Perching BirdsPosted: November 12, 2014
Do you ever wonder how birds like these House Sparrows can sleep without losing their grasp on a branch or something else that must be gripped?
The feet of perching birds have a pair of tendons which are connected to the deep flexor muscles of the leg. When the bird lands and the ankle bends, both tendons automatically pull, clenching the toes closed. As long as the ankle is bent, the toes remain locked in place, giving the bird a sure grip even when sleeping.