The scientists found that Shinta as well as the other birds alternated periods of rapid head or eye movements, called saccades, with periods where their vision was fixed on a specific point. Such movements are based on environmental information, such as rustling trees and available light. The time between saccades changes as a bird detects a potential target, like a rabbit or pheasant.
Falconer Robert Musters designed the tiny camera-holding helmet worn by Shinta, and is the man seen from her viewpoint in the videos.
Amador Kane said that, in order for us to better understand the process, we imagine a hunting bird making a decision to change its direction of gaze based on the visual info streaming in as it visually scans its environment.
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"The longer it looks and finds no indication that prey is present, the less likely it will find prey initially and the more likely it is that looking in a different direction will be more profitable," she said. "However, if the predator gives up after a predictable time, the prey can use that regular timing in its own decisions about when to flee or break cover based on that information."
What actually happens then is "a compromise between these two factors, and is indeed similar to that found for human visual searches."
Graham Martin is a University of Birmingham professor and expert in raptor hunting behavior. He was not involved with the study.
"Experienced falconers know that after removing the hood from a bird that is ready to hunt, it will exhibit very characteristic head movements," Martin said. "The really experienced falconer can even read their bird and predict when it is about to take off in pursuit of prey just by watching these head movements. What cues is the falconer attending to?
"This work throws some very interesting light on this."
Photo: Shinta, a Northern Goshawk, wore a head-mounted camera to assist with a study on raptor hunting behavior. Credit: R. Musters Watch: Who Are The Eagle Hunters Of Mongolia?