Meeting Abstract

39.4  Friday, Jan. 4  The Pterylosis of the House Sparrow (Passer domesticus): An in situ study FULLER, J.M.**; HOMBERGER, D.G.; Louisiana State Univ., Baton Rouge; Louisiana State Univ., Baton Rouge jlamb2@lsu.edu

The pterylosis of the House Sparrow (Passer domesticus) was studied in situ based on the premises that (1) powered flight originated in small arboreal, lizard-like ancestors; (2) small, forest-living, hopping, and flap-bounding birds are the most likely modern birds to have retained a primitive flight mode; (3) the position, shape, and size of body feathers are instrumental in creating the aerodynamically streamlined body contours of birds; and (4) contour feathers can act as temporary turbulators to maintain laminar airflow during flight and, especially, landing maneuvers. The study is intended to test the hypothesis that the placement and properties of body feathers are correlated with specific aerodynamic demands. Hence, the type, location, and orientation of every feather on the body was mapped on digital photographs of specimens. Contour feathers are arranged in diagonal or chevron-shaped rows within pterylae that are supported by subepidermal fat pads, whose thickness correlate with the size of the contour feathers. Apteria are devoid of fat pads. The pteryla on the ventral side of the neck is asymmetrical in feather density and orientation, reflecting the asymmetrical arrangements of the cervical organs. Down feathers are concentrated in depressions on the body surface to enhance the fusiform body contours. They are particularly abundant throughout the cervical apteria and are noticeably sparse under the wings. Filoplumes are usually located on the medial side of contour feathers, but are also found next to some down feathers and in apteria.