Wednesday, June 26, 2013

Cambodian Tailorbird: a new species for the world!

Inception. 5:30 AM on 23 June 2012. The moment when my suspicions that the odd tailorbirds on the outskirts of Phnom Penh might represent an undescibed species were confirmed.

If you’re reading this then you probably already know the end of this story: a year ago a new species of tailorbird was discovered just outside Phnom Penh. The type description was released today, you might have already read it or seen the press release or read the news reports. However there isn’t enough space in a scientific paper or a news story to give the full account of what happened, so that’s what I’ll do here.
The first beginning. One of four Cambodian Tailorbirds caught and released in 2009.

Way back in 2009 I was working for BirdLife in Vietnam, and doing plenty of exciting birding. Unbeknownst to me at the time four Cambodian Tailorbirds were mist-netted near to Phnom Penh, and released. The birds provoked discussion among those present and it was decided that they were Ashy Tailorbirds, at the time the only records of that species for Cambodia. With the benefit of hindsight it is possible to see that the bird above is not an Ashy Tailorbird, but very few photos were taken, and those that were taken were poor and (with the exception of the above) suffered from colour bleeding.

Preh Ksach: lovely.

I moved to Cambodia with my wife Sarah in January 2012 to start a new job with WCS Cambodia. The first birding that I did was at Preh Ksach, a partially flooded construction site on the outskirts of Phnom Penh, 30 minutes drive on a good day. It was a Sunday afternoon in mid-January and we were doing the AWC count. We saw a good number of waders, the highlight was two Red-necked Stints, a good inland record. Two weeks previously Howie Neilsen had found another of those Ashy Tailorbirds at Preh Ksach. I had previously kept a very respectable Vietnam list, which had included Ashy Tailorbird in the mangroves near Saigon. I didn’t have any aspirations of competitive Cambodia listing, Howie was pushing 500 (over 80% of the Cambodian list!) and I didn’t see much point in competing. So I made little effort to look for his tailorbird, and guessed that since I would be using Preh Ksach as something approaching a local patch I was bound to bump into it eventually.

The second beginning. 9 June 2012, Preh Ksach, Ashish John.

A busy first dry season in Cambodia meant that little birding was done during spring. On 9 June 2012 my colleague and friend Ashish John took advantage of some free time and cycled to Preh Ksach for some bird photography. Ashish was very pleased to have photographed the Ashy Tailorbird, in the same place that Howie had seen it five months previously. He uploaded the photograph above to this blog and I immediately commented “Interestingly, there is more rufous on the crown than the Robson guide illustrates, Craig shows it going only as far as the eye, but on your bird the whole crown is rufous”. Ashish uploaded more photographs of the bird, reproduced here: 

This got me wondering. The plumage was clearly worn but these non-Ashy features were not a photographic artifact: why was it so dark on the breast? On 12 June I sent an email to various relevant people alerting them to the photographs on the blog and attaching some photographs of the 2009 birds (which at the time I thought were one bird). The answers I got back swung between Ashy with some non-standard features to odd Dark-necked. There was a general consensus that more work needed to be done. Some people started to sound excited. On Monday 18 June a hasty pre-work visit to Preh Ksach was arranged with Tom Evans and Ashish. We located the bird and Ashish got some more photographs of it and another similar individual:

The biggest revelation on that morning was that it didn’t sound anything like Ashy Tailorbird, it sounded like Dark-necked Tailorbird! Something was definitely up, but all of this took a while to sink in. On Monday I was still convincing myself that these were aberrant Dark-necked Tailorbirds. On Tuesday I emailed more people, this time listing the features by which these birds differed from Ashy and Dark-necked Tailorbirds. Broken down like this it was clear that other than the greyness they were more like Dark-necked Tailorbird than Ashy; Ashy was now completely out of the equation. By Wednesday I was writing that I thought they were neither species. Will Duckworth sent encouraging noises and drew comparison with the Bare-faced Bulbul discovery: it began with years of various people looking at the birds but not seeing what they really were, and wasn’t solved until Ian Woxvold stood so close to one bird that he could see the colour of the inside of its cloaca and the minds of those involved finally opened up and allowed their brains to see what the eyes had been looking at all along.

On Friday I noticed that the 2009 photographs showed at least two individuals. We now had at least four aberrant Dark-necked Tailorbirds or……! I didn’t want to say it. This wasn’t a bird on some remote mountain somewhere, or an unexplored island, it was in some dirty scrub, on the edge of Phnom Penh! Almost every Asian birder worth his salt had been here already (Craig Robson would probably like me to point out that he didn’t visit Cambodia until 2013) and driven past swathes of this awful habitat. Surely it couldn’t be what I thought it might be? Not here, in front of me!? But it was either ‘that’ or an aberrant Dark-necked, which was looking like an increasingly unlikely option. My thoughts on how to eliminate the aberrant hypothesis were Bulo Burti Bou Bou boob shaped: in the case of this taxonomic boo-boo it was impossible for those describing the species to find more than one individual fitting a novel plumage type, and what they described as a new species was eventually shown to be an aberrant individual, or more generously a morph, of one of those other African birds. So the proof, I thought, would be if we could find a population: you don’t get a localised population of aberrant birds that all look the same, that’s a subspecies, or if it looks different enough then you call it a species, and these things certainly looked different.... So with this in mind, I gathered Howie and Ashish early on 23 June 2012 (Sarah’s birthday, although she was away with work) to join me to test this theory.


And so on....!

Please excuse the horribly over-exposed photo of Howie and Ashish above, my brain was by this stage evidently non-functionando. The first bird flew in whilst it was still almost dark (see the very first photo on this post), I got my bins on it as it bombed across the marsh in response to the tape: a little grey blob with a rufous cap and white cheeks. It landed on the Mimosa in front of us and I knew then what we had done. We played the tape at every patch of scrub we found, and produced bird after bird after bird, all of them individuals of this new thing. We were wearing flip-flops! Excitingly, we saw both males and females; and the females looked exactly like you would expect a female version of a tailorbird that looked like the males to look. We also dropped in on a spot half-way between Phnom Penh and Preh Ksach, a mere 6 km straight line distance from our office, which Ashish had cycled past on 9 June and apparently heard one of these birds. Sure enough, they were there as well. We were back in Phnom Penh in time for lunch, so I wrote an email to those who had been involved in the initial email discussion, who gave it their blessing. I felt a bit strange for the rest of the day.

Summer in Cambodia is typically dire for birding, so it was good to have a distraction. Ashish and I, often joined by Colin Poole and sometimes joined by Hong Chamnan, embarked on a summer of ‘tailorbirding’, as it became known. This consisted of picking bits of suitable habitat on google earth, driving to them, winding down the car window, playing some tape, taking some photographs of the tailorbirds, taking a GPS point, and driving on somewhere else. In hindsight we should have brought more picnic items on these trips, but it was typically so hot by mid-morning that we were pleased to be back in Phnom Penh for lunchtime. All of this was done in a state of sheer incredulity: we had found a new bird species, in Phnom Penh!!!



One of the key questions we wanted to answer was ‘how does its range interact with that of Dark-necked Tailorbird?’, a species which also occurs in floodplain scrub, particularly at the north-western end of the Tonle Sap Lake where it is abundant. We still haven’t totally answered this question. We also wanted to look for hybrids, so we were shocked to see this abomination on 16 July 2012.

Aaaaaaarrgh! Was it a hybrid, had this whole thing come crumbling down in front of our faces? Or was it yet another new species? Two for the price of one! It felt like anything was possible. A couple of nervous weeks followed and then we saw this:

Phew! It’s moulting out those green-fringed feathers, that was the juvenile plumage! There were quite a lot of birds like this as well. The adults were also moulting into nice fresh plumage.

There’s not much else to add. I got on with the type description with the help of Ashish, Hong Chamnan and Colin at WCS, Jonathan Eames at BirdLife International, Fred Sheldon at LSU, Carl Oliveros and Rob Moyle at KU and Howie at the Sam Veasna Centre. I enjoyed visits to the collections at Leiden (with James Eaton who had just discovered that the parrotfinches that you’d all been seeing for years on the top of Gunung Mutis on Timor were an undescribed species!) and Tring (with my Mum). Nigel Collar, Brian Sykes, Stu Butchart and Richard Thomas at the OBC (you should join if you haven’t already: do it for the birds!) were immensely supportive, whilst a whole load of other people also played a part (I’m in danger of repeating the acknowledgements section of the paper here, so I’ll stop). Quite a number of people have enjoyed the bird in the field since we elucidated its true identity and many of them offered me much appreciated encouragement. Frank Rheindt and Martin Kennewell were particularly good company on the first ever 'Cambodian Endemics Clean-up Weekend'. If you’re also keen to see the tailorbird (it is the walk-in-the-park type bit of a weekend devoted to Cambodia's endemics) them I’m more than happy to give directions, just drop me a line. Even if you don't see the birds, spending a day in habitat like this is an uplifting experience.

For me this last year was an incredibly exciting learning experience. The first thing that I learned was that it’s better to be lucky than good. This was reinforced when a Rufous-headed Robin spent five days in my garden in November. It’s worth noting that since 1963, the year of the only other record of Rufous-headed Robin from outside of the breeding grounds, seven new bird species were described from Southeast Asia. I hope that this experience has taught me to question everything, to look at everything as if for the first time, evaluate it and not lapse into probability based identification. I now believe more strongly than ever that you almost always see only what you expect to see. Inattentional Blindness is rife in birding. When I could not conceive that the Cambodian Tailorbirds were a new species they looked rather like Ashy Tailorbirds, then gradually they looked like Dark-necked Tailorbirds, then..... Looking back at the photographs from 9 June 2012 it is so obvious that they are neither Ashy nor Dark-necked Tailorbirds, but initially I just couldn’t see what those birds really were. Looking at the pictures on this blog from your armchair you you're probably shouting at the computer right now, acting just like people who shout at the TV in incredulity when watching one of those documentaries about everything going wrong for inadequately equipped people on a mountain. Without wishing to unravel a whole new world of string, I think that you should expect to see rare birds, unexpected birds and even birds which haven’t even been conceived of yet. Unless you expect them, you will look at them but not see them, even if they drop into your garden….

Simon Mahood, 26 June 2013

Friday, June 21, 2013

White-winged Black Terns on the Tonle Sap

From 04--6 June 2013 I was at Prek Toal for work. Tern numbers were much reduced from their winter high, but the species composition was much more interesting. During winter 1000's of Whiskered Terns can be found in the open water near to Prek Toal. I saw only 100 or so terns this time, but only about half of them were Whiskered...most of the rest were White-winged Black Terns!

White-winged Black Tern is thought to be barely annual on the Tonle Sap, but it seems that non-breeding birds might over-summer in some quantities, at least they are doing so in 2013. Most of the birds were in first-summer plumage, but about 20% were adults. The adults were in a complete mixture of plumages, from full summer to full winter with everything in-between.

For added value there were also two adult tibetana Common Terns and one adult Caspian Tern. 

Here's a couple of adult White-winged Black Terns

 Simon Mahood