(ORDO NEWS) — In winter, owl victims often hide under a thick layer of snow, and the birds have to extremely accurately determine the position of mice and voles before attacking. Now scientists understand how they do it.
The Great Owl is a large owl with a 1.5-meter wingspan that requires at least 500 small rodents a year.
Silently hovering above the ground, the tawny owl swiftly overtakes its victims and strikes them with a precise blow of its clawed paws.
However, if there are usually no problems with hunting in summer, then what to do in winter, when a thick layer of snow covers the ground in the forest?
Most mice and voles hide under it from predators, and the tawny owl flying above them cannot see rodents in any way, but still somehow manages to find lunch under the snowdrifts.
To find out how they do it, biologists from the University of California at Riverside (USA) conducted experiments in the snowy Canadian forests inhabited by tawny owls.
The scientists buried loudspeakers next to holes left by hunting owls, and then, using an acoustic camera, they checked whether it was possible to capture the low-frequency noise emitted by a chewing or burrowing rodent from different depths.
It turned out that under a half-meter layer of snow, the camera captures only the lowest-frequency sounds up to three kilohertz; all high-frequency sounds, such as the squeaking of a vole, were completely absorbed by the snowdrift.
This is probably why the tawny owl has such a large facial disk , up to 11 centimeters in diameter: it serves as a “radar dish” for them, helping to pick up even the quietest noises.
Soft wing feathers also contribute, which dampen the sounds of flight and allow you to focus solely on hunting.
In addition, scientists have found that snow distorts the source of the sound, creating an “acoustic mirage”: while the vole is in one place, the sound seems to come from another.
To destroy this illusion, before the attack, the owl briefly hangs in the air, finally correcting the position of the prey, after which it falls on it like a stone from heaven.
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