Peregrine Thursday

August 26, 2010 • 5:33 am

Peregrines have several techniques for killing on the wing.  The first involves bashing into a bird with the feet clenched into “fists,” knocking it out of the air (and perhaps out in general).  The peregrine then retrieves the bird on the ground.   In the second, the classic “stoop” kill, it swoops down on its prey from above, grasping it with its terrible talons.  If the bird is small this can kill it immediately.  If it doesn’t the peregrine takes the bird to ground and finishes the kill, usually with a bite that breaks its neck.  Like all members of the falcon family, the peregrine has a special adaptation for breaking necks—the tomial tooth, a sharp projection on the upper beak that can sever spinal cords with a single nip:

A birdy colleague of mine pointed out that while a bite with the tomial tooth may paralyze the prey, it may not kill it, so that the prey could be plucked and eaten while still alive.

Finally, for large birds like ducks, there’s a danger of swooping in from above, since the large, flapping wings of the prey could cause an accident.  But the peregrine can take these birds from below, which means flying upside down at the moment it grabs the bird.  Large prey taken this way may not be killed in the air; they’re taken to ground and dispatched there.

Here’s a peregrine using the “bash” technique on a much larger red-tailed hawk (Buteo jamaicensis) that it sees as a threat to its young.  I’m not sure what happened after the hawk was bashed from the air; it may very well have died.

And here’s a peregrine coming back to its trainer at high speed.  The landing is a bit awkward!

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Near the brook a heron lay in frozen stubble.  Its wings were stuck to the ground by frost, and the mandibles of its bill were frozen together.  Its eyes were open and living, the rest of it was dead.  All was dead but the fear of man.  As I approached I could see its whole body craving into flight. But it could not fly.  I gave it peace, and saw the agonised sunlight of its eyes slowly heal with cloud.

No pain, no death, is more terrible to a wild creature than its fear of man. A red-throated diver, sodden and obscene with oil, able to move only its head, will push itself out from the sea-wall with its bill if you reach down to it as it floats like a log in the tide.  A poisoned crow, gaping and helplessly floundering in the grass, bright yellow foam bubbling from its throat, will dash itself up again and again on to the descending wall of air, if you try to catch it.  A rabbit, inflated and foul with myxomatosis, just a twitching pulse bleating in a bladder of bones and fur, will feel the vibration of your footstep and will look for you with bulging, sightless eyes.  Then it will drag itself away into a bush, trembling with fear.

We are the killers. We stink of death. We carry it with us.  It sticks to us like frost.  We cannot tear it away.

—J. A. Baker, The Peregrine

15 thoughts on “Peregrine Thursday

  1. “Are God and Nature then at strife,
    That Nature lends such evil dreams?
    So careful of the type she seems,
    So careless of the single life”… Tennyson

  2. I saw a peregrine take a pigeon – it hit it as the pair flew up a cliff. The pigeon seemed to be trying to find a small crevice to hide in: as it was about to reach one the hawk came from below and seemed to smash the pigeon into the crevice, landing there in a cloud of feathers. So close to safety! I also saw one take a duck from a flock on an estuary – again the cloud of feathers as it struck; I assume it used the ‘bash’ technique but it seemed to be from above, and it left the duck to plummet down out of the flock and hit the mud, before it came down to finish it off.

  3. The attack on the red-tail hawk reminded me of observing a peregrine nest in the Yorkshire Dales a few years ago. There were a number of jackdaw nests in the same cliff area, and I wondered why the jackdaws would nest around such a dangerous predator. The adult peregrines would even catch an occasion jackdaw after the chicks fledged, apparently just to show them how. It seemed crazy to nest around the falcon’s nest.

    I suppose the answer is that the presence of peregrines kept ravens and other nest predators away, which were an even bigger danger to the jackdaws and their young than the peregrines were. For the most part, the peregrines fed on pigeons and left the scrawny jackdaws alone.

        1. LOLs! Or is that LOwLs?

          “I can’t beer another day.”

          Btw, thanks for this series and the hunting technique details. Much appreciated!

  4. Why did birds lose teeth, which their ancestors had? Most birds seem to swallow food.. which is hardly efficient. I read that some birds actually swallow stones, into their ‘gizzards’ to help with grinding. But it just doesnt seem to be a better system than having teeth, even if those were primitive and primarily help in chopping food to pieces.

    1. For starts, the bill is not a modified jawbone in the sense that it’s not bone at all – it’s keratin, and (at least with parrots) continues to grow like fingernails, so it’s not like teeth were lost from a beak-like structure. It’s probably a matter of moving into different niches – teeth would be of little value to a bird capitalizing of food found in dead wood, like a woodpecker, for instance. And the regrowth aspect surely has numerous advantages over teeth with some diets.

      1. I would think a bill would be lighter than a jawbone and teeth doing a similar job, too. I don’t know much about bird evolution or how the bill came out, though.

    2. At a guess they had at one time both, in the same way that baleen whales had both in the beginning.

      And supposedly they both lost teeth later for the same reason, at the time the new arrangement was efficient enough without them.

      As for why, I note that a beak is useful for manipulation and probing, something an animal with forelimbs tied up for other functions may have had use for in some niches.

  5. I very much doubt that red-tail hawk was killed. It looked almost completely in control at the end of that short clip.

    As for beaks and teeth, I know there are mutant chicken embryos that begin to grow teeth from the beak, so it’s quite possible that beaks were well along before teeth went by the wayside.

    In any case, I don’t see swallowing stones as an inefficient replacement for chewing with teeth. Most carnivores with teeth don’t chew at all – they grip, rip, tear, and swallow. I don’t expect early birds were any different in that respect. The stones would be a later adaptation that helped with new vegetable diets.

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