Birds of a feather

“There’s no reason anyone else should out-climb you,” claimed an XC clinic instructor I was listening-in to. “Not even the vultures.” It’s ambitious advice, and few manage to hold their position in a climb with vultures for long. Connecting above raptors in the thermal they’ll eventually climb up past paragliders and on light days they float up while pilots float down.

Smaller birds like finches, use bounding flight – a few flaps followed by a freefall arc – to manoeuvre in and out of trees and bushes. Mid-sized birds flap consistently to stay airborne, but birds of prey rarely flap their wings. To find food they need to be able to stay airborne efficiently while they scout for the next meal. Over several thousand years they’ve evolved to be masters of gliding, so...