Riparia martins in Malaysia: What are they? (Part 1)

The highlight of our Malim Nawar visit on 2 Feb for me was not my first ever Malaysian Tufted Duck, but the discovery of a large number (40+) of Riparia Martins, many of which were perched at eye level at close range.

Ever since Dec 2006, when I started observing these birds in Penang, I’ve had a bit of obsession over them, and this was the opportunity I had been waiting for to study them at close range. In fact, the opportunity was so good, I decided to make a second trip on 11 Feb so I could spend the whole day watching these birds.

Before I get into the detail of what I saw, I thought it would be useful to pull together all the information I’ve been able to glean from various sources about the Riparia martins that are or might be occurring in Malaysia, Since people have been asking, I’m taking the unusual step of putting this in my blog rather than publishing it elsewhere, in the hope that a) it will be freely available to as many as are interested b) others can add to what is written here.

Background

There is only one species of Riparia martin on the Malaysian list – R. riparia – Sand Martin (MNS, 2005) (also known as Common or Collared Sand-Martin). Wells (2007) describes it as a non-breeding visitor present from August to April, with numbers varying from year to year.

However, there is a distinct possibility that another very similar taxon, Pale Martin R. diluta may also winter in Malaysia. Pale Martin was only recognised as distinct from Sand Martin in 1993 (Goroshko, 1993), so it is hardly surprising that this species is one of the least known hirundines in our region.

Known Distribution of Sand and Pale Martin in East and South-east Asia

The breeding range of Pale Martin extends from Central Asia east to Central and Eastern China, while the wintering range is still poorly known. Of the six subspecies currently recognized, two could occur within south-east Asia; R.d. tibetana, which breeds in western China, and R.d. fohkienensis (sometimes spelled fokiensis), which occurs in summer in central and eastern China and winters in southern China. Additionally, Robson (2008) records it as wintering in E Myanmar and E Tonkin, and occurring as a vagrant in Peninsular Malaysia (the source for this is probably my own records, none of which have been formally submitted for assessment).

There are five or six commonly recognized races of Sand Martin. R.r. ijimae is the only one known to occur in Malaysia. It breeds in northeastern Asia, including the Kamchatka peninsula and the Kurile Islands, south to the Amur River and Hokkaido (Cramp, Simmons and Perrins, 1995), and in Gansu province, north central China (P J Leader pers. comm.), and is recorded as an uncommon winter visitor in South-east Asia from northern Thailand south to Singapore (Robson, 2002). A helpful summary of races and their distributions is available here: (follow the links on the right), and a map showing the breeding distribution of both species is here: (pale grey = R.riparia; dark grey = R.diluta; striped area = where both species occur).

Recent changes in status in the region

In recent years, based partly on measurements of birds in the hand, Pale Martin R.d.fohkienensis has been recognized to be the commonest Riparia martin occurring in Hong Kong, and indeed, there are currently no accepted records for Sand Martin in the territory (G J Carey, pers. comm.). Sand Martins have been trapped and identified in the hand from measurements in Singapore (P R Kennerley pers. comm.), but most records in the region refer to field observations, and the possibility of fohkienensis Pale Martin may not have been eliminated.

Plumage, Structure and Vocalization

Field identification criteria which distinguish the fohkienensis subspecies of Pale from Sand Martin are scarce. Most work on field separation of Pale Martin from Sand Martin (e.g. Goroshko 1993, Loskot 2006, Schweizer and Ayé 2007) has been done on western races, and focuses on plumage characters such as overall upperpart colour, weakness of breast band colour and distinctness of head pattern, which generally do not apply in the case of fohkienensis.

Robson (2008) notes that fohkienensis Pale Martin can be distinguished with difficulty from Sand by the following characteristics:

  • slightly smaller and smaller-billed
  • slightly shallower tail fork
  • upperparts paler and greyer
  • underparts less clean white
  • creamy wash on belly and undertail-coverts
  • breast-band paler but neater, often faint in centre
  • dark smudging in centre of breast/upper belly indistinct or lacking 
  • pale tertials and inner secondaries can contrast strongly with rest of the wing.

However, recent observations of birds in the hand suggest that plumage characteristics are quite variable, and none may be diagnostic. “Fohkienensis are more variable in plumage terms than has been previously recognized, and I think the most important identification feature is size and structure” (P J Leader, pers. comm.).   

The main structural characteristics which appear to consistently differentiate adult Pale from Sand Martin (P J Leader, pers. comm.) are:

  • At rest, the wing tips of Pale Martin fall level with or beyond the tail tip, whereas on Sand Martin, the wingtips fall short of the tail tip.
  • The tail of Pale Martin is less forked than that of Sand Martin, appearing square when slightly spread, whereas a fork is still visible on a similarly spread tail of a Sand Martin.

Vocally, Pale Martin is said to be distinct in both calls and song from Sand Martin (P J Leader, pers. comm.). Unfortunately, there are no recordings of Pale Martin or ijimae Sand Martin on the web to faciltate direct comparison.

Measurements

In the hand, Pale Martin averages smaller than Sand, with shorter wing, tail and tail fork. However, this is complicated by significant differences in factors such as weight, wing length and tail length between adults and first winter birds of both taxa, with juveniles/first winters being lighter, and having, on average, shorter tails, and, usually, shorter wings and tail fork (Loskot 2006).

Tail fork

Sand Martin = usually >7mm

Pale Martin = usually < 7mm

There is some overlap, but birds with a tail fork > 8mm can be considered “most likely” to be Sand and not Pale Martin (Loskot 2006).

Wing Length

Though Pale Martins are usually smaller than Sand Martins, the zone of overlap in wing measurements is large. Loskot (2006) notes that birds with a wing measurement of >105mm  are “most likely” Sand rather than Pale Martin, but that northern and eastern races of Pale Martin have longer wings than the nominate form. E.g. max wing length for R.d.gavrilovi = 109.3mm; for R.d.transbaycalia = 108mm; and for R.d.tibetana = 110mm! Loskot concludes that “the zone of overlap in extreme values of wing length in R. riparia and R. diluta is exceedingly wide, and the diagnostic value of this character is low.”

From birds measured in the hand in Hong Kong and Singapore, Pale Martin R.d.fohkienensis and Sand Martin have shown a range of wing lengths of 99 – 101mm and 105 – 106mm respectively (P R Kennerley, pers. comm.).

Wells’s measurements of 14 birds identified as R.riparia ijimae, including some from S Myanmar and Tenasserim, showed a range of wing length of 100 – 106mm for adults and as short as 95mm for first winter birds (Wells 2007). At least some of these birds may have been measured before Pale Martin was recognised as a full species.

Tarsal Feathering

In an examination of 60 skins of Pale Martin (of the races diluta, gavrilovi and tibetana) and 175 specimens of Sand Martin (of the races riparia, kolymensis, ijimae and taczanowskii), Loskot (2006) found that every specimen (both juvenile and adult) could be identified to species level based on the extent of tarsal feathering, and that the character did not show significant individual or geographic variation. He described the difference as follows:

 Sand Martin:

“In some specimens of R. riparia, one or two small feathers may be present above the feather tuft near the base of the hind toe, but these never reach the middle of the tarsus, and the upper half of the tarsus always remains bare.”

 Pale Martin:

“Abundant feathers on the hind and inner sides of the tarsus, the feathers extend from the upper part of the base of the hind toe to the ankle joint where they merge with the feathers of the fibula, either continuously or leaving a small bare area usually in mid tarsus”

Loskot considered that, after plumage colour (the differences in which are probably insignificant when comparing R.d.fohkienensis and R.riparia ijimae), “tarsal feathering is one of the most important diagnostic characters.”

A photo of the tarsus of a fohkienensis Pale Martin in the hand in Hong Kong shows tarsal feathering as described by Loskot – extensive feathering from the base of the hind toe up the rear and outer side of the tarsus, a small bare patch in mid-tarsus, and less extensive feathering from the upper tarsus to the tibia.

Thanks to:

Geoff Carey and Paul Leader in Hong Kong for sharing photos, notes and expertise without which I could not have got as far as I have on this topic; Peter Kennerley for additional notes on Hong Kong birds, his Sand Martin records in Singapore, and pointing out the Alula paper; David Wells for additional info on the birds referred to in his book. Thanks also to Stuart Price (Hakodate Birding), who gave me the magic key to finding photos of ijimae Sand Martin on the web – (ショウドウツバメ)! Apologies to those I have forgotten – please remind me!

References

Cramp, S., Simmons, K. E. L., and Perrins, C. M., 1995.  Birds of the Western Palearctic

Goroshko, O.A., 1993. Taxonomic status of the Pale (Sand?) Martin Riparia (riparia?) diluta (Sharpe & Wyatt, 1893). Russ. J. Orn. 2 (3): 303-323. (In Russian.)

Loskot, V.M. 2006. Systematic notes on Asian birds. 61. New data on taxonomy and nomenclature of the Common Sand Martin Riparia riparia (Linnaeus, 1758) and the Pale Sand Martin R. diluta (Sharpe & Wyatt, 1893) in Zoologische Mededelingen, 80 (December 2006).

MNS-Bird Conservation Council, 2005. A Checklist of the Birds of Malaysia, Malaysian Nature Society

Robson, C., 2002. A Field Guide to the Birds of South-east Asia, New Holland, UK

Robson, C., 2008. A Field Guide to the Birds of South-east Asia, New Holland, UK

Schweizer, M. and Ayé, R. 2007. Identification of the Pale Sand Martin Riparia diluta in Central Asia. Alula 4. 2007. Pp152-158.

Wells, D.R. 2007. The Birds of the Thai-Malay Peninsula. Volume Two: Passerines. London: Christopher Helm.

Next post: Photos of ijimae Sand Martin and fohkienensis Pale Martin on the web

Advertisements

One thought on “Riparia martins in Malaysia: What are they? (Part 1)

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s