Large Acrocephalus on Leyte, Philippines (1 Viewer)

Valéry Schollaert · Dec 1, 2017

Hi all,

I've published this photo as Acrocephalus orientalis on Wild Bird Photographers of the Philippines, but a member suggested, although not being sure, it might be a Acrocephalus stentoreus harterti, a subspecies I've not seen yet.

I'd be very interested by any comment on separating those 2 similar species.

Thanks.

Andy Adcock · Dec 1, 2017

I'd say personally that leg colour alone, would support your original ID. It has bluish feet and legs and this seems to be a common feature among images on Google, Blyth's has pinkish legs, if that's reliable

A

Valéry Schollaert · Dec 1, 2017

andyadcock said:
I'd say personally that leg colour alone, would support your original ID. It has bluish feet and legs and this seems to be a common feature among images on Google, Blyth's has pinkish legs, if that's reliable

A

Sorry Andy, I wrongly wrote "dumetorum" instead of "stentoreus", we are talking about local Clamorous Reed W. and wintering Oriental Reed W.

Bryon Wright · Dec 1, 2017

Hi all,
bill and facial pattern, tail shape clearly show this to be orientalis not stentoreus. It can appear slightly smaller and greyer than great reed warbler and thus perhaps closer to some stentoreus.

Grahame Walbridge · Dec 1, 2017

IMO an Oriental Reed Warbler based mainly on bill structure; thick and with a noticeably curved culmen distally, appearing slightly decurved. Also note, in the second image, there appear to be pale tips to the rectrices which another plus feature although there is no streaking visible on the underparts. Leg colour is good but within the range of CRW. There should be a clear difference in pp between the two but the angle of the second shot does not allow accurate assessment.

Clamorous Reed A.s.harterti for comparison. Scroll down. Note differences in bill structure, leg colour and pp. Also appears longer-tailed though does show indistinct paler tips, possibly as a result of wear.

https://tonjiandsylviasbirdlist.smugmug.com/keyword/wbcp;philippines/

Grahame

Valéry Schollaert · Dec 1, 2017

thanks for your help guys, much appreciated! :t:

There should be a clear difference in pp between the two but the angle of the second shot does not allow accurate assessment.

Sorry, you know how are the reed warblers, they decide, not you!

I've another angle here, may be better to guess the wing structure although quality is poor, if it can help a bit...

I'm glad with your conclusions anyway!

Cheers B

Valéry Schollaert · Dec 1, 2017

Also note, in the second image, there appear to be pale tips to the rectrices which another plus feature

Well, this is confirmed on this horrible image. Is that somehow a diagnostic feature of O. R. W. ?

Bryon Wright · Dec 1, 2017

Valéry,
orientalis again.

Grahame Walbridge · Dec 1, 2017

Bryon Wright said:
Valéry,
orientalis again.

Same bird Bryon.

Still unable to assess pp., prefer not to guess!

Regarding pale tips to the rectrices it is a good feature for ORW but doubtfully diagnostic IMO. There is also a suggestion of paler tips to the gc's in the second image but its not visible in the lower image.

http://orientalbirdimages.org/search.php?Bird_Image_ID=112945&Bird_ID=1758&Bird_Family_ID=&Location=

Grahame

CARERY · Dec 1, 2017

Grahame Walbridge said:
There should be a clear difference in pp between the two but the angle of the second shot does not allow accurate assessment.

Grahame

I agree it is difficult to estimate the pp (only chance at second picture of post 1 IMO). But as it is such a crucial feature I'm not willing to give up that easily

. If carefully checking for the pale fringes of the three tertials to me it seems to be clear where the longest tertial ends. There is a small step. Which would mean the pp is too short for Acrocephalus orientalis, am I wrong? The other features mentioned seem to be less solid, no? Question is if you can agree with my chain of evidence |^|

Valéry Schollaert · Dec 1, 2017

CARERY said:
I agree it is difficult to estimate the pp (only chance at second picture of post 1 IMO). But as it is such a crucial feature I'm not willing to give up that easily . If carefully checking for the pale fringes of the three tertials to me it seems to be clear where the longest tertial ends. There is a small step. Which would mean the pp is too short for Acrocephalus orientalis, am I wrong? The other features mentioned seem to be less solid, no? Question is if you can agree with my chain of evidence |^|

I cannot give the proportion of pp exactly, but I noticed (visible on photo 2 indeed) that the wing is pointed, while all photos of Clamorous R. W. show rounded tip of wing...

Valéry Schollaert · Dec 6, 2017

Hi guys,

I went back to the same place and found the same bird again. Any more thoughts with those 2 additional images?

I have to add that compared to available recordings on XenoCanto, both song and calls matches much more Oriental R. W. to me that Clamorous.

Graham, and you seemed to have changed your mind (in private messages), on which camp are you now with those?

Thanks

Bryon Wright · Dec 6, 2017

Warbler id

Hi all,
another ORW.
Obviously CRW. would have the shortest wing length but it is still a slightly different rubic from that of separating CRW/GRW.
The short outer tail feathers of ORW during moult, together with the shorter PP. of ORW relative to GRW, invites confusion.
The veracity of many CRW's records in this region have always been in doubt. For anybody visiting the region fresh IY. orientalis are not that difficult, they are widespread, sometimes, also inhabiting mangroves and when fresh have a tawny rump. Being very territorial, their call is a loud and frequent acro sound like the static on those old policeman's personal radios!

CARERY · Dec 6, 2017

The last pictures show a really very short-winged bird! This surely can't be an Oriental Reed Warbler. But how can you be certain it is the same bird as some days ago?

FWIW just found out that HBW alive considers all A. stentoreus ssp. occuring on SE-Asian island to actually belong to Australasian Reed Warbler A. australis (https://www.hbw.com/species/australasian-reed-warbler-acrocephalus-australis. This is obviously based on morphologicalical and vocal evidence... Hmm, interesting development!

Valery, you mentioned that the calls and songs sounded more similar to Oriental? Did you make sure only to listen to ssp. harterti?

CARERY · Dec 6, 2017

Bryon Wright said:
Hi all,
another ORW.
Obviously CRW. would have the shortest wing length but it is still a slightly different rubic from that of separating CRW/GRW.
The short outer tail feathers of ORW during moult, together with the shorter PP. of ORW relative to GRW, invites confusion.
The veracity of many CRW's records in this region have always been in doubt. For anybody visiting the region fresh IY. orientalis are not that difficult, they are widespread, sometimes, also inhabiting mangroves and when fresh have a tawny rump. Being very territorial, their call is a loud and frequent acro sound like the static on those old policeman's personal radios!

Bryon, are you sure we are looking at the same bird? I took the liberty to crop and enhance one photo a little and marked the pp. This is way too short for any Oriental Reed.
Possibly I'm getting you wrong, but are you suggesting the occurence of Clamorous Reed (or Australasian Reed if following HBW) is doubtful on the Phillippines?

Valéry Schollaert · Dec 6, 2017

CARERY said:
The last pictures show a really very short-winged bird! This surely can't be an Oriental Reed Warbler. But how can you be certain it is the same bird as some days ago?

FWIW just found out that HBW alive considers all A. stentoreus ssp. occuring on SE-Asian island to actually belong to Australasian Reed Warbler A. australis (https://www.hbw.com/species/australasian-reed-warbler-acrocephalus-australis. This is obviously based on morphologicalical and vocal evidence... Hmm, interesting development!

Valery, you mentioned that the calls and songs sounded more similar to Oriental? Did you make sure only to listen to ssp. harterti?

For the song, I compared both properly with the right subspecies, I was already fairly sure before seeing the bird last time. Today, I heard the call first time. As Bryon says, it is quite unique. I didn't find call of harterti online, I compared with Indian ssp, but the difference is huge.

Clamorous Reed Warbler is fairly common on Leyte, I hear it regularly in long reeds near my place, but not yet in my camera though. I'd love to see one harterti properly to compare with our op bird that is for me O. R. W, but not 100% because of Desmond Allen doubts.

I asked him with the new photos and call, I wait for his reply

I didn't check HBW, but I'm not surprised. Desmond told me harterti is "totally different" than Clamorous R. W. from mainland S.E. Asia.

Valéry Schollaert · Dec 6, 2017

Bryon Wright said:
Hi all,
another ORW.
Obviously CRW. would have the shortest wing length but it is still a slightly different rubic from that of separating CRW/GRW.
The short outer tail feathers of ORW during moult, together with the shorter PP. of ORW relative to GRW, invites confusion.
The veracity of many CRW's records in this region have always been in doubt. For anybody visiting the region fresh IY. orientalis are not that difficult, they are widespread, sometimes, also inhabiting mangroves and when fresh have a tawny rump. Being very territorial, their call is a loud and frequent acro sound like the static on those old policeman's personal radios!

Thank you so much Bryon, upper-tail coverts are strikingly tawny, contrasting with the rest. Is that somehow diagnostic? How are UTC in harterti?

Bryon Wright · Dec 8, 2017

Hi all,
Do not know anything about harterti rump colour but Hartert was very meticulous in his other descriptions. In a wider context, even skins in collections have been queried right up to recent times.

Valéry Schollaert · Dec 26, 2017

Hi all and merry Christmas, happy New Year,

I went back at the little square of reeds in the middle of rice fields where was my op warbler for the first time yesterday since the last typhoon that brought strong winds and very heavy rains. The area has somehow changed: the suitable habitat for reed warblers has reduced and all around is flooded, so I cannot reach that close anymore.

The square now holds at least 4 large Acrocephalus warblers. The op bird is still there, and 3 new birds, evidently local harterti have come. Now, with direct comparison of size, voice and plumage, I can confidently confirm my op bird to be Oriental Reed Warbler. Compared to it, local Clamorous/Australasian (soon Philippines R.W.?) harterti show: smaller bill, smaller size, less contrasted rump, no buff tip of tail, shorter pp. The call is strikingly different.

Here is the best photo I could do with the distance.

I with to thank Desmond Allen who made me discover how difficult is the identification of those 2 species, and all members who commented here.

Cheers

NB: this photo show harterti to compare, if I didn't make it clear

CARERY · Dec 27, 2017

Weeks have passed since you observed the op bird. I wonder how you can be sure than one of the four birds present now is still the the very same individual? Curious...

I'm still convinced that your op bird is no Oriental Reed but a Clamorous. Possibly a ssp. that is migratory and not the local harterti?

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