Population of Waterbirds in the Breeding Colony at Khuan Khi Sian, Thailand’s First Ramsar Site

Abstract

This study investigated the species composition, population size
and population fluctuation of waterbirds in Melaleuca swamp forest at
Khuan Khi Sian, Thale Noi Non-hunting Area, Phatthalung Province,
southern Thailand. The study was conducted from April 1998 to March
1999. The number of waterbirds was counted monthly and some environmental
factors were also observed. It was found that the Melaleuca
swamp forest was a breeding site of five species of waterbirds, consisting of
Phalacrocorax niger, Ardea purpurea, Bubulcus ibis, Egretta garzetta and
Nycticorax nycticorax. This area was also served as a night roosting site for a
rare migratory species, Threskiornis melanocephalus from April to July. The
population density of waterbirds in the breeding colony greatly fluctuated
throughout the year, but peaked in May when the number reached 20,430
individuals. The lowest number was 136 in September. Of all the waterbirds,
only P. niger and A. purpurea used this breeding area throughout the year.
Considering environmental factors, the number of B. ibis, N. nycticorax and
T. melanocephalus showed correlations with mean temperature, relative
humidity and total rainfall.