When birdwatching in the extreme lowlands, especially in dry dipterocarp woodland, the driest and often the hottest, and least hospitable, forest type, you are conscious of racing against the clock. You're out at first light, making the most of those precious few hours of early morning bird activity, before the great midday lull settles like a suffocating blanket. The sky is a shimmering grey haze, and not a bird moves, or can be heard above the noise of cicadas. In the hottest and driest time, February to April, the lull can descend as early as 0900 or so. Your energy flags as the bird activity dwindles and all you can think about is getting to some shade and water.

My trip to Thap Lan last year with Wachara Sanguansombat, though, was timed just right. It was mid-December, and the cool weather was beginning to make its presence felt so that conditions for working the dry dipterocarp on the park margins, near Sap Sadao Guard Station, could not have been bettered. The sky was crystal-blue and the temperatures stayed cool even up till midday, which meant one could keep going all day. It was one of those times when the birding was sublime.

If you can find good quality plains dry dipterocarp, the birding can scarcely be bettered. In the evergreen forest, you will always hear many more birds than you will ever see, and, let's face it, however exciting the birds you see, there are frequent periods of time when you see very little. But in the best plains dry dipterocarp, the birds come so thick and fast that you scarcely have time to write them all down. If this sounds hard to believe, it is probably because it is now so hard to find diverse and species-rich plains forest anywhere that few of us have even seen it. Most has been cut down and turned into farmland so that, most of the time, we are forced to salvage what we can in the hills, such as the lower slopes of Doi Inthanon, or similar sites where some lowland deciduous woodland remains. Now the day dry dipterocarp on the foothills of Doi Inthanon is not too bad: many of the characteristic bird species, such as Black-headed and White-bellied Woodpeckers and others are there, but they are scarce, and one has to work hard for what one sees. Much dry dipterocarp may be secondary, degraded from other forest types, or has had most of the large trees removed, and therefore tends to be much less rich in birds, supporting only the generalists. Some patches are so frequently and heavily burnt-over that they become dominated by stands of a single species, yang phluang ( Dipterocarpus tuberculatus ). These sites are especially poor for birds.

The best dry dipterocarp forest I have birded in was in Dong Khanthung, in the far south of Laos, in that small part of that country that lies on the west bank of the Mekong, wedged up against that Thai and Cambodian borders. This may be the last bit of Mekong floodplain habitat in Laos in anywhere near original condition, and even there it was going fast, with new villages and rice paddies opening up the woodland. But when I was there in 1998, it was still pretty good. It was the kind of area to which many people have referred as “lowland forest mosaic” in which patches of dry dipterocarp and grassy savanna alternated with mixed deciduous or semi-evergreen forest. There were many tall trees and also small patches of scrubby dense evergreen, but there were also many pools scattered among huge grassy clearings and “parkland”. Besides a great range of forest birds, especially woodpeckers, parakeets and Green Inperial Pigeons, Dong Khanthung supported populations of Woolly-necked Storks, and Lesser Adjutants, as well as the last Sarus Cranes and Giant lbises in Laos. It gave me a taste of what much of lowland Thailand and Indochina must have been like fifty or a hundred years ago. In spite of Dong Khanthung's continued richness, though, the prevailing feeling, was one of loneliness and emptiness, symbolized for me by the incessant hollow pooh-pok calls of Lineated Barbet, ringing through the woods all day long. Scarcely any large mammals were to be seen, though there were a few banteng tracks, tiger tracks and, yes, even Eld's Deer tracks, confirmed by the presence of new antlers as hunting trophes in one or two village houses. (To give you an idea how badly the once-rich megafauna of the SE Asian plains is faring, so far as I can gather these are still the only surviving Eld's Deer anyone has found in Indochina, notwithstanding the gradual opening up of Cambodia, which has a lot more wooded floodplain than any other country in the region.)

Which brings me back to dry dipterocarp at Sap Sadao. It was a tiny area, really, barely occupying more than about 4 sq. km, sandwiched between cultivation on the outer margin, and the logged semi-evergreen forest, which occupied most of the body of Thap Lan National Park. The first thing that struck me was the obtrusiveness of bird-waves, with species such as Fulvous breasted Woodpecker, Common Woodshrike, Large Cuckooshrike, Indochinese Cuckooshrike, and various minivets (various combinations of Ashy, Rosy, Brown-rumped, Scarlet and Small), and Chestnut-bellied Nuthatch forming up the body of the flock. The grassy ground storey vegetation held Burmese Shrikes and Brown Prinias among other small birds. I was also excited to see White-browed Fantails. Two or three of these charming birds were usually present in some waves, flirting around the bases of the Shorea trunks.

It seems that White browed Fantail was first found in Thap Lan by Mr.Pornchai Visuthatarn, a park official who is keen on birds. Amazingly there are no previous records of White-browed Fantail for NE Thailand (even though it has long been known to be present in S Laos (and in deed, I had previously found it in Dong Khanthung). This is a clear indication that, in Thailand, we have so much, and so rapidly, that we scarcely even know what was formerly present in any given region.

Another link with the dry dipterocarp of Indochina to the east was Streak-breasted Woodpecker, a bird I was delighted to add to my personal Thai list (having also seen it for the first time in Dong Khanthung). If you see a green- backed woodpecker in open dry dipterocarp which that is definitely not Grey-headed Woodpecker, then look at it carefully. Laced Woodpecker seldom if ever occurs in open dry dipterocarp, favouring more dry evergreen, mixed deciduous and bamboo clumps. To my ear, the call of Streak-throated is also rather different, sounding about mid-way between the keek of laced and the tchick of the Dendrocopos woodpeckers, such as Fulvous-breasted Woodpecker and this its sister species from the mountains, Stripe-breasted Woodpecker. Historically, there were no records of Streak-throated Woodpecker from anywhere other then the western margin of the country. However, a skin was collected from Sakaerat in the 1970s, adding this fine woodpecker to the fauna of the eastern plateau. But how pitifully few are left in Thailand! Will Duckworth told me that in good quality dry dipterocarp of Dak Lak Province, Vietnam, he saw maybe some tens of this species over a few days-enough to examine several pairs in detail, anyway., Iin Sap Sadao, we found just one bird!

Still , we were nonetheless highly impressed by Sap Sadao. In addition to those species already mentioned, there were flocks of Blossom-headed Parakeets screaming around; a pair of White-rumped Falcons and many other exciting or scarce birds. In addition to Streak-breasted Woodpecker I think we had another 8 species of woodpecker there: both flamebacks, both yellownapes, Fulvous- breasted and Grey-capped, Black-headed and White-bellied. Sadly, there were no Great Slaty Woodpecker, and, in surveys elsewhere in the “upper eastern forest complex”, I was generally disappointed by how scarce this largest of the world's woodpecker was anywhere. I was also hoping to find Yellow-crowned Woodpecker at Sap Sadao. This lovely little woodpecker, common in all manner of scrubby dry country in the Indian subcontinent, is known by perhaps only one, or at most two records from Thailand. Why should it be so scarce here? Well, it seems that this species too is, in Thailand and Indochina, restricted entirely to the best quality, plains dry dipterocarp. It was another species I found in Dong Khanthung, where it was the first confirmed Lao record. (Will Duckworth has also found it in Dak Lak, Vietnam, and I gather it has since been found in Cambodia). In a perverse kind of way, I think I was as excited by finding Yellow-crowned Woodpecker for Laos as I had been on seeing my first (and still the only!) Giant lbises a couple of days before. I was disappointed not to find it at Sap Sadao.

How many parks and sanctuaries still have a few ragged fragments of plain dry dipterocarp left around their margins? These are the last such vestiges of good quality plains forest left in the country, and are among the most vulnerable to encroachment. They will doubtless be among the first forest to go should Thailand's next Cabinet decide to open further forest areas to settlement by supposedly “landless framers”, or grant concessions to eucalytpus plantation companies. On our birding trips and forest hikes, we're usually in such a hurry to get into the remote hearts of the last wildernesses, that we usually speed past these marginal, supposedly less interesting areas around protected area boundaries. I myself missed many opportunities, on my frequent trips into Huai Kha Khaeng Wildlife Sanctuary in the 1980s, to inventory the birds in the dry dipterocarp which lay outside the sanctuary's eastern border, along the Huai Thap Salao. It may be too late now: although the area has since been annexed into Huai Kha Khaeng Sanctuary, this did not happen until after the 1989 logging ban, by which time it had been selectively logged by the Thai Plywood Company. Well, it may now be a bit degraded, but at least the habitat is still there, awaiting the birdwatcher who will attempt add Yellow-crowned and Streak-throated Woodpeckers, and maybe one of two other dry dipterocarp specialists, to the sanctuary list!

Philip D. Round
September 2000