Quattro, the studies done in Maine still hold true today in Eastern states.
jake and others are experiencing Coyote expansion and seeing less Red Fox. This happened in my area 30 years ago, but really seen the effect 20 years ago when Coyote took a foothold.
It's nothing new. Maybe new to you and your area. But the Coyote continues to expand throughout eastern United States. Coyotes have a foothold in Georgia, Alabama, Mississippi & Louisiana, but friends say it's just like Pa. Still expanding in those states.
From my observations in my area, Where Coyotes have a foothold, Reds may be near towns, malls & industrial parks. I have a few examples where I only catch/trap Red Fox and never caught a Coyote. Very few, very rare around here.
On the other hand...
I have experienced trapping a few Coyotes off a property, only to have Reds move in within a month or so.
I have trapped several Coyote/Red Fox doubles. By that, two traps set within 10' from one another. Coyote in one trap, Red Fox in another.
Four years ago I was calling and killed a Coyote/Red Fox triple. Coyote, then Red, then another Red.
I don't know what I'm getting at. Not trying to say Reds-Coyote co-exist, the don't. But sorta like Coyote-Wolf relationship. If there is a edge or crack a Red Fox can set up on fringe of Coyote range, Red will do that.