Painted Stork eats filamentous algae

posted in: Feeding-plants | 4

Khng Eu Meng visited the Bundala National Park in Sri Lanka recently where he encountered some Painted Storks (Mycteria leucocephala) foraging in shallow water there. What was interesting was that the storks were scooping out from the water chunks of filamentous algae, to awkwardly manipulate them into their mouth for swallowing. Aware that storks eat fish and crustaceans mainly, Eu Meng instinctively knew that there was something unusual in what he observed and took the above photograph.

Storks of the genus Mycteria forage mostly in the shallow waters of lakes, marshes, riverbanks, paddyfields and sometimes even along coastal shores. They are exclusively carnivorous, eating mostly fish and occasionally frogs, reptiles, crustaceans and insects. According to Elliott (1992), plant matter may be ingested by accident, especially when it gets entangled with the prey. But there is no report that they regularly take plants. This feeding behaviour is obviously a new record for the Painted Stork.

Khng Eu Meng
Singapore
March 2013

Reference:
Elliott, A., 1992. Family Ciconiidae (Storks). In: del Hoyo, J., A. Elliott & J. Sargatal (eds.), Handbook of the birds of the world. Vol. 1. Ostrich to Ducks. Lynx Editions, Barcelona. Pp. 436-465.

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4 Responses

  1. Lee Chiu San

    I am putting forward an unproven hypothesis as to why the storks are eating the algae. As a fish keeper with outdoor ponds, I am plagued by filamentous algae. This stuff forms tangled mats, often infested with lots and lots of water snails. Plus tadpoles, fish fry and other living things.

    Keepers of African cichlid fishes from the Great Rift Lakes know that various species of these fishes constantly graze off the algae cover on rocks. The debate is still ongoing as to whether the algae is their primary source of nourishment, or is it only a secondary source, and that they crop and swallow large quantities of it mainly to consume the micro-crustaceans that live within it.

    While it has been recorded that Painted Storks are primarily carnivorous, could it be that they are swallowing the algae simply because it is a carrying agent, and that their main objective is to consume the animate organisms inhabiting it?

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  2. Great observation. Also consider that it could be closer to the breeding season and that it could be a food necessary for reproduction.
    According to Avery (1980), “Apparently Sharp-tailed Munias (Lonchura striata) eat Spirogyra as a source of protein to enable them to become physiologically ready for breeding….”

    Amar

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    • Munias may take spirogyra as a source of protein. After all, they are mostly seed-eaters and seeds are generally low in protein as compared to meat. Storks on the other hand are carnivores and I assume their normal diet provides them sufficient protein.

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