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Diurnal species richness and diversity of aquatic avifauna at three reservoirs of the
Anavilundawa Ramsar site of Northwestern Sri Lanka was recorded using line transact method
from October 2009 to March 2010. Populations of the water birds were recorded from 7:00 hrs
to 10:00 hrs, three times each month. Twenty eight species of water birds belonging to six orders
and twelve families were recorded from Anavilundawa, Suruwila and Maiyawa reservoirs.
These included two nationally threatened species, Spot-billed Pelican (Pelecanus philippensis)
and Great Cormorant (Phalacrocorax carbo) and one winter visitor, Garganey (Anas
querquedula). Relative abundance and rank correlation indicated that Lesser Whistling-Duck
was the most common water bird species followed by the Purple Coot and Garganey. Common
Moorhen was the least common bird followed by, Little Ringed Plover and Black Bittern. Birds
belonging to Anatidae, Ardeidae, Phalacrocoracidae, Rallidae and Jacanidae families were
recorded in high numbers. Among the families recorded, Anatidae family had the highest
number of birds. Three waterfowl species belonging family Anatidae were recorded. They were,
Lesser W histling Duck (Dendrocygna javanica), Cotton Pygmy Goose (Nettapus
coromandelianus) and migratory waterfowl Garganey (Anas querquedula). Suruwila reservoir
had the highest Shannon diversity (IT) index of 2.345 while Anavilundawa had the lowest
diversity index of 2.104. Water birds diversity of the Anavilundawa reservoir differed
significantly from the Maiyawa reservoir (t = 0.140, df = 2133). However it did not differ
significantly from the Suruwila reservoir (t = 3.022, df = 3047). The diversity of water birds
between Suruwila reservoir and Maiyawa reservoir did not differ significantly (t = 2.644, df =
1840). Evenness was high in the Maiyawa reservoir (0.747) and low in the Anavilundawa
reservoir (0.638). Present study revealed that the three reservoirs of the Anavilundawa Ramsar
wetland provide an important habitat for twenty eight water bird species, and thus warrant
protection.
