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First records of White-browed Crake (Porzana cinerea) for Laos and its current range in Southeast Asia.

Article Excerpt
The White-browed Crake (Porzana cinerea) inhabits well-vegetated lowland nonflowing wetlands from Southeast Asia east through New Guinea and Australia to Polynesia (Taylor 1996, 1998). Historical records in mainland Southeast Asia are from Malaysia, Singapore, and Thailand south of 8[degrees] N (Robinson and Chasen 1936) or "south of the Isthmus of Kra [~10[degrees] 30' N]" (Deignan 1963). On 5, 8, and 11 March 2000, TDE (Robson 2000) discovered this crake (up to three birds) in Laos, at Nong Pen, Vientiane Municipality. JWD conducted 12 monthly boat-based surveys in this area in a 20-month period: December 2003; February, April through June, and August through November 2004; and January, March, and July 2005, and found the White-browed Crake to be resident. The species is distinctive and observations were often close, prolonged, and in good light. The diagnostic white supercilium was conspicuous even on birds seen only in flight, allowing many flushed birds to be identified. The objective of this paper is to describe observations at Nong Pen, Laos and discuss recent distributional records of the White-browed Crake in Southeast Asia.

OBSERVATIONS

Nong Pen (Fig. 1) expands greatly in area and depth during the wet season (May-Oct) from its dry-season area of ~500 ha. Its water surface is mostly vegetated with lotus (Nelumbo nucifera). Smaller-stemmed and -leaved species, commonly including the aquatic fern Salvinia cucullata and the dicotyledon Ludwigia adscendens (both native to Laos: Carlsson et al. 2004b) form thick floating mats. Two invasive exotics, water-hyacinth (Eichhornia crassipes) and water-lettuce (Pistia stratiotes), are not yet present; the former abounds in some Vientiane sites, the latter less so. In the shallower parts of Nong Pen are many beds of emergent grasses and sedges. Non-native giant mimosa (Mimosa pigra) infests much of the margin. Plant growth is rapid from May onwards, giving much of the lake a dense swampy nature, which lasts well into the dry season. In December, vegetation starts to die back, and heavy human collection of plant and animal material (for food), much from wooden canoe, destroys much of the macrophyte growth. By February 2004 there was little cover and in April 2004 and March 2005, there was none on the lake itself. The floating mats were thin and compacted, with no projecting stalks; the out-of-water lotus persisted only as many dead, leafless, stalks, and marginal vegetation was trampled and grazed by water buffaloes (Bubalus bubalis).

[FIGURE 1 OMITTED]

Each morning visit during 2003-2005 involved 2 hrs in a wooden canoe, specifically searching for skulking marsh birds such as rails. White-browed Crakes were seen in all months except April (3 Jan 2005, five birds; 16 Feb 2004, nine; 6 Mar 2005, one; 5 Apr 2004, zero; 14 May 2004, three; 7 Jun 2004, three; 8 Jul 2005, eight; 26 Aug 2004, five; 14 Sep 2004, two; 8 Oct 2004, one; 7 Dec 2003, three), although the sole bird seen in November (17 Nov 2004) could not be 100% certainly identified as this species. Most birds were foraging on floating Salvinia mats, close to concentrations of...