If there are two or more bunnies in a slight depression in the ground, it is a nest. Leave it alone. If the nest has been disturbed, please see https://wildlifewelfare.org/injured-wildlife/rabbits .
If you find a single bunny with its eyes closed on flat ground unprotected, – it may have been dragged from the nest by a cat, dog or bird. Carefully check the area for other bunnies. Put baby(s) in a box with towels or blankets, keep warm, and bring it to a licensed rehabilitator. Baby bunnies can jump surprisingly high. Keep a lid on the box at all times. Many times they jump out and are then injured.
If you find a bunny whose eyes are open and it hops around, then leave it alone. This bunny is probably ready to leave its nest. It should be about the size of a tennis ball or larger. If it doesn’t hop away from you, that does not necessarily indicate there is a problem. Bunnies have a “freeze” instinct. When danger approaches, the bunny freezes in place to keep from being detected. A rabbit that freezes like this is extremely frightened. Leave it alone.
Most of the bunnies brought to wildlife rehabbers should have been left in the nest. If you find a rabbit nest, you should leave the area alone. The young will not take long to leave the nest (about four weeks if they are found as newborns). If a family pet finds the nest, protect the area by restraining the pet or placing a wheelbarrow or other object over the nest site (remember to leave space where the mom can easily get in and out). It is important to keep children, cats, and dogs away for a couple of weeks.