Emlen funnel

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Emlen funnel

The Emlen funnel (engl. Emlen funnel ) is an apparatus by which the activity and the pulling direction of captured migratory birds during the Zugunruhe can be determined. The cage developed by Stephen T. Emlen and John T. Emlen in 1966 uses ink as the marking medium, while modified versions of typewriter correction paper, so-called tip-ex paper, or thermal paper are used.

functionality

The caught bird is placed in the Emlen funnel, which is covered with a net at the top. The funnel should not be made of ferromagnetic metal, as it interferes with the earth's magnetic field , which is important for the bird 's orientation . When jumping up in the funnel, the birds leave clear traces through the ink or as scratch marks on the Tipp-Ex paper, which can be evaluated with regard to the direction of orientation and the frequency of activity.

In contrast to electrical registration cages, the Emlen funnel is especially optimized for outdoor use.

history

The Emlen Funnel was developed by Stephen T. Emlen and John T. Emlen and was first published in the scientific journal The Auk in 1966 . In 1979 J. Rabøl described a modified variant in which, instead of the ink that soiled the bird, Tipp-Ex paper was used, on which the bird left scratches instead of stains. In 2009 Manuela Zapka and others replaced the Tipp-Ex paper, which is hardly available today because of the now rare typewriters, with thermal paper in order to make the traces recognizable.

supporting documents

  1. ↑ a b Stephen T. Emlen, John T. Emlen: A technique for recording migratory orientation of captive birds. Auk 83; Pp. 361-367. ( PDF )
  2. ^ J. Rabøl: Migrating orientation in night-migrating passerines. Ornis Scandinavia 10, 1979; Pp. 69-75.
  3. ↑ Manuela Zapka, Dominik Heyers, Christine M. Hein, Svenja Engels, Nils-Lasse Schneider, Jörg Hans, Simon Weiler, David Dreyer, Dmitry Kishkinev, J. Martin Wild, Henrik Mouritsen: Visual but not trigeminal mediation of magnetic compass information in a migratory bird. Nature 461, October 2009; Pp. 1274-1277. ( Abstract )

literature

  • F. Nievergelt, F. Liechti: Methodical aspects for the investigation of the train activity in the Emlen funnel. Journal of Ornithology 141, 2000; Pp. 180-190. ( PDF , doi: 10.1007 / BF02462250 [correction])