Himalayan Swiftlet: 2. An ornithologist’s perspective

posted in: Swifts-Swallows | 11

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The sighting of the purported Himalayan Swiftlet (Aerodramus brevirostris) together with a clear image of the bird shot from below by KC Tsang as evidence, has been reported earlier (left top).

I took the liberty of sending KC’s image to Dr David R Wells, author of “The Birds of the Thai-Malay Peninsular” and he kindly sent this reply:

“Good to hear from you, and thanks for the photo. The experts may indeed be sitting on the fence, but I do have to say that identification of the Peninsula’s grey (Aerodramus) swiftlets, from a still shot, particularly one taken from below, is hit and miss. THUS FAR, no-one has come up with a way of being certain. What I will admit is that the tail-fork is deeper, more conspicuous than I would have expected in a White-nest and certainly more so than in a Black-nest – leaving HS as the best bet.

“Seen in life, flocks of swiftlets with uniformly conspicuous tail-fork (such as shown) and rather stiff wing-beat I have tended to assume were HS, and passage movements of such birds have been noted over the S end of the Peninsula, including Singapore.

“Beautiful picture, nonetheless, and one of these days it could contribute to working out something more useful by way of ID characters.”

Black-nest (A. maximus) and White-nest (A. fuciphagus) are both common residents, the latter is also known as Edible-nest.

KC managed to get an image of the bird from above some time later (left bottom) and again I sent the image to Dr Wells. His response:

“Presumably not the same individual as before as tail-fork less pronounced (or it appears so; photos can be deceptive). All I will say is that any bird with a rump this pale relative to the rest of the upperparts, as far south as Singapore, could hardly be a White-nest. Given that Black-nests have the squarest tail of the three, the odds are in favour of Himalayan. BUT, this ID is still only statistical.”

In the absence of a live or dead specimen (or possibly more than one) in hand, the above images could be considered those of the Himalayan Swiftlet – all things considered.

YC Wee
Singapore
February 2008
(Images by KC Tsang and comments by Dr David R Wells)

References:
1. Robson, C. (2005). Birds of South-east Asia. London: New Holland.
2. Wang. L.K. & Hails, C. J. (2007) An annotated checklist of birds of Singapore. Raffles Bull. Zool. Suppl. 15:1-179.
3. Wells, D.R. (1999). The birds of the Thai-Malay Peninsular. Vol. I, Non-passerines. Academic Press, London.

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11 Responses

  1. Thanks YC for checking with David Wells. From his carefully worded reply, not one word mentioned it is a 100% sure ID bird. He mentioned “particularly one taken from below is hit and miss.. THUS FAR (yes in caps) no-one has come up with a way of being certain” BUT (again in caps) this ID is still only statistical”!

    This is contradictory to your first article on HM where your local expert mentioned it is easily ID in the field. Is he telling David Wells he is also living in an old fashioned mind-set too?

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  2. There is no contradiction. One is field ID, based on flight and other characteristics. The other is based on images.

    Yes, ID from an image cannot 100% at the moment. This is because KC’s images are the first for Singapore, nobody I am aware of, has attempted it before. Birders and photographers now need to work together to develop a useful way to ID the bird through images. This may mean getting images of other swiftlets for comparison.

    For the last so many decades, local birders have been ignoring swiftlets, preferring to observe less elusive species. That is, until KC started on his campaign of documenting these birds. Once he has images, birders are forced to decide on whether it is or is not an HS.

    KC has to be commended for stirring up the hornet’s nest, otherwise we will continue to ignore the question of whether HS exists in Singapore for the next few decades.

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  3. Agreed BUT your local expert should not have stated that this species is easily ID in the field. Out of the 7 who responded to KC Tsang image on BirdForum only 2 stated as HS. This is only 29%. That shows the difficulty in ID this bird even with a good image. For some strange reasons, your first article only extracted the response from Sean of Japan but not the rest of the respondents. And do you know that Sean later responded and thought it could be an edible-nest swiftlet instead of HS!

    The experts like David Wells has stated in his book “Given that field IDs are rarely linkable with a confirmation in the hand, there is still no certainty HS can be separated from other grey swiftlets in flight!

    I enjoyed reading your articles and you are doing a great job. I just hope that you are not biased in your reporting, that’s all.

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  4. To an experienced birder I am sure it is possible to ID HS in the field. How else do you think birders in Malaysia and Thailand ID this species but through the binoculars? To ID the bird from an image is a different kettle of fish altogether. For one, you cannot assess flight characteristics.

    You are incorrect in your assessment of the 7 who responded to KC’s image. Yes, 2 agreed it is HS. But the other 5 did not specifically say that it is not HS. They are not sure or do not know.

    Yes, Dr Wells agrees on the difficulty of image ID but he acknowledges, statistically, that the image, in all probability, can be that of HS. In the absence of a more established way of image ID, we can accept that.

    I try to be as impartial as I can in my postings. Should I be otherwise, anyone is free to point it out to me – as you are doing so now. In the search for knowledge, we should be as open as possible.

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  5. I do not agree with BESG response “that in the absence of a more established way of image ID, we can accept that”. Is identification of a bird species so important and pertinent that in the face of such uncertainty and non-commitment, even from one so renowned and acknowledged an ornithologist like Wells (and I am very sure many, many more in the birding fraternity), one needs to nailed it down as HS? Ben has rightly pointed out that Wells, in his book had stated that “there is still no certainty Himalayan can be separated from other grey swiftlets in free flight” and you had responded that “to an experienced birder I am sure it is possible to ID HS in the field” – is this then not contradictory? Or are we to discard Wells’ views above and accept your local expert’s assertion that it is indeed a HS? I do not know of your experience as a birder, but reading your postings have made me feel that you are also able to ID a HS in flight with certainty. Your assertion that “how else do you think birders in Malaysia and Thailand ID this species but through the binoculars” is also very haphazardly put forward and is selective. Historically in Malaysia, Medway & Wells (1976) had separated this species in the HAND from Black-nest Swiftlet on wing-length, tail furcation etc…while in Thailand, Deignan has had the opportunity too of many birds in the hand to be able to separate them even into the different sub-species (Swifts – A Guide to the Swifts & Treeswifts of the World 2nd Edition by P. Chantler & G. Driessens). It is probably through such in-the-hand analysis that HS is in both countries checklists, and NOT as you were trying to have readers believed – that they are identifiable just by looking “through the binoculars”. And if one wants to and insists that a flying swiftlet is a HS in both of these countries just by looking “through the binoculars”, it is their prerogative. In my opinion, it is always better and more prudent to err on the side of caution. It is also wiser. Adding another bird into a country’s checklist is not difficult, but care has to be doubly exercised to ensure that a new addition is beyond reproach and questioning.

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  6. I totally agree that we should be open as possible. As such i have extracted the response from Birdforum :
    Asian Palm Swift – 1
    Himalayan – 2
    Edible-nest – 2
    Not sure – 2
    The facts speaks for itself, 2 out of 7, It is still inconclusive. The point is you did not state that in your article but just focus on one single respondent who confirmed it as a HS. This give your readers a distorted view. You also did not state the fact that this single respondent later change his mind and thought it could be a Edible-nest Swiftlet. Is this impartial reporting ?

    David Wells in his book, “Birds of Thai-Malay Peninsula, 1999” stated clearly that there is no certainty HS can be separated from other grey swiftlets in free flight? Is anyone going to dispute this eminent ornithologist?

    I understand that even Chris Hails and LK Wang, two well-known ornithologist did not include the HS in their latest Singapore bird checklist but put it under appendix. If it is so easily ID in the field, as what you stated, i’m sure they would have put it in. Why then not ? Some food for thought…

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  7. KC’s image of the HS is really stirring birders out of their complacency. Well and good!

    It is Sue’s prerogative not to agree with our conclusion. However, she has raised a number of relevant points that need to be answered. These will be dealt with in a further part to the series – the comment section cannot do justice to the discussion.

    However, it is necessary to get Ben’s “2 out of 7” “statistical analysis” out of the way first.

    There was a request for help to ID HD in Bird Forum. Seven responded, making helpful comments and casual remarks about possible IDs. Only one gave a serious reply. It is too simplistic to just count the different species thrown up and conclude that it is 2 for HS and 5 against. I hope Ben is not serious in wanting me to bring all these up in my earlier discussion.

    Anyway, keep a lookout for Himalayan Swiftlet, Part 3.

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  8. I was just trying to response to your previous reply when you said 02 agreed it as HS but the other 05 did not specifically say that it is not HS, which is not true. The other 05 did response with various answers. That’s why i broke it down. If u would have stated there were various responses and answers from BirdForum (in your 1st article), one of which from Sean of Japan, then it will make a fair and impartial article for all your readers.

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  9. You have your style of writing and “statistical analysis”, I have mine. Long live the difference!

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  10. This HS controversy has being going on for the longest time. Science believes in facts & proof.

    Why don you guys devise a trapping method & trap 1/2 suspected HS & do specific tests? Instead of arguing about it on paper till the cows come home?

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  11. Yes, go catch it!

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