ECOLOGY OF THE ORIENTAL DARTER (ANHINGA MELANOGASTER PENNANT, 1769) IN PHU KHIEO WILDLIFE SANCTUARY, CHAIYAPHUM PROVINCE

Abstract

The study of the ecology of the oriental darter in Phu Khieo Wildlife Sanctuary, Chaiyaphum Province was conducted from April 1998 through April 1999. The objectives were to study behavior, habitat prey, population, and threats for the management of the species. The results indicated that the oriental darter spent the greatest time for resting and roosting on dead trees in a pond. During the hot days it stayed in live trees thickly covered with vegetation. The oriental darter fed by diving around a floating weed or in standing water. The depth of standing water used was between 0.9-1.7 m. Predation occurred primarily during 3 time intervals: early morning before 7.00 a.m., late morning between 10.00-12.00 a.m. and in the afternoon between 13.30-16.00 p.m. The duration per preying event lasted between 6 min. to 3 hrs. and 21 min. (average I hr. and 7 min.) with total distance from start to finish between 10 m.-200 m. (average 162.5 m.). It used 2 methods for eating : using the beak to hold in the mouth or using the beak to pick through prey before throwing it in the air and swallowing. The dominant species of prey were little fishes in the family cyprinidae. After eating it preferred to dry its wings on a stump up to 30 m. height of dead trees. The time for this activity lasted between 5 min. to 1 hr. and 7 min. (average 20.07 min), There was a population of at least 2 individuals, and it is thought to be a migrant breeding bird between upper and central Thailand or of the upper and central Indo-Chinese region. The occurrence of the oriental darter is determined by temperature, with migration occurring during low temperatures. The oriental darter did not display aggressive behavior towards different species but did show intraspecific conflict. This study did not record displaying, breeding, nesting or carrying behavior. The oriental darter is protected by the Wildlife Preservation and Protection Act (1992), is listed as critically endangered on the Wildlife in Thailand List (1997), and as a threatened species by the IUCN (1996).