Colonial nesting of Asian openbill storks (Anastomus oscitans) in Nandankanan Wildlife Sanctuary, Odisha

Abstract

Asian openbill storks Anastomus oscitans (AOS) are the smallest among the nine stork species found in India.1,2 They are pale grey storks with black scapulars and reimages, black tail, short reddish legs and a swollen looking bill with a narrow gap between mandibles.1 Adult birds have a prominent gap between down–curved upper and recurved lower mandible as an adaptation for grasping snails which is their main prey. However young birds are born without gap in the bill.3 They are widely distributed in the plains and the peninsula of the Indian subcontinent.1,4 Although mostly resident within their ranges, these birds cover long distances in response to weather suitability and food availability for overwintering and breeding. They breed during the monsoon between July and September.5 Previous observations have also reported their congregation in nesting colonies with the onset of south–west monsoon from mid June to January.6–8 Colonial nesting site of AOS at Nandankanan Wildlife Sanctuary (NWS) is considered as second largest heronry of the state of Odisha, Eastern India with nesting report since 1999. But, information and published literatures on the nesting habits, population trend and habitat preference of AOS at NWS are inadequate and inconsistent. The present communication intended to report the details of colonial nesting habits of these storks at NWS.