Asian House Martin – Coming Soon To A Headland Near You?

Asian House Martin (Delichon dasypus) must be a candidate for vagrancy to Western Europe.  At least one of the three subspecies is a strong and long distance migrant. However, looking very similar to its common European sister-species, how many people would be able to identify one?

The nominate Asian House Martin is perhaps the most likely to wander.  It breeds in southeast Russia, the Kuril Islands, Japan and Korea and migrates through eastern China to winter in the Malay Peninsula, Borneo, the Philippines, Java and Sumatra.

Ssp cashmeriensis breeds in the Himalayas from Afghanistan east to Sikkim and northwards into Tibet and western and central China. It is a short-range migrant, mainly wintering at lower altitudes in the foothills of the Himalayas.

The third race, ssp nigrimentalis, breeds in southeastern China. Its wintering grounds are unknown, but birds in Taiwan apparently just move to lower altitudes in winter.

In eastern China any sighting of a House Martin is notable.  I have seen a handful of both Asian and Northern House Martins at Laotieshan in Liaoning Province but, in a sign of just how scarce they are in this region, I have still not seen one of either species in Beijing (they are passage migrants and seen in small numbers each spring and autumn – clearly I just haven’t been trying hard enough!).

A recent visit to Chang Bai Shan in Jilin Province, northeast China, provided an opportunity to get to grips with Asian House Martin as several pairs were nest-building on our hotel, allowing some fantastic views.  Capturing any hirundine in flight with a camera is not easy, and the images below won’t win any prizes, but they do show some of the features to look out for in separating Asian House Martin from Northern House Martin.  It’ll be worth making a mental note of these features when checking out those late autumn migrants….!

Asian House Martin (Delichon dasypus), 27 September 2011, Laotieshan, Liaoning Province, China. A typical flight view from a migration hotspot in excellent light. Even with a relatively distant view, the dusky underparts – sometimes even a greyish-washed breastband as shown on this bird – contrasting with the white throat and the dark underwing coverts are all visible.

Asian House Martin, Chang Bai Shan, June 2012. This image was taken at much closer range and in heavily overcast conditions. Again, note the dusky underparts contrasting with the white throat, the dark underwing coverts and the squarish tail.

There are several features that, with decent views, should enable identification of a vagrant Asian House Martin.  Structurally, Asian House Martin is smaller, more compact, shorter- and squarer-tailed than Northern but these characteristics aren’t necessarily easy to ascertain on a single bird.

On plumage, one feature that I have found helpful in the field, is the colour of the underwing coverts.  In the images above, taken in both sunny and dull conditions respectively, one can see the relatively dark underwing coverts, a consistent feature of Asian House Martin.  Compare with this image of a Northern House Martin.  The paler underwing coverts of Northern are not usually as prominent as shown in this linked image (taken in strong light) and can often appear concolourous with the rest of the underwing but a House Martin with obviously dark underwing coverts should be Asian.  Note also the deeply forked tail on Northern House Martin relative to the more shallow, ‘squarer’ tail of Asian.

Asian House Martin, Chang Bai Shan, June 2012. Note the dark speckling in the rump, another good feature of Asian House Martin.

Another feature is the rump.  On Asian House Martin the white rump is usually relatively small and can appear ‘flecked’ with dark streaks, as in the above image.  On Northern the white rump is larger (due to more of the uppertail coverts being white) and is usually clean white.

Asian House Martin, Chang Bai Shan, Jilin Province, China, June 2012.

Asian House Martin, Chang Bai Shan, Jilin Province, China.  This image shows the dark feathering under the lower mandible.  On Northern House Martin, the chin is white.

Another subtle feature to distinguish these two species is the amount of black on the face.  Compare the two images above of Asian with the image of Northern.   The black on the face generally extends a little lower on Asian, producing a dark ‘chin’.  Tough to see in the field but, with good photos, this should be discernible.

Finally, check out these excellent images from John Holmes in Hong Kong showing the full range of features.   The contrast between the dusky underparts and the bright white throat is often the most obvious feature of Asian House Martin in the field.

So, in summary, the combination of a smallish white rump (sometimes flecked), dark underwing coverts, ‘dirty’ underparts contrasting with a clean white throat, a shorter, squarer tail and a darker ‘face’ are all characteristics associated with Asian House Martin.   Maybe one will turn up at your migration watchpoint this autumn…?

 

10 thoughts on “Asian House Martin – Coming Soon To A Headland Near You?

  1. Jochen Dierschke

    Nice subject! I think there was one seen in Falsterbo/Sweden by a very experienced Birder a few years ago – don’t know if it was accepted though.
    I would not stress the darker breast too much – juvenile Northern can show this as well. We had one even this spring, which showed also a smaller wehite rump and was by several birders as a hybrid Barn Swallow x House Martin. In fact I should check the pictures soon …

    Reply
    1. Terry Townshend

      Thanks Jochen. You are right to exercise caution about one specific feature. It is always prudent to make an identification based on a suite of features rather than rely on only one. I do recall the Swedish claim (by Nils Kjellen, I think?). It would be interesting to know whether that record was accepted. I will try to find out.

      Reply
  2. linosabirding

    …And also the underwing coverts are often rather dark in juvenile House Martin, contrary to what illustrated in most field guides. I could upload some photos in the hand of those
    ciao
    Andrea

    Reply
      1. Terry Townshend

        Thank you, Andrea. It would be nice to see some photos of juvenile Northern with darkish underwing coverts. Maybe the dusky underparts contrasting with a pale throat is a key feature to look for.

  3. Hans Larsson

    Here is a link to photos of the swedish bird:

    http://www.artportalen.se/birds/gallery_imageinfo.asp?imageID=94435

    Along with the description from the observers (the bird was initially at a low altitude at very close range (10-20m)) it seems a really good contender.. They primarily noted blackish underwings, clearly smaller size and a blunter wing and shorter tail than the numerous EHM present. However it was rejected due to the poor documentation.

    Reply
  4. Laurent Vallotton

    Here some images of D. urbicum from Switzerland with relatively dark underwings (links taken from ornitho.ch:
    http://media.biolovision.net/www.ornitho.ch/2011-06/2808-4484630-2615.jpg
    http://media.biolovision.net/www.ornitho.ch/2012-09/1525-5579557-1006.jpg
    http://media.biolovision.net/www.ornitho.ch/2012-07/6636-5461728-8857.jpg
    http://media.biolovision.net/www.ornitho.ch/2012-06/1525-5399166-5449.jpg
    http://www.ornitho.ch/index.php?m_id=54&backlink=skip&mid=153180

    Reply
  5. Pingback: Dusky House Martins | Birding Frontiers

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