Experience in Pale-legged V.S. Sakhalin Leaf Warbler in 2017 Autumn

Phylloscopus is always one of our favorite birds, because they are cute, and extremely challenging for a safe ID in most of the cases, especially true for some 'species complex', like Arctic Warbler complex, and today's topic: Pale-legged Leaf Warbler Phylloscopus tenellipes v.s. Sakhalin Leaf Warbler Phylloscopus borealoides.

We have both species in Hong Kong but the status of the latter one is more uncertain. In the past, Sakhalin Leaf Warbler is mainly identified by the timing and showing longer primary projection, which both features are much overlapped with Pale-legged Leaf Warbler. So only song and DNA analysis are thought to be the most reliable features to tell the species. But in fact, call maybe another one, and the summary of our experience in this Autumn as here, as we are lazy birders, the information should not be conclusive.

20/9/2017 Wetland Park
Pale-legged / Sakhalin Leaf Warbler X1
A bird very responsive to Sakhalin song, but sadly it did not call or sing, leaving us an unsolved question.

20/9/2017 Wetland Park
Pale-legged Leaf Warbler X1
ID by call

22/9/2017 Wetland Park
Pale-legged Leaf Warbler X4
ID by call

25/9/2017 Wetland Park
Pale-legged Leaf Warbler X1
ID by call

26/9/2017 Wetland Park
Pale-legged Leaf Warbler X1
ID by call

28/9/2017 Wetland Park
Pale-legged Leaf Warbler X1
ID by call

1/10/2017 Wetland Park
Pale-legged Leaf Warbler X2
ID by call

2/10/2017 Wetland Park
Pale-legged Leaf Warbler X1
ID by call

4/10/2017 Wetland Park
Pale-legged Leaf Warbler X1
ID by call

25/10/2017 Wetland Park
Pale-legged / Sakhalin Leaf Warbler X1
No call no song no ID

7/11/2017 Wetland Park
Sakhalin Leaf Warbler X1
ID by call

10/11/2017 Mount Davis
Pale-legged Leaf Warbler X1
ID by call


SO, from our past experience, listening a Pale-legged call is much commoner, which may mean Pale-legged Leaf is much commoner than Sakhalin in Hong Kong. and one more thing, Sakhalin seems coming HK much later than Pale-legged but again, there is overlapping.

Anyway, how to tell from the call? here's the recording this Autumn.

First, a call ID as Pale-legged Leaf Warbler on 2 Oct.
http://www.xeno-canto.org/393390

Second, a call ID as Pale-legged Leaf Warbler on 10 Nov.
http://www.xeno-canto.org/392762


From sonogram, we can see the call is much above 5k Hz, and approaching nearly 6-7k.

Pale-legged Leaf Warbler

Pale-legged Leaf Warbler

Lets compare to the recordings for a Sakhalin Leaf Warbler on 7 Nov.

http://www.xeno-canto.org/391994
http://www.xeno-canto.org/391992

The sonograms show the call is below or near 5k Hz.

Sakhalin Leaf Warbler

Sakhalin Leaf Warbler

So we can tell the difference of the call, not just by sonograms but in fact by human ear too. Sakhalin Leaf Warbler's call is somehow similar to the one produced by Daurian Redstart Phoenicurus auroreus, We think.

How about appearance? We did not have any photos of (safe) Pale-legged Leaf Warbler, but some of the Sakhalin on 7 Nov, you can try check the OBI for comparison.

Sakhalin Leaf Warbler

Sakhalin Leaf Warbler

From the above, you can see the Sakhalin Leaf Warbler is showing:
1. Pink legs
2. Distinct supercilium
3. Two wingbars, with no contrasting between
4. A rather dark bill with yellow base and a whitish tip

These four features also fit Pale-legged Leaf Warbler, so we think the appearance may not help. For behavior, this Sakhalin did wag its tail, also shared by Pale-legged Leaf Warbler, but sometimes, this bird would forage in mid to upper canopy, which we seldom heard Pale-legged would do the same as suggested in other books.

Any conclusions? In fact no. But after checking some literature and a review on Xeno-canto, we think the call is a really reliable feature to separate this species complex, especially in winter or passing, when the birds do not sing. And as the status of Sakhalin Leaf Warbler in Hong Kong is still uncertain, it is always worth to have a look and listen plus record (!) when you see a Pink-legged Phylloscopus one day.

Some reference here, suggested to read:
http://www.shanghaibirding.com/2017/08/31/pale-sak-call/
http://confoley.com/site/wp-content/uploads/BirdingASIA-21-Sakhalin-Leaf-Warbler.pdf

A review of my HK birding life 13 - Upland Pipit Anthus sylvanus

Upland Pipit Anthus sylvanus

My final post of this review series, I want to end with the letter U. This monotypic pipit is a montane species and facing declination in HK. You haven't seen this bird yet, wish we will find a tamer one, take a better photo, together.

A review of my HK birding life 12 - Oriental Scops Owl Otus sunia

Oriental Scops Owl Otus sunia

In our birding life, not just daytime birding, but also at night. Not many owls species in Hong Kong, we have two scops owl, Collared Scops Owl is a very common residents, another one is Oriental Scops Owl, mainly passage migrants with occasional summer record. We will never forget the excitement when seeing an owl in a peaceful night.

A review of my HK birding life 11 - Yellow-browed Warbler Phylloscopus inornatus

Yellow-browed Warbler Phylloscopus inornatus

Another common HK species. I love Phylloscopus very much because of the challenge in identification. We watched. heard and took countless Yellow-browed warblers in 5 years and this photo I love the most, taken in Shek Kong, an extra gift when looking for the rosefinch.

A review of my HK birding life 10 - Eyebrowed Thrush Turdus obscurus

Eyebrowed Thrush Turdus obscurus

There are many Turdus species in Hong Kong, especially in winter, Eyebrowed Thrush is one of them. It is a very widespread and common winter visitor, and also passage migrant in HK. But surprisingly, we only managed to get a good shot until recent winter, in Feb 2016, of a first winter bird.

A review of my HK birding life 9 - Verditer Flycatcher Eumyias thalassinus

Verditer Flycatcher Eumyias thalassinus

On my birthday, i would take the the Verditer Flycatcher, a common but beautiful blue bird. My favorite blue.

A review of my HK birding life 8 - Oriental Plover Charadrius veredus

Oriental Plover Charadrius veredus

I love shorebirds, Oriental Plover is one of them. This species is a Least Concern species and a typical one using the East Asia - Australia flyway. In HK, they can only be found in a short period of time in spring and autumn, making twitching difficult. But we were lucky enough to look at two birds in close distance in one spring.

A review of my HK birding life 7 - Lanceolated Warbler Locustella lanceolata

Lanceolated Warbler Locustella lanceolata

Lanceolated Warbler is a widespread, Least Concern species and common passage migrant in Hong Kong. Its skulking behavior during migration and in wintering ground make us difficult to observe well. However, the birddom always give you surprise, by letting us to watch a friendly lancy in the heart of HK.

A review of my HK birding life 6 - Ijima's Leaf Warbler Phylloscopus ijimae

Ijima's Leaf Warbler Phylloscopus ijimae

This little bird is one of my favorite East Asian birds. It only breeds in some isolated islands of Japan and has a poorly known migration route. Because of this, it is suggested to be a Vulnerable species. We tried several times on Po Toi for getting good photos, but still failed. So, We needa go to Miyakejima to try again and also the endemic birds there.

A review of my HK birding life 5 - Yellow-breasted Bunting Emberiza aureola

Yellow-breasted Bunting Emberiza aureola

Like the rustic bunting, Yellow-breasted Buntings are facing the same fate, but their situation is even worse. They were once used to be a very common bunting, breeding across the whole Eurasia and even to Hokkaido, but now, they are undergoing a 90% population decline mainly due to over-exploitation, especially hunted for food in China, and hence, they are now listed as Endangered species in the IUCN red list. In the last five year, we have tried to take as many good photos as we can, but we still haven't seen a male in full-breeding plumage. Though, this non-breeding male can  always remind us of the importance of protection before they are totally extinct.

A review of my HK birding life 4 - Rustic Bunting Emberiza rustica

Rustic Bunting Emberiza rustica

Rustic Bunting is used to be a widespread and common species, like tree sparrow.But now this bird is facing rapid population decline in both Europe and Asia mainly due to hunting and habitat change, so it is upgraded to a Vulnerable species according to the IUCN red list. Although we have recorded this species in HK for many times, we still could not stop our love and took more decent shots.

A review of my HK birding life 3 - Relict Gull Larus relictus

Relict Gull Larus relictus

This vulnerable gull is called a relict because it was long treated as a subspecies or hybrid of Mediterranean gull, until 1970s, it was known to be a distinct monotypic species. This is a classical example of how new species discovery can be easily overlooked. This rare gull only breeds in Northern China, Mongolia and Central Asia while the wintering ground is still incompletely understood. There are occasional records in Hong Kong, which I have missed several times, but finally, we were lucky to tick an immature bird few years ago.

A review of my HK birding life 2 - Oriental Stork Ciconia boyciana

Oriental Stork Ciconia boyciana

Another endangered species, which was used to be a regular winter visitor in Hong Kong. Similar to Siberian Crane, it is also threatened by habitat destruction. Five years ago, one bird came to Mai Po again, surprisingly in summer, and stayed for whole winter, so everyone could make an easy twitch.

A review of my HK birding life 1 - Siberian Crane Leucogeranus leucogeranus

Siberian Crane Leucogeranus leucogeranus

The most rarest crane in East Asia, formerly placed in genus Grus but now is more generally accepted as its own monotypic genus Leucogeranus. Nearly 90% of its global population winters in Poyang Lake, however, they are facing great stress due to habitat change and hence clarified as an Critically Endangered species in the IUCN Red List. There are two records in HK. And we were very lucky to get a shot of the long-wintering adult with its juvenile, which only stayed for 2-3 days in Mai Po.

The Cyornis Blue

Leaving this blog for more than a year, mainly because of my study. Now, as still during the unemployed period, I have more time and better start again and focusing more on bird ID.

In this Feb and March, two Cyornis species, Chinese Blue Flycatcher Cyornis glaucicomans and Hill Blue Flycatcher Cyornis banyumas were recorded in Hong Kong. I took the chance and manage to get some shots of both. The Chi Blue is quite elusive while the latter one is being fed, allowing me to take photos of reasonable quality.

Male Cyornis is usually in a combination of blue plus yellow and sometime causing problems in identification, while female is duller and much more troublesome. Luckily, the two we have recorded recently are first-winter male, and assuming adult plumage in this time of year.

Chinese Blue Flycatcher, note the brownish wing indicating this is a 1st winter bird

The key feature for separating from Hill Blue is mainly the throat. For Chi Blue, the yellow throat is more limited, showing a very narrow triangle and blue chin.

Chinese Blue Flycatcher

The Hill Blue also showing brownish wing, and pale tips on tertials.

  

Hill Blue Flycatcher

Hill Blue Flycatcher

Hill Blue Flycatcher

 The yellow throat of Hill Blue is wider and showing a yellow chin in most of the angles.

Hill Blue Flycatcher

Hill Blue Flycatcher

A comparison

Although both flycatchers are put on the latest HK checklist cat I, male Cyornis is a common pet species and many of the past records are treated as escaped birds. For the case of Hill Blue, the closest range is Guangxi and mainly non-migratory, under the subspecies whitei. Worn feather especially the tail can be observed in this bird, leaving us a question whether this bird is truly wild or not.

Hill Blue Flycatcher

And according to the recent studies, the Jungle Flycatcher is also grouped into the genus Cyornis, like this Brown-chested Jungle Flycatcher Cyornis brunneatus taken in mainland China few years ago.

Brown-chested Jungle Flycatcher