Comment by mrec
9 hours ago
> Over the next few days, the owl makes 16 more strikes at mice, missing only four times, each time by less than two inches.
How did the experimenter measure miss distance in pitch darkness? IR illumination is presumably out in case the owl was able to see it, and I didn't think thermal imaging was a thing yet in the late '50s.
Scratch markings on wax flooring beneath the leaf cover or the grid location on the floor was instrumented to report to telemetry when carrying weight of the owl. Assuming the mouse had its ankle rope tied to a pin nailed into the floor.
He did use a IR stroboscope and a camera, as owls can apparently not see IR.
But in that case this bit of TFA feels a bit out of place:
> To eliminate the possibility that the owl was [...] detecting heat from the body of the mouse (for instance, by sensing infrared light emitted by a warm body), the experiment is repeated with a mouse-sized wad of paper dragged through the leaves
It doesn't seem like owls have infrared vision, in that case an IR camera looks like the easiest way to go.
Completely random guess, but perhaps ultrasonically? Ultrasonic rangefinders are relatively cheap and accurate these days, so maybe they were too in the '50s?