image: This is a hook barbule with hooklets in the middle. view more
Credit: PNAS
A study explores how birds rearrange feathers after flights through gusts and foliage. The durability of bird feathers is evident in the ease with which birds preen and repair ruffled feathers using their bills after long flights in turbulent weather and through dense canopies. Through manipulation and X-ray microscopic analysis of the 3D structure of goshawk feathers, Shutao Wang and colleagues found that a cascaded slide-lock system prevents large external forces from tearing feathers. Feather vanes contain primary, secondary, and tertiary branches called barbs, barbules, and hooklets, respectively. When feathers are subjected to large external forces, hooklets slide back and forth along the curved margins of barbules, similar to a slide rail, and fasten to spines, which are buffer stop-like structures found at the ends of the barbules. The flexibility of the barbules under force ensures that an unzipping action separates interlocking structures on adjacent barbs without inducing damage; the separated barbs can be snapped back into place simply by stroking. Thus, the authors suggest, the cascaded slide-lock system allows birds to weather strong winds and repeatedly rearrange feathers--even after 1,000 cycles of barb separation and repair--without damaging them. According to the authors, the cascaded slide-lock model of bird feather repair could inspire the design of smart textiles and flexible devices.
Article #18-08293: "Repairable cascaded slide-lock system endows bird feathers with tear-resistance and superdurability," by Feilong Zhang, Lei Jiang, and Shutao Wang
MEDIA CONTACT: Shutao Wang, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, CHINA; email: stwang@mail.ipc.ac.cn
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