbler group. For Davison’s, it wasn’t so difficult to identify since it has striking white undertail. However, it was much trickier when trying to identify Blyth’s and Claudia’s. I observed 1 bird which was most likely Blyth’s Leaf Warbler due to its behaviour and the width of white trailing edge to the undertail feather. It was the first time for me to see a Blyth’s Leaf Warbler outside the summit of Doi Inthanon.


Unidentified juvenile falcon, probably Amur Falcon or Eurasian Hobby


Blyth’s Leaf Warbler; most likely subspecies ‘assamensis’

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Much greyer median crown stripe than the abundant Davison’s Leaf Warbler



Note undertail pattern of the outer tail feathers


Showing white trailing edge to the inner web of tail feathers

We headed up to the highest summit around noon. It was still quite birdy when we arrived. Yann had a nice time with the extremely confiding White-browed Shortwings and a male Snowy-browed Flycatcher which are the regulars around the entrance of Ang Ka Nature Trail. I also had a chance to photograph a Blyth’s Leaf Warbler that was responding really well to the playback. Doi Inthanon summit is one of the very few places and the most accessible one in Thailand where this species is regularly found.


As usual, the Snowy-browed Flycatcher was extremely confiding.


Another very confiding bird, a Buff-barred Warbler from around the parking lot

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It must have been feeding on a lot of nectar. Note how the bill base is all covered up with pollen.



Bar-throated Minla was abundant as ever.


Even though it is a very common bird, I couldn’t resist taking photos of this group of Flavescent Bulbuls. They were just adorable.


Sadly, we could only bird just until a little after 12 o’clock because of the rain. However, we had a nice relaxing time while waiting in a coffee shop watching the birds that came to feed on bananas that the shop owner put out for them. These birds were really tame and we could take photos of them just with our phones. We drove down around 4pm and visited Muang Ang for the falcon again but still had no luck, so we continued down to Chiang Mai before heading to our next destination, Doi Ang Khang.

Doi Ang Khang: 12 October 2014

I made a solo journey to Doi Ang Khang on 12 October to check for winter migrants which should have already mostly arrived. I reached the foothill of Doi Ang Khang, around Ban Arunothai, just before sunrise. The place was as scenic and serene as ever.


The road to Ban Arunothai just before sunrise


The peaceful atmosphere around Doi Ang Khang foothill


Adult Crested Serpent Eagle (ssp. burmanicus)


Silhouette of a lone Rufous-winged Buzzard


They also like to perch together in a loose group.


Another view of a different Rufous-winged Buzzard



Either a juvenile or adult Changeable Hawk Eagle (ssp. limnaetus) in pale morph


Surprisingly, the morning was particularly good for raptors. I encountered 3 species of raptors just by the roadside. The first one was an adult Crested Serpent Eagle sitting on a dead tree top before sunrise. The second was the locally scarce Rufous-winged Buzzard which I found in total 7 birds in just one morning. The last species was the Changeable Hawk Eagle, which was found calling very loudly from the roadside. I’m not quite sure whether it was a juvenile or adult in pale morph. This was only the second time I found this species in this area.


More landscape shots along the way to Ban Arunothai

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A very blurry record shot of an adult Grey-backed Shrike, first for the season!


There were lots of Striated Swallows with a few Red-rumped Swallows in the mix at Ban Sin Chai.


A confiding Long-tailed Shrike (ssp. tricolor)



An unusually tame male Burmese Shrike

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The crown seems to be very dark slate-grey, almost looking concolorous with facial mask from some angles.


It was quite a birdy morning. I came across 2 Grey-backed Shrikes (1 adult and 1 juvenile) which was the first sighting for this season, and a very confiding male Burmese Shrike which has a striking dark crown. I’m still curious about which subspecies this one actually is. Read more about my speculation in this post.


It’s a rare occasion to see Striated Swallows perching against forest background!

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The resident subspecies stanfordi’ has bold streaks on underparts, particularly this individual.


Adult Red-rumped Swallow (ssp. japonica) is noticeably smaller with much thinner streaks.


Juvenile Red-rumped Swallow has even thinner and fainter streaking on the underparts with dull blackish crown and upperparts.



Showing the pale reddish rump

There were many Striated Swallows perching here and there. I also picked out a few Red-rumped Swallows in the mix too. Most of them were juveniles with at least 1 adult. When perching side by side, Red-rumped Swallows are noticeably smaller, being almost about the same size as Barn Swallow.


One of the many Black Bulbuls (ssp. concolor)


Female Ashy Minivet found mixing with a flock of Grey-chinned Minivets



The brightly coloured male Grey-chinned Minivet (ssp. rubrolimbatus)


Greenish Warbler was abundant!


Note the slightly greyer crown contrasting to the more olive mantle similar to Pale-legged/Sakhalin Leaf Warbler


But beware of the lighting condition. The same bird can appear to be totally different.


A relatively grey-crowned Yellow-browed Warbler



Hume’s Leaf Warbler (ssp. mandellii); note dark bill, legs and feet, greyish crown contrasting to mantle and smaller median covert bar. The ID was confirmed again by call.

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Note the white fringes on tertials

I came across a nice mixed flock of birds along the road including many Grey-chinned Minivets, 2 female Ashy Minivets, lots of Black, Mountain, Flavescent and Grey-eyed Bulbuls, Crested Finchbills and a nice pair of Blue-bearded Bee-eaters. There were also lots of Phylloscopus warblers everywhere. Most of them were the common Yellow-browed and Greenish Warblers but with some Claudia’s Leaf Warblers and a rather confiding Hume’s Leaf Warbler too!


I’m happy to get this photo showing the typical jizz for the Himalayan Swiftlet. Notice how long the wings are. The tail also looks longer than Germain’s Swiftlet.

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Rump patch can be quite variable though. This one shows a darkish rump patch looking almost concolourous with the back and uppertail coverts.


Most birds showed a quite contrasting pale rump patch but not as pale as in Germain’s Swiftlet.


But beware of the lighting condition. I think this bird has the same shade of rump patch as the previous one but strong light makes it look paler and more contrasting.


It’s interesting to see that many birds were moulting their tail feathers making the tail comes in various funny shapes.



A fork-tailed swift? No.


Never thought that it could resemble an Apus swift!

There were lots of swifts everywhere. I tried to focus mainly on taking photos of the Aerodramus swiftlets which should all be Himalayan Swiftlets. They all show quite a consistent jizz which is being noticeably larger with longer wings and tail than Germain’s Swiftlet of central and southern Thailand.


Cook’s Swift has a very dark blackish plumage and narrow rump patch.

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The tail is deeply forked hence the former named Fork-tailed Swift.


In good light, you can see the bold white scales on the underparts clearly.


Some birds looked a bit plainer because of the feather wear.

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Another species of swift that was regularly seen was the huge Cook’s Swift. It is a recently split species from what used to be called Fork-tailed Swift which has now split into 4 different species. Cook’s Swift is a very dark one, looking very plain blackish from above with the narrowest white rump patch. Dave Bakewell has a nice blog post on the identification of Cook’s and Pacific Swift which is a widespread winter migrant in SE Asia here.


A colourful male Fire-breasted Flowerpecker

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Not sure about the sex and subspecies of this White Wagtail. The black breast patch looks good for breeding male leucopsis but it has grey back, so it might be a female breeding instead? The black rump and uppertail coverts rule out baicalensis.


It was interesting to see a flock of migrating Black Drongos flying overhead. This should be the subspecies D. m. cathoecus which is described to be the wintering race.


A very confiding juvenile Grey-backed Shrike


One of the two Buff-throated Warblers


Adult Mountain Hawk Eagle

Other interesting birds seen during the afternoon included a nice pair of Buff-throated Warblers which was the first sighting of the season and a huge adult Mountain Hawk Eagle which glided by at eye level. A beautiful male Mrs. Gould’s Sunbird also came to feed on flowering tree and gave a nice close up view too, but the highlight of the day came during the late afternoon just when I was driving back home, a nice 30+ flock of Grey-headed Parrotbills just by the roadside! The birds gave exceptional views while moving along the roadside before disappearing into the dense forest.


Despite its large size, Grey-headed Parrotbill is probably the trickiest one to see and photograph well.

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First time for me getting 2 birds in one frame.


They were also quite curious!


Nam Kham Nature Reserve: 28-29 March 2014

On the evening of March 28 saw me arriving at Nam Kham Nature Reserve in Chiang Saen, Chiang Rai Province with my friends who are also bird ringers. They had to prepare poles and nets for the following morning, so I went into one of the hides to see if there’s any bird at the pool made for birds to come and bathe. To my surprise, as I stepped into the hide, the rare Chestnut-crowned Bush Warbler was already bathing, as well as a male Siberian Rubythroat. They quickly flew into the bush as they noticed me but came out shortly afterwards.


The Chestnut-crowned Bush Warbler came down to the pool 3 times until it got completely dark, but I could only get a few ok-ish shots. This is a rare and quite mysterious species that overwinters in northern Thailand. We only knew that it spends the winter in lowland reed beds just a few years back when Nam Kham was established. On the other hand, it moves up to high montane forest to breeding during breeding season.

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While the bush warbler was away, I was entertained by a family group of the colourful Chestnut-capped Babbler. Two parent birds and two juveniles came to enjoy evening bath for more than 10 minutes. Both of the parents were ringed just like the bush warbler and most birds here. Another bird which came to the pool was the lovely Baikal Bush Warbler, but it was already too dark for me to get any good shot.


A ruin at the entrance from the main road to Nam Kham Nature Reserve


Chestnut-capped Babbler looking really smart when seen up close


Yellow-bellied Prinia was particularly brightly coloured.


Male Siberian Rubythroat


The throat somehow reminds me of an almost ripe strawberry.

On the following morning, I joined a ringing session where we caught some really nice birds. The first one that I saw was a smart adult Chestnut-capped Babbler followed by a very brightly coloured Yellow-bellied Prinia. A beautiful male Siberian Rubythroat was also caught as well.


Blyth’s Reed Warbler, a Thai rarity and a lifer for me


Long primary projection relative to the similar Blunt-winged Warbler


Wing formula of Blyth’s Reed Warbler


But the highlight of the session was a single Blyth’s Reed Warbler, one of the rare Acrocephalus warblers in Thailand. Few records have beeb reported from Nam Kham Nature Reserve and Bung Boraphet in Nakhon Sawan Province.


One of the two Blunt-winged Warblers caught on that morning


Blyth’s Reed Warbler (left) and Blunt-winged Warbler (right)


Blunt-winged Warbler (left) has shorter primary projection than Blyth’s Reed Warbler (right).


When compared closely, Blyth’s (left) shows paler and more rufous iris, while Blunt-winged (right) has a colder brown tone. However, iris colouration can be greatly varied.


Focusing on the Blunt-winged Warbler


Now focusing on the Blyth’s Reed Warbler

We also caught 2 Blunt-winged Warblers, a rather common but extremely difficult to see species, so we had a really nice opportunity to compare the two species closely together. The best way to distinguish the two is by looking at the primary projection. Blunt-winged Warbler has shorter primary projection than Blyth’s making the wings look shorter and rounder, hence the name Blunt-winged. Apart from the primary projection, I also noticed that the iris of the two species were slightly different; Blyth’s having a lighter and more rufous colouration than Blunt-winged which has a cold brown tone to it.


The same Blyth’s Reed Warbler after being released


At least the long primary projection is visible!

Since there had been no confirmed photo of Blyth’s Reed Warbler taken in Thailand in the wild, I prepared to take photos of it after being released. The above shots were already my best effort. Unfortunately some part of the bill is hidden in both shots but at least the long primary projection is still visible confirming that it is not a Blunt-winged nor Paddyfield Warbler.

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I then took a walk around the reed maze and came across 2 singing Acrocephalus warblers in tall reeds. Since one of them was so close, I tried recording the song using my iPhone and played back. Quite amazingly, despite the very low volume, the bird still responded and came out to perch on reed top for few seconds, enough for me to snap some shots before it flew out. One of the shots shows wing formula which seems to suggest that it’s a Blunt-winged Warbler (relatively long P1).

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Before leaving Nam Kham, I spent about an hour sitting in the hide waiting for birds to come and bathe. Only a Baikal Bush Warbler showed up briefly. I guess it was the same individual that showed up in the earlier evening. It was still in a non-breeding plumage, showing no sign of grey on breast nor dark lower mandible which are characteristics of breeding plumage.