The first clue was a magpie, flying low over the snow and sage covered hillside on our left.

Well, actually, the first clue was these two, perched on a tree just down the river.

But I completely missed that one. Even though the heeler sisters and I had a fun walk down to the river's edge, getting closer to these two raptors, without looking like we were getting closer. Didn't turn back until they started craning their necks to keep track of the strangely coloured canids below.

And apparently made some sort of farewell noise, as both heelers simultaneously stopped in their tracks and cocked their heads back towards the eagles' tree, listening to something I could not hear.

But I missed that clue. Wasn't until I saw the magpie flying low that my senses went on alert.

Somethin' dead around here...

And it was just around the bend, not 50 meters off the road. Buried under a black and white swarm of magpies and crows.

A deer. A dead deer. Or rather, what was left of her. Which wasn't much. The skeleton, with one foreleg and the neck and head attached.

So now the question. Why did she die?

She was fresh, on top of the new snow. Storm hit Sunday night, and now it's Tuesday afternoon. What's left of her carcass is on top of the snow, as is the blackening pile of her intestines, just a few meters away in the sage, and the still greenish pile of her rumen, ripped from her body a meters even further south. I would like to think she was already dead when that happened, but I know for a fact that isn't always the case. Nothing slows a running deer better than slashing its belly open so the stomachs fall out.

Seen it done by coyotes.

So, we know roughly when she died. The next question is, who?

The snow around the body is heavily trampled. Tracks of just about every predator and scavenger around, which is no surprise. I step uphill from the carcass and start circling, cutting tracks. Between the dead deer and the mountain, I find coyote tracks, headed down through a shallow draw towards the carcass. They used the cover of the draw to get closer without being seen. Following the multiple tracks up to the head of the draw, I find there are six sets of tracks. Two groups of three, headed downhill. Possibly six separate coyotes, but I suspect instead that it was three coyotes, coming down at least two different times to fill their bellies.

But all the coyote tracks are clear and neatly defined. On top of all of the snow. But closer to the deer, heading away from the deer up the same shallow draw, I find one single set of tracks.

And these are not clear. They are partly filled with snow. These were made while the snow was still falling. Much earlier than the tracks of the scavenging coyotes.

And they're big. That's not a penny in that footprint above.

That's my Sacajawea dollar from the gift shop at Lake, in Yellowstone. These tracks are considerably larger than the coyote tracks. About three to three and a half inches across.

Lion.

Which is a surprise, since we're next to a maintained road, in a popular recreation area (although only one vehicle had been there since the snow), and almost a mile from any sort of ridge or hill that could be considered natural cover for a mountain lion.

But here the tracks are. How did a lion manage to kill a mule deer doe out here in the middle of open sage?

I check the carcass again. Her teeth say she was about four or five years old. In her prime.

I dent the wood handle of my knike trying to break open her exposed femur, and resort to sawing through the bone with my leatherman. If the doe was weak and starving, her marrow will be red and fatless. But it isn't.

I would classify her marrow as "pink, semi-waxy". Which means her body had started to consume the marrow fat, hence the pink colour from the increased capillaries, but there was still some fat left.

She wasn't starving.

But on reflection, the tracks actually answer my question for me. The lion left its kill while snow was still falling. Yet the deer died on top of fresh snow.

She was stalked and killed in the middle of the blizzard that struck Sunday, probably Sunday night. The moon was nearly full, she and the other deer were probably up and active.

Only one thing left to do. Here I am, with a nicely refrigerated fresh deer carcass, neck intact, along the river. The CWD cases nearest to this country have been along the same river, about 25 miles north, and 50 miles south. The way deer move along the river valley, when that disease shows up in my country, I expect to be along the river.

So, it's back down to the truck, dig out the kit and surgical tools, and don the freezing cold blue gloves. (This confirms it for me... it's not even 20 degrees out there, yet my hands were fine until I put on the latex gloves. Latex must conduct heat.) And I extract the intact retropharyngeal lymph nodes.

And after cleaning the scalpel handle and tongs, which takes longer than extracting the glands, the heelers and I are on the road again.

Case closed.