Feather Parts Reattach

close up of green and blue bird feather plummage

Biological Strategy

Birds

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Attach Temporarily

Living systems must sometimes, temporarily, stay in one place, climb or otherwise move around, or hold things together. This entails attaching temporarily with the ability to release, which minimizes energy and material use. Some living systems repeatedly attach, detach, and reattach for an extended time, such as over their lifetimes. Despite being temporary, these attachments must withstand physical and other forces until they have achieved their purpose. Therefore, living systems have adapted attachment mechanisms optimized for the amount of time or number of times they must be used. An example is the gecko, which climbs walls by attaching its toes for less than a second. Other examples include insects that attach their eggs to a leaf until they hatch, and insects whose wings temporarily attach during flight but separate after landing.

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Birds

Class Aves (“bird”): Eagles, hawks, sparrows, parrots

Birds are evolutionary engineering marvels. They are descended from dinosaurs, but are far from our idea of heavy, scaly reptiles. Of the specific adaptions that set them apart, most notable is flight—although some mammals can fly, birds take the prize for abundance in the skies. Many birds have hollow, lightweight skeletons and specially-designed wings to help them stay aloft. They also have feathers made of keratin that help them stay warm, attract mates, and improve navigation and aerodynamics in flight. In contrast to their dinosaur ancestors, they lack true teeth and have replaced them with specialized beaks and bills.

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Feather filaments of birds connect to each other with interlocking hooks.

“A central shaft carries on either side a hundred or so filaments; each filament is similarly fringed with about a hundred smaller filaments or barbules. In downy feathers, this structure produces a soft, air-trapping fluffiness and, therefore, superb insulation. Flight feathers have an additional feature. Their barbules overlap those of neighbouring filaments and hook them onto one another so that they are united into a continuous vane. There are several hundred such hooks on a single barbule, a million or so in a single feather; and a bird the size of a swan has about twenty-five thousand feathers.” (Attenborough 1979:173)

“Disarranged feathers are carefully repositioned. Those that have become bedraggled or have broken vanes are renovated by careful combing with the beak. As the filaments pass through the mandibles and are pressed together, the hooks on the barbules reengage like teeth of a zip-fastener to make a smooth and continuous surface again.” (Attenborough 1979:179)

Last Updated September 17, 2018

References

Book

Life on Earth: A Natural History

Boston (MA): Little, Brown and Company 319 p. | 01/10/1981 | Attenborough D

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