Order: Ciconiformes

Family: Ciconidae

 

Size:  up to 76 - 81 cm

 

Key Features:  predominantly greyish white with glossy black wings and tail that have a green or purple sheen. The name is derived from the distinctive gap formed between the recurved lower and arched upper mandible of the beak in adult birds. Young birds do not have this gap. The cutting edges of the mandible have a fine brush like structure that is thought to give them better grip on the shells of snails. The mantle is black and the bill is horn-grey. At a distance, they can appear somewhat like a white stork or Oriental stork. The short legs are pinkish to grey, reddish prior to breeding. Non-breeding birds have a smoky grey back instead of white. Young birds are brownish-grey and have a brownish mantle.

 

Voice: they are silent except for clattering produced by the striking of the male's bill against that of the female during copulation. They also produce low honking notes accompanied by up and down movements of the bill when greeting a partner arriving at the nest.

 

Breeding: The breeding season is after the rains, during July to September in northern India and November to March in southern India and Sri Lanka. They may skip breeding in drought years. They breeds colonially, building a rough platform of sticks often on half-submerged trees (often Barringtonia, Avicennia and Acacia species), typically laying two to four eggs. Males may sometimes form polygynous associations, typically with two females which may lay their eggs in the same nest.

 

Diet:  feeds mainly on large molluscs, especially Pila species. They also feed on water snakes, frogs and large insects.

 

Habitat: usual foraging habitats are inland wetlands and are only rarely seen along river banks and tidal flats.

 

Habits: forages at wetlands, reaching them by flying with wing flapping interspersed with gliding. During the warmer part of the day, they also soar on thermals and have a habit of descending rapidly into their feeding areas. Groups may forage together in close proximity in shallow water or marshy ground on which they may walk with a slow and steady gait. They forage for prey by holding their bill tips slightly apart and make rapid vertical jabs in shallow water often with the head and neck partially submerged. The gap in the bill is not used for handling snail shells and forms only with age. Young birds that lack a gap are still able to forage on snails. It has been suggested that the gap allows the tips to strike at a greater angle to increases the force that the tips can apply on snail shells.

 

Conservation Status: Least Concern on the IUCN Red List of Threatened Species.

 

 

 

 

 

References:

Gosner KL (1993). "Scopate tomia: an adaptation for handling hard-shelled prey?". Wilson Bulletin 105 (2): 316–324.

 

Ali S and Ripley SD (1978). Handbook of the Birds of India and Pakistan. Volume 1 (2 ed.). New Delhi: Oxford University Press. pp. 95–98.

 

Baker, ECS (1929). The Fauna of British India. Birds. Volume 6 (2 ed.). London: Taylor and Francis. pp. 333–334.

 

Blanford WT (1898). The Fauna of British India. Birds. Volume 4. London: Taylor and Francis. pp. 377–378.

 

Datta T and Pal BC (1993). "The effect of human interference on the nesting of the openbill stork Anastomus oscitans at the raiganj wildlife sanctuary, India". Biological Conservation 64 (2): 149–154

 

Photo Courtesy

JJ Harrison, Licensed under CC BY-SA 3.0 via Wikimedia Commons