The snow angel of death

If you saw this in the snow, would you know what it was? Think a second before you read below.
Picture 2

Image: Gavin Murphy

A guest “blog” by Kyle Hill at Scientific American explains:

We have to assume it was a squirrel, but we know how it died. It died squirming and convulsing in the talons of an owl, locked in by the bone ratchets the owl shares with other raptors. Based on what was left behind, we also know that the attacker was likely a Great Horned Owl or a Northern Hawk Owl with a wingspan between 86 and 87 centimeters. All of this we can glean from a striking impression of a deadly strike.

There is perhaps no evidence of a kill more beautiful than these wing-prints left in the frigid Timiskaming, Ontario snow. Like throwing flour on the invisible man, the snow lets us see the tracks of an invisible predator—invisible at least to the squirrel.

With hearing good enough to sense rodents and other prey inches under the snow, owls feed by plunging their talons deeply through the drifts and into their prey. In the summer, the last thing many small mammals see is the owl. In the winter, strategies change, and many owls supplement their mammalian meat with that of small ground-dwelling birds like grouse. No matter the food, the killing itself isn’t pretty. Hawk owls in particular eviscerate small mammals before eating their heads and organs, thereafter caching the remains.

More often than not, nature is cruel, and hard on human sensibilities. But we can also subsume—or at least dull—those sensibilities by realizing natural selection, though it’s produced what looks to us like cruelty, has also given rise to both awesome animals involved in this interaction: the wary squirrel and the carnivorous owl.

16 Comments

  1. Posted January 30, 2013 at 6:24 am | Permalink

    the second one is clearly man-made: see the motion tracks of the arms going up and down! Footprint at the bottom, narrower midriff, two clearly recognizable legs. DOH!
    And if you read the full post you link to it becomes apparent that the paragraph you pasted above refers to the very image you show at the top, not the human made “snow angel”.

    • Posted January 30, 2013 at 6:48 am | Permalink

      After reading the relevant links, I agree.

    • whyevolutionistrue
      Posted January 30, 2013 at 7:00 am | Permalink

      Yes, I know that; the top image is genuine. In fact, I’ve removed the second picture and link as clearly fake. Thanks.

  2. gravelinspector-Aidan
    Posted January 30, 2013 at 8:06 am | Permalink

    Berlin called. They want their Archaeopteryx back!
    (Also testing to see if Gravatar has picked up my revised name?)

    • gravelinspector-Aidan
      Posted January 30, 2013 at 8:08 am | Permalink

      Yes, it has got the name, and per new roolz, anyone should be able to click on the name to get (some of) my details, and/or an email link (bit difficult for me to check that, being logged in already).

      • Notagod
        Posted January 30, 2013 at 9:02 am | Permalink

        No linky name there you rascally imposter. Now, I want my gravelinspector back!

        • gravelinspector-Aidan
          Posted January 31, 2013 at 11:23 am | Permalink

          Oh well, I was rather dubious of this “Gravatar” thing anyway. apart from providing a pretty picture (amphibolitite under XPL, as if you couldn’t guess), I don’t see that it provides much of value.

      • Notagod
        Posted January 30, 2013 at 8:48 pm | Permalink

        Decided to try clicking on the picture instead of the name and it does work similar to what you describe.

        • gravelinspector-Aidan
          Posted January 31, 2013 at 11:24 am | Permalink

          Oh well, now I know.

  3. Diane G.
    Posted January 30, 2013 at 12:10 pm | Permalink

    sub

  4. Davros
    Posted January 30, 2013 at 1:43 pm | Permalink

    Looks a bit like the famous archeopteryx fossil.

  5. Lars
    Posted January 30, 2013 at 3:07 pm | Permalink

    There doesn’t appear to be any sign of a trackway left by the prey, which makes me wonder if perhaps it wasn’t a squirrel, which would be expected to bound, or try to, through the snow from tree to tree – perhaps instead it was some habitually subnivean species (vole, weasel) which had come to the surface for a quick breather and got nabbed. Owl hearing is very good and this one may have heard the prey scrabbling about under the snow in time to be ready for any movement breaking the surface.
    One of my first environmental consulting jobs was on winter ecology in the Thousand Islands. We were baffled by prints something like these on our first few snowshoeing track surveys till we noticed the abundant associated droppings and realized that they were left by ruffed grouse lifting off from their overnight dens under the snow.

    • JohnnieCanuck
      Posted January 30, 2013 at 4:38 pm | Permalink

      Read the third paragraph quoted in the post above to understand that the owl doesn’t need to wait for the burrowing prey to break the surface.

      If it were a squirrel, it likely would have been bounding and its prints were lost in the impact. Wouldn’t surprise me if the owl caught it in mid-bound and drove it into the snow.

      • Lars
        Posted January 30, 2013 at 4:45 pm | Permalink

        Yes, but look at the scale – the squirrel must have been taking heroic bounds for the penultimate ones to be outside the frame of the photo, and given the apparent depth of the snow, it would have had difficulties in covering much ground per leap.

  6. Posted January 31, 2013 at 6:04 am | Permalink

    David Maas found another one, with a prey track: http://www.drip.de/?p=2527

    • Diane G.
      Posted January 31, 2013 at 1:36 pm | Permalink

      Thanks, that’s very cool!

      It’s interesting how these owls appear to pounce and then be able to lift their wings without at all moving them through the snow (which would smear the imprints of the individual feathers). I suppose that helps prevent picking up any snow load on the wings.


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