A Common Kingfisher perches on a twig in the breeze, keenly watching something of interest. The twig sways about. The bird’s body sways about. The bird’s head stays locked into its position in space. This is head or gaze stabilization, the ability to maintain steady visual contact while the body moves around.
…for birds, many of which zip through trees and divebomb prey at high speeds, gaze stabilization is indispensable, fascinatingly complex, and, for those watching, even a little amusing at times…
Thanks in part to a large number of vertebrae and muscles in their neck, birds can hold their head in place even when their body’s in motion. According to David Lentink, an assistant professor at Stanford University who studies biological flight, this adaptation helps birds stream high-resolution visuals when moving quickly through complex terrain. “They keep their head absolutely horizontal at all cost because that way they have the most reliable information, which they have to stream at high rates,” he says. “When you’re maneuvering like crazy . . . you need a perfect vision platform.”
h/t Katy Kiernan.