summary
Owls (Strigiformes) are nocturnal birds of prey that are known for their silent flight. For a long time, the underlying mechanisms were not well understood. In a comprehensive study, we have characterized the flight apparatus of one representative of owls, the barn owl (Tyto alba pratincola), to advance beyond the phenomenological description provided so far. The barn owl wing is adapted to slow flight as indicated by a low wing loading, an elliptical shape, a high camber and a specific thickness distribution. Further, feather specializations can be found: 1.) serrations at the leading edge of the wing, 2.) a velvety dorsal surface texture, and 3.) fringes at the inner vanes of remiges. Quantitative characterizations of these structures revealed that serrations had a uniform shape, but the length depended on their position on the wing. The velvety dorsal surface texture differed between the inner and outer vanes which is a consequence of different functions (air flow control, friction reduction). The fringes were observed to merge into neighboring feather vanes by gliding into grooves at the lower wing surface to create a smooth airfoil. Besides anatomical data, material properties and wearing effects of feather keratin of rachises and barbs were obtained.
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References
Bachmann, T.: Anatomical, morphometrical and biomechanical studies of barn owls’ and pigeons’ wings. PhD thesis at RWTH Aachen University (2010)
Bachmann, T., Emmerlich, J., Baumgartner, W., Schneider, J.M., Wagner, H.: Flexural stiffness of feather shafts: geometry rules over material properties. J. Exp. Biol. (accepted, 2012)
Bachmann, T., Klän, S., Baumgartner, W., Klaas, M., Schröder, W., Wagner, H.: Morphometric characterisation of wing feathers of the barn owl (Tyto alba pratincola) and the pigeon (Columba livia). Front. Zool. 4, 23 (2007)
Bachmann, T., Mühlenbruch, G., Wagner, H.: The barn owl wing: An in-spiration for silent flight in the aviation industry? In: SPIE, vol. 7975 (2011)
Bachmann, T., Wagner, H.: The three-dimensional shape of serrations at barn owl wings: towards a typical natural serration as a role model for biomimetic applications. J. Anat. 218(6), 192–202 (2011)
Bachmann, T., Wagner, H.: Silent owl wings. In: Encyclopedia of Nanotechnology. Springer, Heidelberg (2012)
Bergman, G.: Why are the wings Larus f. fuscus so dark? Ornis Fennica 59(2-3), 77–83 (1982)
Biesel, W., Butz, H., Nachtigall, W.: Erste Messung der Flügelgeometrie bei frei gleitfliegenden Haustauben (Columba livia var. Domestica) unter Benutzung neu ausgearbeiteter Windkanaltechnik und der Stereophotogrammetrie. Biona Report 3. Gustav Fischer Verlag (1985)
Bonser, R.H.C.: Melanin and the abrasion resistance of feathers. Condor 97(2), 590–591 (1995)
Brush, A.H.: Feather keratin – analysis if subunit heterogeneity. Corap. Biochem. Physiol. 48, 661–664 (1974)
Carruthers, A.C., Thomas, A.L.R., Taylor, G.K.: Automatic aeroelastic devices in the wings of a steppe eagle Aquila nipalensis. J. Exp. Biol. 210, 4136–4149 (2007)
Chilgren, J.: Body Composition of Captive White-Crowned Sparrows during Postnuptial Molt. Auk 94(4), 667–688 (1977)
Filshie, B.K., Rogers, G.E.: An electron microscope study of the fine structure of feather keratin. J. Cell Biol. 13(1), 1–12 (1962)
Graham, R.: The silent flight of owls. J. Roy. Aero. Soc. 38, 837–843 (1934)
Inglis, A.S., Lennox, F.G.: Studies in Wool Yellowing: Part IX: Irradiation with Different UV Wavebands. Text. Res. J. 35(2), 104–109 (1965)
Ito, S.: Aerodynamic influence of leading-edge serrations on an airfoil in a low Reynolds number – A study of an owl with leading-edge serrations. J. Biomech. Sci. Engin. 4, 117–123 (2009)
Klän, S.: Experimental Analysis of the flow over an owl-based wing geometry. Berichte aus der Strömungstechnik. Shaker Verlag GmbH (2011)
Klän, S., Bachmann, T., Klaas, M., Baumgartner, W., Wagner, H., Schröder, W.: Experimental analysis of the flow field over a novel owl-based airfoil. Exp. Fluids 46(5), 975–989 (2008)
Kroeger, R., Gruschka, H., Helvey, T.: Low speed aerodynamics for ultra-quiet flight. AFFDL 71-75, 1–55 (1971)
Launer, H.F.: Effect of Light Upon Wool: Part IV: Bleaching and Yellow-ing by Sunlight. Text. Res. J. 35(5), 395–400 (1965)
Lilley, G.: A study of the silent flight of the owl. AIAA Paper 98-2340 (1998)
Mebs, T., Scherzinger, W.: Die Eulen Europas. Frankh-Kosmos Verlag (2000)
Moreau, D.J., Brooks, L.A., Doolan, C.J.: On the aeroacoustic tonal noise generation mechanism of a sharp-edges plate. JASA Expr. Lett. (2011)
Müller, W., Patone, G.: Air transmissivity of feathers. J. Exp. Biol. 201, 2591–2599 (1998)
Murozono, S., Murayama, K., Akahane, K.: Soluble proteins from fowl feather keratin. III. Isolation and characteristics of some calamus proteins. J. Biochem. 82(1), 53–58 (1977)
Murphy, M.E., King, J.R.: Energy and Nutrient Use during Moult by White-Crowned Sparrows Zonotrichia leucophrys gambelii. Ornis Scand. 23(3), 304–313 (1992)
Neuhaus, W., Bretting, H., Schweizer, B.: Morphologische und funktionelle Untersuchungen über den lautlosen Flug der Eule (Strix aluco) im Vergleich zum Flug der Ente (Anas platyrhinchos). Biol. Zentralbl. 92, 495–512 (1973)
Nicholls, C.H., Pailthorpe, M.T.: Primary Reactions in the Photoyellowing of Wool Keratin. J. Text. Inst. 67(11), 397–403 (1976)
Piechocki, R.: Über die Großgefieder-Mauser von Schleiereule und Waldkauz. J. Orn. 102(2), 220–225 (1961)
Rohwer, S., Ricklefs, R.E., Rohwer, V.G., Copple, M.M.: Allometry of the duration of flight feather molt in birds. PLoS Biology 7(6), e1000132 (2009)
Taylor, I.: Barn Owls, pp. 108–110. Cambridge University Press, Cambridge (1994)
West, G.C.: Bioenergetics of captive willow ptarmigan under natural conditions. Ecology 49(6), 1035–1045 (1968)
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Bachmann, T., Blazek, S., Erlinghagen, T., Baumgartner, W., Wagner, H. (2012). Barn Owl Flight. In: Tropea, C., Bleckmann, H. (eds) Nature-Inspired Fluid Mechanics. Notes on Numerical Fluid Mechanics and Multidisciplinary Design, vol 119. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-28302-4_6
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