Large-billed Reed Warbler

@

Kanha National Park, Central India

A sure-site for the data-deficient species?

This page provides the details of a mystery Warbler observed by David Raju, a naturalist in Central India, from a bamboo thicket near Kanha National Park between 5^th April 2008 and till date (2^nd May 2008).

Summary: A confusing Warbler which was observed through out April near Kanha National Park, Central India by David Raju and his friends is slowly turning out to be none other than the elusive Large-billed Reed Warbler. From a set of 13 photographs and several field observations, all other similar species has been eliminated. However, confusing these Warblers are– one cant be sure unless one gets a specimen in hand (& perhaps confirm with DNA). This shall perhaps be the 5^th or 6^th time in history that this Warbler is recorded and second time in the field (others were all netted).

David has added some critical behavioural information of this species which could well be used to pop up more individuals. The key observations are

“sticks to the upper canopy and rarely coming down to feed”,

“fans its tail very often much similar to Fantail or Monarch flycatcher”

and seems to have a “preference to mango trees and bamboo clumps”

Full Story:

The first photo made during the first week of April 2008 by David was sent to me (Praveen) for confirmation labeled as Blyth’s Reed Warbler. The bird was believed to be nesting as it was using a particular bamboo clump during early morning and late evening. The picture was posted in delhibirdpix also. Initial feeler was that this could be a Clamarous Reed Warbler.

“Interesting! Certainly the picture is not good enough to id 100% but the supercilium looks too obvious behind the eye for a Blyth's Reed. There seems to be slight white at the tip of the tail and it looks very long-billed. Is he sure about the size? I think it could be a Clamorous Reed Warbler, which would explain the breeding. If he is convinced that it is not Clam Reed then it's very interesting and needs a very good set of photos …”

Mike Prince

However, David Raju, who is familiar with Clamarous Reed Warbler (from Vembanad Wetlands, Kerala) was sure of the size and he maintained that it was not a Clamarous. He also informed me (via phone) the following information.

à Calls of the bird are somewhat similar to Blyth’s Reed Warbler

à He could see a structure in the clumps, what he believes, is the nest of this bird.

à Meanwhile, he got hold of the sanctuary magazine with the observations of Large-billed Reed Warbler from Kolkota (by Sumit.K.Sen) and he seems to have observed in his bird “pointed tail feathers” and “fanning of the tail behaviour”.

By then, Mike has already brought in Bill Harvey, Philip D Round and Sumit K Sen in the loop and we were all waiting for the next set of photographs from David ; who is strung up in a far corner of Kanha N.P without a proper cell phone range and broadband/dial-up connectivity.

When the next set of three pictures arrived….

Warbler 200

…with the following information passed via phone

à There are about 5 individuals present in a set of bamboo clumps owned by the tour company for which David works (he is a naturalist). He believes all are of same species (Note: Each photo could have been
of a different individual).

à Apart from Blyth's Reed Warbler like chuck, one of the birds did produce once a small melodious song somewhat similar to that of Magpie Robin.

à He saw on several occasions when the bird fanned its tail.

à Species seems to skulk in the clumps and photography seems to be difficult, according to him (photos made with Nikon D80 + Sigma 300mm lens).

à He has seen a structure among the bamboo clumps which he believes is a nest. He has seen the bird enter the bamboo clumps during the dusk and come out of the clumps at dawn (5:50 AM). It has not been possible to check if the bird has laid eggs (clumps are thick and it is not possible to check it without disturbing the likely nest) - however, he has not seen the bird brooding during any time of the day.He has also not seen "nest-building" per-se. There are several other structures in the bamboo clumps, smaller ones, which are also likely nests - perhaps of the more common Plain Prinias.

à The bird is most active till 9AM and then active at dusk. He also saw the bird chasing away Brown Shrike & Plain Prinia near the structure which seemingly he believes is a nest

However, at least one of the photos (last one), clearly showed a Syke’s Warbler (!).

“think these are Sykes's Warblers. 'Better' proportioned than Blyth's Reed for example with shorter wings/longer tail (esp clear in Warbler-200), clear supercilium, wholly pale lower mandible and fleshy-coloured legs with greyish feet, plus white tips to the tail.

The tail fanning is interesting: not something I've heard of before but it could well be documented for other acro/hippo species. The nesting behaviour sounds much more like roosting than nesting. The song sounds like a bit of subsong which is to be expected at this time of year (I heard one this morning.)

Very interested in other people's opinions though. “

Mike Prince

“Agree with Mike. Structure doesn’t fit Large-billed or Clamorous. There doesn't seem to be any firm evidence that the "nest" is theirs. A group of migrant warblers singing will also often display. Indeed they may be pairing up.”

Bill Harvey

David Raju, though disappointed, was still not very convinced. He kept going after the bird as it was found quite near to where he was put up. Around third week of April, he sent me the following pictures…

…along with, I also collected some information from him over phone.

à One of the visiting birders (Jonathan from South Africa) also saw this species and several other Warblers. There was certainly Syke’s Warbler in the group along with this mystery Warbler which was different.

à In the earlier photographs, it is likely that he (David) muddled up the birds with Syke’s Warblers.

à Jonathan felt that this particular bird was Large-billed Reed Warbler

“I must say that to me these pics look much more convincing. They clearly show an acrop with a long bill, very short wings and large claws. These pics are very similar to the Kolkata ones last year.

As Large-billed has hardly ever been seen live in the wild could you ask David to provide much more detail on behaviour and calls. I assume he is no longer claiming it is nesting.”

Bill Harvey

“I find the bird very similar - however, I must mention that I have never seen the Large-billed with tail folded – every time we have seen it and every image obtained has the tail fanned out (sometimes a little - sometimes fully) - in fact when we saw it briefly this year that was the 1st thing we noticed - tail fanned out as it moved about. Does David have an image with an open/spread tail - that would perhaps, strike a stronger chord with my field views?”

Sumit K Sen

Tail-fanning behaviour of this Warbler

“Definitely more interesting and more convincingly an acro rather than a hippo having seen the most recent photos. (Clearly the earlier photos did not all show the same bird.) Overall I'd say that it doesn't look quite as large-billed as the photos of Phil and Sumit but nevertheless does not really have either a Blyth's or Clamorous Reed look to it. Bill colour matches the Thai bird and the face pattern looks similar with short supercilium and a white crescent below the eye. It's unfortunate that we don't have photos of the upperparts or the wing formula (for this bird or Sumit's) but the wing at least does look similarly short, making the tail look quite long.

The tail fanning behaviour seems extraordinary - I don't know whether this is regularly recorded for other similar species or not but if it is as distinctive for LBRW as suggested (e.g. Sumit saying "I have never seen the Large-billed with tail folded") then it is particularly odd that the bird hasn't been recorded much more often.

Not sure when the first sighting was but the first email I received was on 7 April so it (or others?!) has clearly been there nearly a month, which would be particularly odd for a spring migrant.

I'd be interested to see some input from any acro experts.”

Mike Prince

In another mail, David described the behaviour thus

“Its a high canopy feeder and rarely come down to feed. Anyway i will try to get more observations and photographs. Its behaviour like a leaf warbler. I saw the same species 30km away from my place and the same habitat & same tree (mango).They need good cover (canopy) to feed ,so i think if we search more in these area i will get more number. Anyway iam planning search similar habitat coming days. Iam making field notes which will help to know more about the birds’ habit.

David Raju

He also sent across another six photographs taken along with the previous three.

“Indeed these are looking much more encouraging. The very latest six shots from David show well fanned tails and long claws.”

Bill Harvey

Some more extra information I received from David by phone which I circulated.

“There seems to be three birds in and around the property of his resort. The other sighting which he mentioned (30km away) was the only other sighting. I quizzed on how he is sure the birds are the same species  - these are the features he had based his identifications on..

à Fanned tail most times
à Pointed tail feathers
à Larger bill with entirely pale lower mandbile
à Similar behaviour - sticking to upper/middle canopy.”

Philip D Round, who was away, finally replied to the mailing thread with the following information.

“Thank you for kindly keeping me copied on the correspondence and for sending me the pictures. Sorry not to have played a larger role. I am probably not the person to make any judgment

of these since I have not seen Large-billed Reed Warbler in the field- only in the hand! Also, I am often reluctant to make definitive judgments from photos, even of birds that are much easier to identify than Acrocephalus. However, I think these later pictures seem highly plausible for A. orinus. What else could they be?

It is encouraging that David is getting such good observations on them in the field and is collecting behavioural information. Is the habitat just too tricky to net them in, or is there nobody close at hand with mist-nets and handling skills? It would be ideal if one could be examined in the hand and a tail feather collected for DNA.

One wonders what the seasonal status of the birds is. After two caught in late March, plus the observations from early April in Kolkata last year, I was working on the assumption that LBRW is an early spring migrant, suggesting that it breeds in the N Tropics or subtropics rather than in the Palearctic. So, why haven't these birds left already? Kanha is quite a way south, yes? Is there any possibility they might breed locally around Kanha?

I look forward to hearing more of this story as it unfolds.”

Philip D. Round

Dear Praveen

Thank you for sending this document and photographs to me for comment.

Based upon what is visible in the photographs, the bird is clearly an
Acrocephalus; the long undertail-coverts and rounded tail shape rule out
Sykes's and all other Hippolais species. I must stress that I have no
experience of LBRW so my comments must be read in this context. However, I
agree with that when everything else is eliminated, the only option
remaining is Large-billed Reed Warbler.

The points made on tail-fanning behaviour and apparent preference for bamboo
are interesting, and these may give valuable clues to finding them in the
future.

I would agree with comments made that the early morning/evening behaviour
observed suggest a roosting bird rather than a breeding bird, and if
breeding, it would be likely that one or both adults would have been seen
bringing food to the bamboo clump now, since it is 6-7 weeks since the first
observations were made. Do you think it is possible that it could be a wet
season breeder, spending the drier months in central/southern India and east
to Thailand, then moving north and west with the monsoon to breed to the
north - the two Tring specimen come from Rampoor, Himachal Pradesh on 13
November 1867 and  Mussoorie, Uttar Pradesh, in October 1869.

What seems certain is that these recent records from India, plus two birds
from Thailand (including a returning adult there) suggests the LBRW is more
widespread than we could have imagined even 5 years ago. With observers
alerted to their appearance and behaviour, more records are likely and it
cannot be long until the breeding sites are discovered.

I wish you and your colleagues success in tracking down these elusive
warblers

Best wishes

Peter Kennerley

In conclusion, the current status of this Warbler indicates Large-billed Reed Warbler; however we might need more definite evidence before the same can be confirmed. Meanwhile, these pages will hopefully trigger other birders visiting Central India to look out for an odd Warbler.

Many thanks to Mike Prince for having started the email thread for identification and providing several comments on its identification. Special thanks to Bill Harvey and Philip D Round who kept the enthusiasm on and provided key insights into the identification of this bird – and for encouraging David to provide further field observations and photographs which lead to the current conclusion - despite having received photographs of the wrong bird in between. It was quite useful to have Sumit K Sen comment on the behaviour of the bird - he being the only person in the world to have seen one in the wild. Peter Kennerley was able to comment on the bird after seeing this page – many thanks to him.

Text by Praveen J

Pictures by David Raju