One word....Anything.
Coyotes will eat just about anything they can find, period. If there's a pasture nearby they will eat poop, yes cow poop, horse poop, or any other kind of poop. They will eat any fruit that drops at certain times of the year, persimmons is a delicacy, apples, pears, wild plums, ect. They will eat it. Roots, grubs, worms, insects, certain plants and grasses......it's all on the menu.
They will eat road kill, possums, skunks, cats, birds, snakes, turtles, ect., ect., ect.
I've even seen them walk the river bank looking for frogs, snakes, crawfish, minnows, turtles, or whatever else they could find.
That's how they manage to survive and thrive, they will eat absolutely anything they have to in order to survive.
Mice are actually a well balanced meal, rabbits are a delicacy when the can get them, and a deer or turkey is a full blown feast.
Kinda like cake and ice cream is to us.