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Owl bulge (bar = 1 cm)

The indigestible food remains ( bones , feathers ) that are choked out by owls and birds of prey , but also by many other bird species, are called bulges or spits .

Depending on the species of bird , the vault contains fish bones , skeletal parts, parts of snail shells , mussels and crustacean shells as well as chitin parts from insects . In birds of prey and owls, these are usually wrapped in mammalian hair or feathers.

The examination of the components of the vault gives the zoologists important information on the prey animals that were eaten by the respective birds. Investigations of the vaults provide information about the fauna in the hunting area of the animals.

Birds producing vaults

The following groups of birds or species produce Gewölle (selection): Owls , turncoat , cormorants , birds of prey , herons , gulls , apodiformes , Kingfishers , shrikes , cuckoo , some thrushes , crows and ravens , waders , corncrakes , bee-eaters , Kagu and storks .


  • R. March: Growing and plucking studies. Akademie-Verlag, Berlin 1987, ISBN 3-05-500157-5 . (Determination of bones and feathers)
  • W. Meyer, G. Hülmann, H. Seger: SEM atlas on the hair cuticle structure of central European mammals. M. & H. Schaper, Hannover 2002, ISBN 3-7944-0200-6 . (Determination of hair)
  • BJ Teerink: Atlas and identification key: Hair of westeuropean mammals. Cambridge University Press, Cambridge / New York / Port Chester / Melbourne / Sydney 1991, ISBN 0-521-40264-6 . (Determination of hair)
  • B. Wuntke, O. Müller: Vertebrates in the vaults of the barn owl, identification key for vault examination. German Youth Association for Nature Observation , Hamburg 2002, ISBN 3-923376-23-5 .

Web links

Commons : Vaults  - collection of images, videos and audio files