First WP Asian House Martin?

Barak Granit 27/12/2016 00:00

 

On December 16th, after relocating (Tomer Landsberger and I) the 4th Israeli Slavonian Grebe, that was found the day before at Ma'ayan Zvi fish ponds along the northern Israeli Mediterranean coast, I spotted a Red-rumped Swallow which is extremely rare in winter. We stopped to have a good look at it, just in case, and while I tried to photograph it I spotted a strange looking House Martin.  Owing to certain features that I knew from published literature and noted on spot, I suspected it to be an Asian House Martin Delichon dasypus, a species not yet recorded in Israel and through the WP.

 

 

 

 

I took as many photographs as I could, we both had prolonged views enabling us to note as many features as possible and check more features through the net at the time the bird was still around. During the next days the Martin was heavily twitched by many Israeli birders and some more photographs were taken in better light conditions (it was heavily overcast and sometimes rainy on the 16th). Five days later, on the 21st, I returned to MZ alone, and was amazed to find the bird perching on fishponds cables with many Swallows, enabling me to take much better photos. Although looking good, and although there is a growing positive consensus in Europe and Israel that this bird is likely an Asian House Martin, I will take a cautious position and still regard the bird as potential/possible AHM.

 

 

Asian House Martin (Delichon dasypus) is a similar species to European House Martin Delichon urbicum, that breeds in Asia far away from the WP. Three subspecies have been described:

(1) dasypus (nominate) breeds in easternmost Russia, Japan, Korea and east china, all along the pacific. It is considered to be a long distance migrant that winters in Indonesia, Malesia and south-east Asia. Due to its long movements, it is considered to be a potential vagrant to the WP.

 

(2) cashmeriensis breed all along the Himalaya and trans Himalaya range from northern Burma and south-central China and eastern Tibet in the east through northern India, Nepal to northern Pakistan and easternmost Afghanistan at the west with an isolated population in northern China. It is considered to be a short distance migrant, roaming to lower altitude in winter, but wintering grounds in Central-eastern India reveal that at least some birds move further away.

 

And (3) nigrimentalis inhabits the south eastern part of the species range which to date has not been well studied (Turner and Rose 2010).

 

Identification:

Here I will emphasize the key features of this bird and will shortly discuss their importance.

The bird identified as 1st-winter currently starting its complete winter moult on P1 (asymmetrical, left wing only). Head and body moult hasn't started yet. The bird also has grown tail feather 5 in one side only indicating a feather loss as a result of (probable) accident.

 

1. The dark underwing coverts. It is commonly regarded as the most important feature together with the black chin feathering and the shallow tail-fork (see below). The MZ bird shows clear dark, blackish underwing coverts. It appears so in different light conditions, both sunny and overcast weather and in all photos. Some internet images show dark underwing coverts of the 'doggy' juvenile urbicum but these are probably a result of light condition rather than reflecting the real covert color.

 

 

 

 

2. The tail-fork: this bird shows quite a shallow tail fork compared to that of juvenile urbicum. It appears so when the tail is both relatively close or open in comparison to parallel tail postures in urbicum. Furthermore, the whole tail projection behind the trailing edge of wing seems relatively short in comparison to urbicum, resulting in more compact Jizz as appears in dasypus.

 

3. Rump and uppertail coverts - another supportive feature is the mottled white rump. However, some juvenile urbicum may also show a different degree of mottling on the rump thus this feature can be considered as supportive only .

 

4. The upper-tail coverts are black or blackish in centers with juvenile white edges. The black feather centers of the upper-tail coverts exclude East Asian House Martin Delichon urbicum lagopodum which in comparison to nominate D. u. urbicum has darker underwing coverts and shallower tail-fork, but has white upper-tail coverts forming an extensive white rump, opposite to the MZ bird that has a rather limited white rump area.

 

5. Under-tail coverts - the bird has large dark centers to the feathers of the under-tail coverts. It is again supportive feature of dasypus but since some juvenile urbicum show some dark centers it is important to compare the exact pattern if there is any difference.

 

6. Throat and Underparts: the bird shows a pale whitish-grayish throat: whitest at the throat-sides just beneath the dark ear-coverts contrasting (stronger effect in poor light) to the grayer throat-center, which is speckled with darker spots right beneath the chin. All in all the entire throat contrasting to the darker grey pectoral breast band and the gray wash to all underbody.The flanks are darker gray than the belly all along. Some of the doggy European House Martin, including the 'dusky' House Martin from Flamborough 30 October 2013 http://birdingfrontiers.com/2015/08/07/dusky-house-martins/ seems to have an opposite pattern: white body and darker throat. Regardless to the identity of the Flamborogh bird (which has clearly paler coverts and deeper tail-fork than the MZ bird), that pattern is found often in juvenile European House Martins.

 

7. The Chin - critics pointed out that the MZ bird lacks the black chin feathering appearing in most photos of Asian House Martin as reflected on many internet images. Indeed, a black chin feathering would make a case closed, but the MZ is juvenile and apparently there is very little material on juvenile AHM chins or photos of juvenile AHM at all.

 

Yet, the MZ bird shows a clear dark line dropping from each side of the bill base, well below it. The real chin center just below the bill appears whitish, but it is surrounded by grey feathers creating a half moon-shape facing up. And the whole area having dark speckles in it. This pattern appears at least in two photos: scroll down here ( http://islamabadbirding.blogspot.co.il/2013/06/new-birds-in-ayubia-national-park.html ) - the two juveniles in the nest of ssp D.d. cashmeriensis taken in northern Pakistan in a colony of 20 Asian House Martin. Both birds show very similar chin pattern to the MZ bird with dark lines dropping down from bill base and pale chin surounded by grey feathers.

 

Scroll down here https://digdeep1962.wordpress.com/2013/12/18/langkawi-kedah-13-15-december-2013/   and check the middle AHM among the 3 AHM photos for another pale chin bird taken in December 2013 in the winter grounds in Malaysia.

 

Another pale chin skin of a bird that is said to be juvenile was collected in Java Indonesia as well https://commons.wikimedia.org/wiki/File:Naturalis_Biodiversity_Center_-_RMNH.AVES.46891_2_-_Delichon_dasypus_dasypus_(Bonaparte,_1851)_-_Hirundinidae_-_bird_skin_specimen.jpeg.  It seems that at least some of the juvenile of AHM show a pale chin thus the pale chin of the MZ bird cannot be taken as a contradicting feature while the dark lines dropping from both sides of the bill base may appear as indicative feature while further work is needed to establish this.

 

Apparently pale chin is not appearing on mere Juveniles. Check out these two adults taken at the nest at Bhutan of ssp D. d. cashmeriensis ( http://www.hbw.com/ibc/photo/asian-house-martin-delichon-dasypus/adults-nesting-colony ). The bird at the bottom has hardly or lacking completely a pale chin (and actually has dark lines dropping at each side of bill base as in MZ bird) while the upper bird clearly has one. It is really interesting to learn how vary is this feature among adults or between subspecies, too. Apparently at least some may not show it at al.

 

8. Other features: the bird has a partial white surrounding to the ear-coverts, something that appears on AHM but usually lacking in European House Martin. I wouldn't sign on this feature but it seems like another possible supportive one.

 

9. Moult - timing of moult should be taken as supportive feature only as some birds don't 'obey' their species moult timing program. In other words - it should be taken with care. Once said that, European House Martins leave the nesting sites in august/September and the bulk of passage in Israel occurs during September.

 

 

The birds reach their wintering grounds during October to start their complete winter moult that occurs between Oct (Nov)-February (Ginn and Melville 1983). Asian House Martin said to leave their breeding grounds a month later in October (Turner and Rose 2010, del Hoyo et al. 2014). Sample photo check of AHM from December reveal they had not start their winter moult. The MZ bird only growing now (has not finished) its first primary and in one wing only, means it has started its winter moult on the first week of December for the earliest, something that at least in theory fits better Asian House Martin.

 

 

 

In summary, it seems we are having the best documented candidate of Asian House Martin in the Western Palearctic up to date. We still have to verify the appearance of the pale chin on juvenile birds, but it seems by available photos that at least some juveniles appear to have a pale chin, while the dark lines in dropping at each side of the bill base require a skin work in museums being perhaps an indicative or even a diagnostic feature of Asian House Martin (future will tell). From a different point of view, it seems quite unlikely (at least right now) that a European House Martin, as doggy as it can be, will show such a combination of Asian House Martin characteristics, on both plumage and morphology.

 

 

 

 

 

I'd like to thanks Yosef Kiat and Eyal shochat for reviewing this article

Barak Granit

 

del Hoyo, J., Elliott, A., Sargatal, J., Christie, D. A., & de Juana, E. (2014). Handbook of the birds of the world alive. Lynx Edicions, Barcelona.‏

Ginn, H. B., & Melville, D. S. (1983). Moult in birds. BTO Guide 19. British Trust for Ornithology, Tring.‏

Turner, A., & Rose, C. (2010). A handbook to the swallows and martins of the world. A&C Black.‏

 

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