Corvids on Carcass II

Continuing the story of the elk, found dead in our arena, killed by wolves …

Taken with motion-sensor camera

Taken with motion-sensor camera

The carcass lay at the same place where last year’s carcass had been. And again, the crowd of ravens came, descending to feed on the second day. This is the pattern of the big corvids, documented by Bernd Heinrich in Ravens in Winter, studied by researchers in Austria[1]. Non-territorial ravens known as vagrants, find a carcass and shout out their find: “Haa!! Haa!!” The yell brings in more vagrants, a horde of birds that can dominate the carcass. Although it seems odd that a raven would announce the bounty, rather than keeping the find to itself, there is a good reason for advertising. By gathering the group, the non-territorials can control the carcass, fending off the dominant territorial ravens. Numbers allow vagrants access to the carcass, meaning they get at least some meat and offal; solo, they wouldn’t get any – making it worth shouting out the news.

The day after we dragged the carcass out of the arena, not one raven touched the dead elk, though I watched two of them flying overhead. A large raven stood in the ranch road most of the day. Ravens knew the carcass lay in the snow, ripped open by wolves, easy eating, easy energy. But not until the next day did the birds actually arrive to tear at the mound of meat and bone – fifteen to twenty of them all at once. It seems the vagrants sent out their call, and the masses came. Not until there was safety and dominance in numbers did the ravens land.

I watched the carcass as I did last year, walking down to the site, taking notes under the dead lodgepole pine that I called the Writing Tree, observing the disintegration of a graceful elk into a mangled mass of hide and bone, grace still present in a different form, the flow of dead creature back into life. This year, we also set up a remote, motion-sensor camera on the carcass to record what happened. On my visits, I pulled out one memory card, replacing it with the next, the camera capturing the events of the past 24 hours, showing just who had come to dine.

The wolves did not touch the carcass. The camera recorded them lurking in the background at night, and caught one young-looking wolf a few feet from the carcass in the day. But the big canines did not touch the dead elk until weeks later, when temperatures were too low to put out the camera, the canines’ presence shown by tracks, not photos. Did the wolves avoid the carcass because of the human scent? The presence of the camera?

Neither of those kept fox, coyote, or pine marten away, all of whom dined regularly at night. They seemed to take turns eating, fox for a time, then coyote, the pine marten dashing in for a quick bite. Coyote did come during the day, but never the fox or pine marten.

Raven checking out the motion-sensor camera

Raven checking out the motion-sensor camera (ignore date — wasn’t set after batteries changed)

Birds dominated in the daytime, including two mature and two juvenile bald eagles. Mostly though, it was the ravens. The camera shows the mass of black corvids clustered on the rapidly diminishing carcass, sometimes an eagle mixed in with the group. The ravens knew the camera was there: close-up pictures of raven eyes and raven heads document the birds’ investigation of the weird object strapped to a nearby tree.

Carcass. Scavengers. Ravens. So much like last year, but so much different. Yes, a different experience altogether.

Last year, the ravens came to know me. They would linger in the trees when I arrived, fly so closely overhead that I could see their taloned toes. Occasionally I had a back and forth verbal conversation with a bird or two. There was something mysteriously magical about my interaction with the ravens, like a boundary had been crossed.

This year, the ravens would see me approach and simply disappear. I watched the birds fly from the carcass site from a hundred yards away. By the time I was at the carcass, they would be gone, not one bird in sight, not a crawck or a call.

I tried to figure why? Why did the ravens shun me this year, connect with me last year? What was the difference? Was I not as regular in my visits? No, I was there regularly until I left for a week over Thanksgiving. There was a larger group of ravens this year, meaning more and at least some different birds than last year. Maybe that somehow resulted in the birds having no interest in me, the observer. Hmmm.

The motion-sensor camera? The camera. Looking back, I note the caption of my December 2014 blog: “The ravens leave the carcass when they know I’m there — especially if I have a camera.” Ravens are sensitive to cameras. Many times I’ve watched them pick up and leave when I take a camera out. No camera, and they stay around. So maybe it was the camera.

Or maybe there was truly something mysteriously magical about last year, that because of some intangible somethings that I do not know and cannot define, some boundary was crossed. An experience beyond the norm.

[1] Szipl, Georgine, et al. “With whom to dine? Ravens’ responses to food-associated calls depend on individual characteristics of the caller.” Animal Behaviour 99.0 (2015): 33-42.

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