Not that this anecdotal observation answers any questions raised above, but it sure changed my thoughts about where wolves will travel to get a meal.
I watched four wolves kill an antelope down in the Madison Valley, way out on the flats, two miles from any cover, in bright sunlight of a February afternoon. I had been seeing dead antelope carcasses and was writing it off to coyotes.
Given these ranches benefit from aerial control of coyotes, the number of coyotes is pretty low by the time I start wolf hunting in late January. What I watched that day might have been a better explanation for the antelope carcasses I was seeing.
I would have never guessed that wolves could catch an antelope out on a big flat, but watching it from a mile away, it looked like taking candy from babies. It went kind of like this.
One black wolf emerged from an irrigation ditch and started trotting toward a group of scattered and grazing antelope. Upon seeing his intention, this wintering group of 40+ antelope formed a tight herd and started running at a pretty good clip.
Anyone who knows the Madison has seen that almost every section has a fence around it. Seems the wolves have figured that out also, and how antelope will respond when they are chased by wolves.
Once the antelope herded up, they circled the square mile pasture a few times, with the wolf loping casually behind. I was smiling, thinking the antelope were just giving the wolf some exercise in the futility of chasing them in wide open spaces.
In the interim, three gray wolves emerged from the same spot in the irrigation canal and bedded down on a little knob in the middle of the pasture, watching intently. It almost looked like they had sent the black wolf out for "remedial training." Or, maybe the black one had drawn the short straw and it was his turn to catch dinner.
This game of chase when on for about five minutes. Then, as antelope often do, they tired of being confined and they lined out in a straight vector, the direction of which only the lead antelope can explain. That is what this herd did, with the black wolf following 200-300 yards behind.
When antelope hit a fence, they do not each find their own place to cross and all get across in a hurry. Nope, they bunch up and they all cross in the same spot, single file.
Seeing the herd was now bunched up at the fence, delayed by their habit of single file passage, the black wolf put on the burners. Within twenty seconds, he had closed the gap, dove into the back of the now bunched up herd, and with hardly any struggle, had an antelope by the throat and was dragging it off toward his mates.
Seeing their friend's success, the other three wolves rose from their beds and trotted over to enjoy the bounty of the day. Had I not seen it with my own eyes, I would have doubted it.
Maybe I am giving wolves too much credit, but this seems like a definite learned behavior where a very smart animal has learned how to use man-made landscape changes to their hunting advantage. And the antelope have yet to figure out a way to not fall into the trap. I suspect they know the antelope winter there and by mid-winter, they know it is easy to make antelope a big part of their winter diet.
Just a couple miles away are herds of winter-stressed bulls with big sharp antlers. I suspect wolves would rather invest the energy and take the lower health risk that comes with killing six antelope that have lost what little headgear they have, than to chance injury/death with 600 pounds of pissed off bull swinging swords from his head.
The ranch it took place on was one of the few where I did not have permission, or I could have easily snuck down the same irrigation ditch and had two hundred yard shots at four wolves feasting on a fresh killed antelope. I now have permission on that ranch and hope the scene repeats itself this winter. I would much enjoy taking advantage of a man-made structure, much the same as the wolves have figured out.
I now carry my video camera on all my trips. That segment would have been an amazing piece of footage, even if it were from a mile away.
I have no doubt that wolves can adapt to human presence far better than their prey. I doubt that event explains the question raised by the OP, but it is still one of the most remarkable wolf-prey interactions I have witnessed in my three winters of chasing wolves.
