In my youth I trapped beaver here in Oregon, along the Metolius River. While setting/checking traps I witnessed a doe being run down by three coyotes. They were on heavily crusted snow. The doe couldn't run on it because her hooves would break through the crust, while the coyotes could run on top of the crust. They quickly caught up to her and just started tearin' away at her hind end. Her screaming bleats were heart rendering.

I put her down with a single shot to the head from maybe 70 yards out. The coyotes scattered at the shot, but I figured they would come back later. Sure enough, the next day as I was again checking my traps, she was very "eaten up" and there were additional 'yote tracks around her.

I don't think coyotes are that efficient at keeping deer populations in check though, maybe some but not alot. Taking of fawns and the weak are much more likely than healthy adults.

Peace,