Differential exploitation of a single dominant prey species by migratory shorebirds – a preliminary observation from the vulnerable sandy beaches of the southwest coast of India

Abstract

Observations on the food resources of migratory shore birds in selected sandy shores of Kerala on the southwest coast of India revealed that their main prey resource is a single species of sand crab (mole crab), Emerita holthuisi Sankolli, 1965, the major crustacean resource in the narrow stretches of sandy shores of central Kerala. Three sandy beaches flanking tidal estuaries, abundant in shore crabs, were selected as the representative sites to study in detail the feeding of shorebirds on the sand crabs. We observed the presence of mole crabs for a year and noted that they are found almost year round on these shores. The shore birds were found to exploit them during their wintering months from October to February. The variations in adaptations of 8 species of predatory shore birds in preying on E. holthuisi were also noted. The same predator-prey relationship was observed in similar small stretches of sandy shores in other parts of central Kerala also.