The Unfeathered Bird
500 years after Leonardo, the mechanics of bird flight still enthralls.
- By Katrina van Grouw
- Illustrations by Katrina van Grouw
- AirSpaceMag.com, August 02, 2013
Katrina van Grouw is a former curator of the ornithological collections at London’s Natural History Museum, and a graduate of the Royal College of Art. In her new book, The Unfeathered Bird (Princeton University Press, 2013), 385 exquisite drawings and straightforward prose offer insight into what goes on beneath the feathered surface. Van Grouw will be signing copies of her book at the Smithsonian Museum of Natural History on November 19, 2013.
Although they are powerful fliers in pursuit of prey, most raptors (Eurasian Buzzard, above) are not capable of long periods of sustained flight; they need to conserve their energy for the chase. So the majority of groups rely on a passive approach to hunting: gazing out from a perch, hovering motionless in the wind, or using rising updrafts of warm air to keep them aloft while they look around them in search of food. Soaring birds have long, broad wings to provide an ample surface area to generate lift, and their deeply notched primary feathers create turbulence around the wingtips, which prevents stalling at low speeds. The ability to soar comes at a price, however. The Old World vultures went down the soaring route and lost much of their aerial maneuverability altogether.