When coyotes first started showing up here the deer hunters were worried about the potential predation on the deer herd. Our game managers released an article that said coyotes eat a large variety of foods and deer almost didn't factor in to their diet. The big question was, if this was true, how come every scat pile from a coyote that you ever see here is made up of mostly deer hair. The earlier story has since been changed but it took 30 years....
Interesting, around here I've rarely seen deer hair in yote scat. But when we get around to seeing too many or ones close to teh house we shoot a few.
But my fawn survival here at the house has been close to 100%, at least whats generally lost is by vehicles typically. Loose one maybe every few years to unknown... IE not on the highway and just goes away...
I suspect that various regions will have similar results also. IE they will eat what they have to, to survive.
From what I read on wolves, tehy are a bit more efficient to say the least.