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Wednesday, 31 October 2012

Wasan Rice Fields

We had a day off work Friday because of the Eid-al-Adha holiday, which offered me a great opportunity to drive down to Wasan. I have only been there a couple of times in the past. The Wasan rice fields cover an area of roughly 5 square kilometers and form Brunei's biggest agricultural development. The place is ideally suited for migrating birds that prefer paddy & fresh-water habitat. Some exceptional historical records for Borneo come from Wasan; northern lapwing, grey-headed lapwing and black-collared starling have all been seen here in the past.

Unfortunately Wasan is still a good hour drive from Panaga, otherwise I'd probably visit more often. I still managed to arrive quite early and was greeted by a pair of overflying wandering whistling ducks. Two weeks ago a number of rusty-rumped warblers were observed by Merijn. And at my first stop, next to a little stream, 3 warblers showed themselves within a couple of minutes. Too briefly for any positive ID's though - and my knowledge of migrant warbler songs and calls clearly needs updating.

When I returned with camera, one bird in particular provided some nice photo opportunities, despite the poor light. But what was it?
Even though the flank feathers are disturbed (the bird was picking at it while I was observing) the streaky appearance of the black droplets seems limited to the breast only. Luckily I got some more pictures to confirm a correct ID.
Same bird: rusty-rumped warbler (Locustella certhiola)
Note that white tips to the tail, which are a key diagnostic of rusty-rumped, are not very clear. Two other details however allow an undisputed ID:
  1. The very prominent white tip/spot at the inner web of the tertials.
  2. The blackish band in the tail feathers.
These two features clinch the ID: a rusty-rumped warbler, also known as Pallas's grasshopper warbler (Locustella certhiola). The streaking on the breast and the heavy black streaks on the rump suggest that this is a first calendar-year bird - many thanks to Kolbjorn and his Norwegian friends for pointing that out and general discussion on identification!
Rusty-rumped warbler (Locustella certhiola), with the distinct features.
Unfortunately the other warblers didn't provide any photo opportunities. This greater coucal flew into view while I was trying to get some more warbler pictures. Initially I had identified this bird as a lesser coucal, but someone kindly pointed out this bird actually must be a greater coucal. The red iris, heavy bill and strong convex culmen are diagnostic. Thanks Dave!

Greater coucal (Centropus sinensis)
During winter time the Wasan rice fields are also home to large flocks of wood sandpiper. I didn't see as many as last year, but there were still several hundreds around. Besides some common sandpipers I didn't see any noticeable other waders, nor any signs of the lapwing that was seen a week ago...
Wood sandpiper (Tringa glareola)
There were also plenty of yellow wagtails around.
Yellow wagtail (Motacilla flava)
Much to the annoyance of the local farmers, the area also holds big populations of munia's and related seed-eaters; chestnut-, dusky- and scaly-breasted munia are all abundant. A specialty of the Wasan rice fields are the Java sparrows. These birds originate from Bali and Java and are an introduced species in Borneo. In spite of all the ingenious scare crows the farmers employ -and unfortunately I also did see a couple of nets- these birds are doing extremely well and are impossible to miss.

Juvenile java sparrow (Lonchura oryzivora)
Adult java sparrow (Lonchura oryzivora)
Wasan is a place with great birding potential in the winter time to see some rare migrants and I am fully planning to visit a couple more times this season!

Folkert, 31/10/2012


  1. I wonder if this Pallas' Warbler is not a fledgling! The tail feathers look to be of relatively even length, so maybe therefore still growing and not in moult. I will forward this to birders with more Locustella experience than I have.

  2. Excellent pictures of the warbler.

  3. Had to update text, as lesser coucal was really a greater coucal. Thanks to Dave (check his excellent blog: for pointing this out.