BNHS Final Report 2001-2005

Executive Summary

The four year study carried out at Chilika between 2001and 2005 has documented the status and distribution of birds in different zones of the Chilika lake. This is the first systematic study on the avifauna of this lake which has also identified the major conservation issues and suggested possible measures to mitigate the problems.  A Waterbird atlas (distribution of ducks and waders in different zones) of Chilika Lake has been made available. The breeding status of terns and waders on the Nalabana Island, the location of new wader habitats at Satapada and the current status of uncommon waterfowl species are some of the other findings of the study. Among ducks, the Northern Pintail Anas acuta  numbers exceeded 200,000, and in both Gadwall Anas strepera and Tufted Pochard Aythya fuligula the numbers were more than 100,000. A total of 225 species were recorded, including 9 threatened species. In 43 species, the number of birds recorded exceeded their 1% biogeographical poulation. The role of Chilika in maintaining the global population of major wintering waterfowl and wader species of India was recognized through population estimates of individual species.

A total of 6,161 birds of 63 species were ringed during the four year study. Out of the 5,700 waders ringed during the study period 85 were recaptured in the subsequent seasons. This suggests the existence of significant site fidelity among the wintering waders of Chilika. The major changes in the bird population of certain uncommon species from that of 1940s and 1950s have been discussed. Similar comparison has been made for the wader population of 1980s with that of the study period (2001-2005) through the percentage of individual species caught. The activities such as staging, moulting, wintering, summering, and breeding being supported by Chilika for individual waterbird species have been reasonably well documented through bird banding and breeding studies. Habitat utilization pattern and yearly shifting of bird congregations to areas that were unexploited in the preceding years were also documented. The loss of habitats (weed cover) for the local freshwater preferring bird species in the Northern Sector, and the formation of intertidal mudflats for the long distant migrant waders at Satapara region are the two possible major impacts of the hydrological intervention on bird population.

The traditional linkage between Chilika and south Indian wintering grounds established through an earlier bird ringing study, was also confirmed during this study.

 The maximum number of nests recorded for Gull-billed Tern Gelochelidon nilotica was 326 and for River Tern Sterna aurantia was 540. As the   bird congregation of Nalabana is mostly confined to a small area (9 sq. km), which is too small for the entire population (over 400,000) to forage daily, it was recommended to create an additional island.  To avoid nest damage from flooding, provisions for artificial nesting sites for terns and other ground nesting birds was recommended. Eradication of Salicornia weed is recommended to prevent further habitat (mud flats) loss for waders due to weed invasion.

Training was imparted to wildlife officials, researchers and amateurs on water bird identification and population monitoring. Two waterbird censuses (2004 & 2005) were conducted more systematically in collaboration with the Chilika Development Authority (CDA) and Wildlife Department of Orissa.

Environmental education and awareness programme for stakeholders and students to understand and promote waterbird conservation are suggested. Measures are suggested to promote scientifically planned and carefully monitored ecotourism in Chilika Lake for waterbird conservation.

While our results provide important insights, continued research is needed to further the successful conservation and management of birds of Chilika Lake. As waterbirds occupy the top of the aquatic ecosystem, measures undertaken for the conservation of these groups will benefit the other biotic components of the wetland ecosystem.