Black-naped Tern: Defense vomiting

posted in: Interspecific | 6

This post on the mobbing of a Grey Heron by Black-naped Terns (and associated images) has been incorporated into the publication below. Get a PDF copy of the paper HERE.

Deng, S. H., T. K. Lee & Y. C. Wee, 2008. Black-naped terns (Sterna sumatrana Raffles, 1822) mobbing a grey heron (Ardea cinerea Linnaeus, 1758). Nature in Singapore 1: 117-127.

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6 Responses

  1. Vomiting of stomach contents might not be an efficient strategy, especially if the species of bird feeds its chicks through regurgitation. A bird that repels predators by vomiting would then have to expend energy obtaining more food.

    Where it comes to excrement as a weapon, the fieldfare, an European species of thrush (Turdus pilaris), repels nest predators by dive-bombing and showering them with excrement.

    http://youtube.com/watch?v=Fdrl__ggV9k

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  2. Thanks Hai-Ren, most interesting. Based on your reference, I am now wondering whether the terns are using vomit or excrement? Any idea anyone?

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  3. I think its definitely excrement. Food is better saved for the hungry chicks then to be wasted on the heron.The excrement theory is more sound to me.

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  4. Hai-ren and Haniman: Fulmars (Fulmarus glacialis)feed their chicks by regurgitation and use vomit-defense. We cannot say that if it is less efficient then it wouldn’t be possible. Evolution works in funny ways! 😉

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  5. Synchronicities abound; I love it when that happens. I have been reading a library book “Birds: Their Life, Their Ways, Their World” by a Dr. Christopher Perrins (Switzerland). On page 187 of the book, in a piece regarding Petrels, is a drawing of a bird spewing at a fox. At first I thought the lines were the ‘sound waves’ often drawn to show the bird might be squawking, but the description was: “A Fulmar Fulmarus glacialis deters a predator by projecting musky stomach oil.” I thought you’d find it interesting

    There is something else I question. Don’t parent birds hold food in their crops or gullets and ‘regurgitate’ that (as opposed to stomach contents) to feed chicks? I was not of the impression they actually vomited into their youngsters. While several sites casually use the word ‘stomach’ this one says crop, which makes more sense to me.

    And…I’m betting the Petrels spew actual stomach contents; musky oil doesn’t sound like baby food. But I could be wrong.

    In this article: Muttonbirder
    selectivity
    of sooty shearwater chicks harvested in New Zealand (CHRISTINE M. HUNTER , HENRIK MOLLER, JANE KITSON) is a discussion regarding how hunters make chicks ‘spew’ stomach oil by palpating the chick…so that later their feathers are not harmed later. This seems to me evidence even chicks spew when threatened. (see Pg. 3 of the article)

    Here is another article: NEW LIGHT ON THE CAHOW, PTERODROMA CAHOW (Robert C. Murphy and Louis S. Mowbray) which mentions this behavior in Petrels. (see Pg. 7 of the article)

    And another short
    comment here
    with a photo of one in the air.

    Again…I hope this is still of interest to you; I’d never heard of such a thing.

    Beverly

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  6. Thanks Beverly. Your comments and references would have been very useful in our writeup of the mobbing for publication. Except that I manage to access it only today, the site having being down since 28 Sept. Somehow or other your comment, dated 22nd, only appeared today, must have got entangled in cyberspace until now. We have just sent the paper for publication and it is scheduled for uploading within the nest day or so. Will make an announcement in the blog.

    But the references are still extremely useful. Thanks again.

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