Wedge-Tailed Eagle

Photograph by Jason Edwards, National Geographic

The feathers of a wedge-tailed eagle (Aquila audax) form a gauzy screen in Alice Springs Desert Park in Australia's Northern Territory. From a central feather vane sprout hundreds of filaments called barbs. The barbs in turn sprout other, smaller filaments, some with grooves and some with hooks that clasp the barbs together like Velcro, allowing the bird to fly.