Meeting Abstract

27.6  Saturday, Jan. 4 14:45  Not all asymmetric feathers are created equal; a survey of flight feathers reveals several morphological strategies for achieving vane asymmetry FEO, TJ*; PRUM, RO; Yale Univeristy; Yale University teresa.feo@yale.edu

Feathers come in a wide diversity of shapes and sizes which birds use to accomplish a variety of functions from sound production to fight. Each feather is a complex branched structure with an equally complex tubular development. Due to this complexity, there is generally more than one way to modify development and morphology to achieve a particular shape. The flight feathers of all extant flying birds are characterized by a strong asymmetry in vane width, which is known to have an aerodynamic function. Each feather vane is a composite series of branches called barbs, and barb angle and barb length determine the width of a feather vane. Previous research on a small number of flight feathers has found that either barb angle, barb length, or both can vary between the vanes of an asymmetric feather suggesting that a feather can employ one of several morphological strategies to achieve vane asymmetry. We surveyed wing and tail feathers across the extant avian clade to characterize the relative importance of each morphological character in generating asymmetry. We found that differences in barb length between the two vanes of a flight feather generally increase with increasing vane asymmetry, whereas differences in barb angle do not show the same trend. Instead, large differences in barb angle between vanes are found only in certain types of flight feathers, suggesting that the different morphological strategies for achieving vane asymmetry may be associated with different functions.