Monday, 10 February 2014

Obscure bird of the week: Large-billed Reed Warbler

A few of us, here at Next Generation Birders, came up with a great idea. The world's press drools at the thought of conserving species that are 'sexy'. Species like spoon-billed sandpiper (Eurynorhynchus pygmeus), polar bear (Ursus maritimus) and giant panda (Ailuropoda melanoleuca). Our idea was to spread the word of some of those bird species that may not be quite as well known as the headline species; species that you almost certainly have never heard of; species that could do with 15 minutes of fame to help with their public profile and make people care about them a little more.

Therefore, without further ado, let me introduce you to the ultimate "Obscure bird of the week": This not only is a bird species that you will probably never have heard of, but is a species that scientists have labelled 'The Least Known Bird in the World'!
Check out that Dowitcher-like bill! ©Pavel Kvartalnov
The large-billed reed warbler (Acrocephalus orinus) - a very rare species that looks very similar to other species of Acrocephalus warblers, so is very subtle and hard to detect.

Not only is it not in the public domain, but even within science, it is someone of a question mark. Originally discovered 1867, it was seen three times in total. The warbler managed to remain hidden for the entirety of the 20th century. The species had only ever been seen in its presumed breeding grounds of Afghanistan. As a result, ornithologists elsewhere across Asia certainly didn't have the species in their radar.
Wing formula - the epitome of birding coolness!
It came as a great surprise then in 2006, when a large-billed reed warbler (LBRW) was caught and ringed at Laem Phak Bia in Thailand. Subsequently, their migratory range has received a better estimate and a previously labelled Blyth's reed warbler (A. dumetorum) museum specimen from India in 1869 was reidentified. In addition to this, 'Blyth's' museum specimens from central Asia, Myanmar and India have been re-identified to large-billed. 

The large-billed reed warbler has been likened to Blyth's reed warbler due to it's short-winged appearance compared to the other Acrocephalus warblers. There different in wing fomula is subtle, but 'fatter' tips to the primaries with less emarginations are evident. Now I know what you're thinking...they're not likely to catch one on Fair Isle, so why are you telling us the wing formula?
Well as with most warblers, without hearing a singing bird, it's ruddy difficult to split species. The only current behavioural trait that seems to be different in LBRW is that, when foraging, they seem to fan their tail. 

The population is still very much unknown though, so there is not enough data to assess the population size, population status (it is thought to be very rare, but the stable, or slightly in decline). They are assumed to breed in Afghanistan and then winter in India and eastern Asia. 
LBRW: The movie
Coming to cinemas in Tajikistan 2039
During 2008 and 2009, there were a small handful of possible breeding populations located in Afghanistan, so there is hope for further analysis of their population estimate. The story is far from over....

-Zac Hinchcliffe
When Zac's not counting birds on patch, he's usually ringing birds on his regular Bangor site or is depressed that he does't have the money or time to twitch the latest big thing. Zac is 21 and currently studying a Research Masters at Bangor University and investigating Welsh Twite; adding a touch of science to his birding.

1 comment:

  1. We checked the Blyth's Reeds in Uzbekistan in May 2010 for these bad boys, no such luck *but* perhaps they don't occur any further north than Afghanistan anyway. Worth a try, though!