BREEDING BIRDS AT KUMANA VILLU OF YALA EAST NATIONAL PARK: STATUS AFTER 22 YEARS

Abstract

Kumana villu is one of the oldest known breeding sites for many waterbirdspecies that breeds colonially. The canopy of mangrove trees located insidethe villu provides nesting facilities for the large water birds such as Paintedstorks, Spoonbills, Black headed Ibises, egrets, cormorants and globallythreatened Spot billed Pelicans. A detailed study of this breeding colony wasdone in 1983 By Kotagama. After 22 years, the breeding bird survey wasreinitiated in July 2005.

First, a roosting count was done to estimate the population size of breedingbirds in the Kumana villu. The counts were conducted from 3 pre-identifiedlocations between 1700 to 1900h in the 2nd week of July. Three mangrovevegetation patches of 5000m2 were chosen for a detailed nest count. In eachpatch, the number of trees used for nesting was recorded. Then for each tree,number of nests, the species to whom the nests belonged, the height of eachnest and the current status of nesting were recorded.

Many species of birds use this villu for roosting while Painted Storks showedthe highest population density (728). Among other water birds, spot billedpelicans (422), spoonbills (57), cormorants (187), egrets (184), Black headedIbises (74) and darters (41) are the most common taxa. In 1983,228 paintedstorks, 565 pelicans, 125 ibises and 609 egrets were recorded. Five flightpaths of birds that come to roost were identified in 1983. However, only 3flight paths were observed during this survey.

A total of 293 nests were recorded that belonged to five species namelypurple herons, little cormorants, painted storks, spot billed pelicans andspoonbills. Most common nesting species in this period was painted stork and97.6% of their nests were still active. In May 1983, total of 701 nestsbelonged to seven species were recorded and most nests were of paintedstorks (529). In 1983, nests of four additional species, grey herons, ibises,egrets and night herons were recorded while purple herons and cormorantswere not recorded to be nesting.

The mangrove vegetation has changed from a diverse habitat to a singlespecies (S. caseolaris) stand during last 22 years. Reduction of mangrovearea was also observed. Further, invasion of the common weed species Typhaangustifolia is another major change that has taken place during this period.

Isolated mangrove trees and trees that are located beyond the perimeter of thevillu are not selected by birds for nesting. Low density of vegetation insidethe villu is a limiting factor for breeding birds. Most remaining trees in thevillu are not in good condition and therefore a replanting programme isrecommended to ensure continuous breeding of this colony.