FORAGING ECOLOGY OF THE CRESTED DRONGO (Dicrurus paradiseus lophorhinus) IN THE SINHARAJA WORLD HERITAGE RESERVE

Abstract

Preliminary study o f Foraging Ecology o f Crested Drongo in the mixed-spices bird flocks was carried out in the Sinharaja World Heritage site The crested Drongo Dicrurus paradiseus lophorhinus belong to the Family Dicruridae, is known to be a key member o f mixed foraging flocks, A flumber o f studies have been carried out on the mixed foraging flocks o f Sinharaja and However, there have been no studies o f the foraging ecology of Drongos in Sinharaja,Henee, this information is an important missing piece o f our understanding of the Sinharaja flock system. The study aimed to identify whether Crested Drongos kleptoparacitize, consume insect species disturbed by other birds. Change their perching behaviour based on the presence of other birds. And whether they feed more inside or outside o f flock. Hypothesis was derived based on the above questions. The methodology identified the study area initially. The study was conducted 10* February 2005 to 27 April 2005. A sampling strategy was decided and executed in seven sampling area as defined by the experimental design to obtain some selected parameters and data on the rote f the crested Drongo within flocks. The observations were made using with binoculars,while tape recording the birds5 vocalizations. In total, 597 observations were made o f the Crested Drongo in the 1588 minute used Adlibitum sampling method. Data analysis was conducted separately for the different questions Usted in the Objectives. According to the results kleptoparasitism is a rare but consistent tactic of Drongo and the nature o f the event defer according to the species subjected to it. About 466 - 605 observations were made o f Drongo foraged in mixed-species birds5 flocks. Although kleptoparasitism occurred only 4% o f the total observations and it was seen at all seven sites. A significant percentage o f the foraging o f the Drongos appears to be on insect disturbed by other birds, in 63% o f our 488 observations. The relationship between Drano’s, Orange-billed Babbler and Ashy-headed Laughing-thrush the overall relationship was provided extremely strongly significant relationship is significant for tow o f the site, overall relationship is inverse Orange-billed Babbler and much less strong significant. .Drongo forage more inside flock than out side as expected. The rate o f sallying and hovering trip is in nearly six times more inside flocks than out side o f them. Overall conclusion the data makes it evident that Crested Drongo Dicrurus paradiseus lophorhinus) benefits by association with flocks. That they adjust their feeding in flocks to take advantage o f insect disturbed by other species (change their foraging height with Ashyheaded laughingthrushes) and they sometime or rarely kleptoparasitism other species implicating some cost on the birds they associate with.