to catch a mouse

The best way to catch a mouse is to be a Great Gray Owl, with hearing out of this world to localize the mouse under a foot of snow, a dive bomb attack force that can break through a crust of snow hard enough to support the weight of a 180 pound man, sharp talons to grab the mouse scurrying along under all that snow, and a crushing beak that can separate the mouse brain from its spinal cord.

Behold! The mighty mouser! Notice those two parabolic reflectors of specially arranged feathers surrounding the eyes — that’s what captures the sounds of voles scurrying along their tunnels beneath the snow. Asymmetrically placed ears on the side of the owl’s skull receive sound at different times and help the owl localize exactly where the sound is coming from.

On a one-day trip to Sax-Zim bog, we were lucky to find a champion mouser Great Gray Owl hunting right next to the road along one of the boundaries of the bog. It caught and ate an amazing four mice in under an hour. In fact, it was 100% successful in its mousing attempts!

I’ve put together a series of images into a very short video, accompanied by special “hunting” music so you can enjoy what I was able to see and photograph. If you’re looking at this post in your email, you might need to go to the Backyard Biology website to view the video (click on the title of the post in your email to get to the site). The video is best viewed in full screen (rectangular icon in the lower right corner of the video as it plays), then hit ESC to return to the blog post.

In the video sequence you see the owl take off, from a perch, fly quickly to a site and dive to the snow feet first, dip its head down to the feet to grab the mouse in its beak, fluff its wings above the snow level to take off, fly to a perch, spend some time looking around (not shown in the video), take the vole’s head into its mouth and crush it, transfer the vole to its feet and squeeze it some, then back to the mouth where it is swallowed.

Great Gray Owls look around continuously as they try to localize sounds they hear coming from beneath the snow. In this image, the owl was perched about 10 feet above the snow and stared down intently for several moments before making a dive, and coming up with a mouse.

Our Great Gray caught four voles in a very short span of time. But on average they may catch and eat up to seven voles a day while hunting in the early morning and late dusk hours during the coldest winter days.

13 thoughts on “to catch a mouse

    • Hi Jim, make sure you get a map and check with the folks at the Welcome Center about where birds have been seen. The GGO individual in this post was on MN 7 (boundary road) south of Arcola Rd intersection. Just look for people parked on the east side of the road (facing north) and that’s where the owls will be.

  1. Really enjoy the video sequence. How amazing you got to observe this! Is it unusual for them to be diurnal hunters?

    The black-billed magpies in my neighborhood have come up with a more effective way to “catch” mice. Eilene puts out snap traps baited with peanut butter and tosses the unlucky rodents into the yard!

    • No, the Great Grays typically concentrate their hunting time in the early morning and at dusk. But this owl was quite active up until about 10 a.m. It caught the mice in rapid succession with just a few minutes between captures, so it was hungry I’m guessing.

      Funny you mention the snap traps for mice, we always get a bunch of house mice invading the basement shop and storage area in the fall, just when cold weather sets in. We have never figured out where they get in, but it’s a regular occurrence at that time of the fall. So my husband traps all of them, I put them out where the bird bath used to sit in the summer, and some fortunate wildlife carry them away. We have nesting Great Horned Owls in the backyard so maybe it’s them. Or it could be the red fox?

  2. I always thought all birds picked apart their prey! The photos are fantastic! I am in awe of their ability to hear movement under the snow. Makes me wonder if the rest of their world is so loud we wouldn’t be able to stand it – or can the hearing be focused?

    • Thanks for asking about the owl hearing, Sandy. The pattern of their facial feathers is critical to their hearing. The feathers are shaped like two parabolas, and they collect what we would call infra-sounds and transmit it to their ears which are slightly offset from each other on the side of the owl’s head. The way the owl pinpoints the location of the sound is by the difference in the time of arrival of sound at the two ears.

      Raptors (hawks, owls, eagles) will gulp smaller prey items down whole (and head first), unless it’s something big like a grouse or a rabbit, and then, yes, they pick them apart using that sharp tip of the beak.

  3. “The way the owl pinpoints the location of the sound is by the difference in the time of arrival of sound at the two ears.” Mind somewhat blown…somewhat only because I get it, but it’s an innate sense for them, at least I’m guessing innate rather than learned?

    • Yes, innate in the same way that you know to turn your head to orient yourself to where a sound comes from. For example, in a noisy room of musicians practicing a song, you might turn your head to identify the one musician that was off key or badly tuned by pointing one ear directly toward the noise, and one directly opposite — that maneuver maximizes the difference between sound intensity at your two ears and your brain then interprets the sound direction from that difference. Unlike us, Owls have asymmetrical ears, shaped differently and placed differently on each side of their head. The ear asymmetry is what produces the difference in sound intensity information for the owl brain to interpret.

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