Morphological basis for the waterproof characteristic of bird plumage

摘要

A surface variable, density of water-feather touching points (D_p) was proposed in this paper to express surface property of water repellency of contour feather. Tests in 29 species using breast contour feathers indicated that D_p was small in tericolous species, medium in wading and diving species, large in swimming species, with only a few exceptions. This implied that birds achieve appropriate D_p by optimizing the microstructure of feather to meet the requirement of water repellency. Therefore, D_p was a morphological marker linking structure and function of feather in studies of adaptive evolution of birds.