Use of tidal flats in the Cauvery Delta region of SE India by shorebirds, gulls and terns

Between Oct 1999 and March 2000, we studied the use by shorebirds, gulls and terns of six tidal flats (three sandflats and three mudflats) in the Cauvery delta region of SE India (Tamilnadu and Karaikal). Altogether 26 species used the flats. Five species used both mud and sand flats (Kentish Plover, Great Ringed Plover, Dunlin, Little Tern and Whiskered Tern); twelve species used only mudflats (Long-billed Ringed Plover, Swallow Plover (= Small Pratincole), Pectoral Sandpiper, Common Snipe, Little Curlew, Whimbrel, Caspian Tern, River Tern, White Tern, Gull-billed Tern, Herring Gull and Common Black-headed Gull; but no species used only sandflats. Overall bird density was highest during Jan 2000 on all six flats except one (Thirumullaivasal). Species richness was also highest in Jan 2000. All of the flats had high species diversity values between Dec 1999 and Feb 2000 indicating that they were used by many species in relatively low numbers. Bird density, species richness and diversity showed significant variation between the months and the different sites. Mudflats had significantly higher overall density and species richness than sandflats.