Flexural stiffness of feather shafts: geometry rules over material properties

• DOI: 10.1242/jeb.059451
• Publication Date: 2012-01-12T18:35:38Z
• Authors: Thomas Bachmann; Jens Emmerlich; Werner Baumgartner; Jochen M. Schneider; Hermann Wagner
• Keywords: Barn

Flight feathers of birds interact with the flow field during flight. They bend and twist under aerodynamic loads. Two parameters are mainly responsible for flexibility in feathers: elastic modulus (Young's modulus, E) material (keratin) geometry rachises, more precisely second moment area (I). independent methods were employed to determine Young's feather rachis keratin. Moreover, bending stiffness shafts from fifth primaries barn owls (Tyto alba) pigeons (Columba livia) calculated. These species comparable body mass but differ wing size flight style. Whether their underwent an adaptation was previously unknown. This study shows that no significant variation between two exists. However, differences proximal distal regions found both species. Cross-sections pigeon rachises particularly well developed rich structural elements, exemplified by dorsal ridges a well-pronounced transversal septum. In contrast, cross-sections owl less profiled had higher area. Consequently, calculated (EI) as well. The results show flexural is predominantly influenced rather than local properties.