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Little Egret swallowing a prawn

on 19th January 2010

William Ip photographed a Little Egret (Egretta garzetta) catching and swallowing a prawn head-first.

The prawn is covered with a continuous thin and flexible exoskeleton giving it protection without sacrificing mobility. This exoskeleton is periodically cast off through moulting as growth of the body proceeds. The new exoskeleton remains soft for some time before it hardens as calcium carbonate is deposited. As such, newly moulted prawns, as with other crustaceans are soft and vulnerable.

The prawn has no sharp spines as in fish. Instead, it has a sharply pointed rostrum that arises from the front end of the carapace, the tough covering of the head.

The Little Egret swallowing the prawn with the rostrum pointing inwards apparently causes no or minimum damage. And if the prawn has just moulted, there should be no possibility of injury. Once swallowed, the highly efficient digestive system would deal with the entire body except the exoskeleton. This would be compressed by the crop and eventually cast as a pellet.

Local photographers have recently documented pellet casting in owls, bee-eaters, shrike and kingfishers. However, so far, no one had photographed a heron casting a pellet, let alone observing one doing so.

If you like this post please tap on the Like button at the left bottom of page. Any views and opinions expressed in this article are solely those of the authors/contributors, and are not endorsed by the Lee Kong Chian Natural History Museum (LKCNHM, NUS) or its affiliated institutions. Readers are encouraged to use their discretion before making any decisions or judgements based on the information presented.

YC Wee

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

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