Asian openbill stork (anastomus 7 oscitans), Not a "Nutcracker": A study from kole wetlands of Thrissur, Kerala

Abstract

Birds are considered as an indicator of environmental health. The Asian openbill stork (Anastomus oscitans) is a large wading bird and belongs to the family Ciconiidae under the order Pelecaniformes. This paper deals with the food and feeding behavior of Asian openbill storks in Kole Wetlands of Thrissur, Kerala, India. Observations on feeding behavior were made with the help of spotting scope (10-45×), stopwatch, Sony HDR videocam, and binocular (7×50). The observation was made between 06.30 and 18.30 h, and the entire day was divided into four time intervals: morning (06.30-09.30), midday (09.30-12.30), afternoon (12.30-15.30), and evening (15.30-18.30). Focal-animal sampling method and direct observation method were used for studying the food and feeding of Asian openbill stork. September-January was the most active season for openbill storks. Feeding activity was highest during morning (06.30-09.30) and evening (15.30-18.30) hours. Asian openbill stork feeds on molluscs mainly snail Pila globosa (genus Pila) and freshwater mussel (genus Unio). Prey-capturing success was more through multiple probing. Detachment of Pila takes place underwater, but in the case of Unio, it occurs in land. Crushing of shells and feeding on fishes by openbill stork were not supported from our observations from Kole Wetlands.