Meeting Abstract

P1.150  Monday, Jan. 4  Mechanical properties of the forelimb skeleton of birds utilizing different primary flight modes SIMONS, Erin L. R.; Midwestern Univ. esimon@midwestern.edu

Mechanical testing at the whole bone level was performed on the wing elements of several bird species to address hypotheses related to the relationship between avian skeletal structure and function. Young’s modulus (stiffness) in dorsoventral bending was determined from the humerus, ulna, and carpometacarpus of three species of birds that utilize different primary flight modes: the Double-crested cormorant, a continuous flapper; the Brown pelican, a static soarer; and the Laysan albatross, a dynamic soarer. Results of this study reveal that variation exists in Young’s modulus both among wing elements within a species and among species that utilize different primary flight modes. Within all three species, the CMC and ulna are significantly stiffer than the humerus, presumably to accommodate the loads transmitted though the flight feathers. In addition, the dynamic soaring albatross and continuous flapping cormorant exhibited stiffer wing elements than the static soaring pelican. Both flapping continuously and dynamic soaring in high speed winds may cause more stress on the wing, requiring the wing elements to be stiffer to adequately resist the load. In addition, static soaring birds with large broad wings, such as the pelican, may have elements optimized to resist torsional rather than dorsoventral bending loads. These results are discussed in the context of the cross-sectional geometry of the forelimb elements.