Oriental Reed-warbler

Oriental Reed-warbler Acrocephalus orientalis is a common passage migrant and non-breeding visitor to Borneo. It is a plain olive-brown warbler, slightly smaller than the Yellow-vented Bulbul Pycnonotus goiavier.

It is a skulking bird, clambers around and feeds on insects in thick vegetations.

There is a very similar looking but much shyer and rarer Clamorous Reed-warbler Acrocephalus stentoreus occuring in southern Borneo. According to the current available field guides, this species has whiter throat, no fine streaking on throat or upper breast, has yellow gape instead of pink and has no pale tip on tail.

However, my review of images of both species at Oriental Bird Images (OBI) database shows that they are very  similar looking and hard to distinguish in the field. Per the OBI images, Oriental Reed-warbler can also have no streaking on throat and upper breast. Clamorous Reed-warbler can also show pale tips as well as non-yellow gape.

Separating Oriental from Clamorous was not as easy as the field guides led us to believe, the most accurate way to separate them is by comparing their wing formula. For Clamorous Reed-warbler, the second primary,  counted from the outside, (P9) is shorter than the fifth primary (P6). However, the P9 is equal or longer than P6 in Oriental Reed-warbler. However, most of us do not have the luxury of holding the bird in hand to do the comparison. But in Sabah we can safely identify the bird as Oriental Reed-warbler unless positively proven otherwise, as Clamorous was never recorded in Sabah.  It was only positively recorded in Kalimantan so far. The northernmost records in Borneo were in Brunei from birds seen and heard  in June 1984, presumably too late for the migratory Oriental Reed-warbler (Clive F Mann).

These images were captured in Tawau in December, next to Mr. Ku Kok On's house not far from the coast. It is my number 305 photographed wild birds of Borneo.

 

  

  

Happy birding.

Photodocument of Wild Birds of Borneo #305

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Nordmann's Greenshank

Ang Pow for the year of the Tiger comes in green! My last year Ang Pow bird was the endemic Borneo Bristlehead (Pityriasis gymnocephala), which is an unmistakable red bird.

Nordmann's Greenshank (Tringa guttifer), a rare vagrant to Borneo, with very few records. In The Birds of Borneo - An annotated Checklist by Clive F Mann, he  listed 10 records only from Borneo dating from as early as 1913 to the latest in 2006. The only records from Sabah are a few sightings from Papar in the 1960s.

Nordmann's Greenshank is a threatened species (ICUN status: Endengered) with a very small world population estimated at only 500-1,000 individuals and decreasing. This scarce species breeds in coastal eastern Russia and winters as far south as South-East Asia and Australia (BirdLife International 2009).

Although often perceived to be difficult to distinguish from the Common Greenshank (Tringa nebularia) in winter plumage, however, once acquainted, it is not hard to spot their distinctive features to isolate them out from Common Greenshank. 

The distinctive features are its bicolored, thick looking bill; shorter yellower legs; hunched appearance produced by a heavy-breast;  pale-ash-grey upperparts feathers which are narrowly fringed white, and the tertials which are not notched balck-and-white.

Two individuals were spotted and photographed at Tinagat, Tawau on 7th February 2010. I was extremely lucky as the tide was just receding when we reached the sea side, the still quite high water level brought them nearer to the shore, if our timing was out and the water level was too low, they would be miles out in the mud, or alternatively  if the water level was too high, they would have no place to land and hence would not be recorded.

This is my  number 304 photographed wild birds of Borneo.

Here are the pictures of the birds, less than 1,000 worldwide, and latest record and first ever photograph from Sabah.

The hunched appearance of the birds is apparent.

 

Enlargement of the above picture, showing the lack of 

notched tertials of Nordmann's Greenshank.

  

The tertials of Common Greenshank.

Happy birding.

Photodocument of Wild Birds of Borneo #304

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Slaty-breasted Rail

Most rails are secretive birds of the marshes, difficult to observe as they quickly run for cover in the reed-beds or wet thickets when disturbed. 

There are two races of Slaty-breasted Rails Gallirallus striatus in Borneo, the northern race  G. s. striatus dark both above and below, perhaps especially dark in juvenile plumage, from the Philippines and Sulawesi to Sabah;  and the southern race G. s. gularis  a much paler bird with whitish throat from Yunan and Indochina to Sumatra, Java and Bali. The boundary separating the two forms in Borneo is unknown.

This could also be a possible winter visitor, one (possible migrant) entered a house at night in Bandar Seri Bagawan, Brunei , 16th January 1987 (Clive F Mann).

This bird is recorded in all provinces of Borneo, but its skulking nature undoubtedly results in under recording. True to its nature, this is the first time I have seen it and it is my number 303 wild bird of Borneo.

Slaty-breasted Rails Gallirallus striatus striatus of Northern Borneo.

Happy birding.

Photodocument of Wild Birds of Borneo #303

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