Human intervention is seldom the best option for wild bunnies. There is a 90% mortality rate with orphaned baby rabbits in human care, especially cottontails. This number increases if the rabbits are very young and their eyes still closed. They are extremely difficult to "save". There is little substitute for the nutrients their mother's milk provides. Often they die of bloat, improper feeding or overfeeding. The immune system of an unweaned bunny under 4 weeks is not fully developed. Although they are very cute, wild baby rabbits are very easily stressed & just handling it can cause them to have heart failure.
Importantly, by 10 days of age when their eyes open, the babies will begin eating their moms cecotropes (night feces) directly from the mom as they are produced. The night feces is different than what is produced during the day and provides vital nutrients to the baby that we cannot supplement.
The best thing you can do is put the bunny back where you found him unless you know there is a predator in the area, the bunny has obvious injuries or you have found the mother rabbit dead. The fur lined nest is shallow & just below the surface of the grass. The babies in the nest will be covered with grass and rabbit fur. Mother rabbits only come back to the nest once or twice a day between dusk and dawn. If things are going as should be, you may never see the mother rabbit.
Baby rabbits are born without fur but have a coat within a week and their eyes open around 10 days old. The bunnies are usually ready to be on their own by 3-4 weeks of age.
Scenarios that indicate intervention is necessary:
You found the mother dead:
Do not handle them any more than to prepare for transport.
SEE TRANSPORT INSTRUCTIONS BELOW.
You discover that a cat caught a baby bunny and has caused injuries that break the skin.
Get it to a wildlife vet or rehabber IMMEDIATELY. Cats carry a very lethal bacteria in their saliva which can easily be fatal for a rabbit in 48 hours.
SEE TRANSPORT INSTRUCTIONS BELOW.
Your dog has discovered the nest of babies in your yard!
Replace any babies that have been drug out of the nest. There are several ways to protect the bunnies from your dog's insistent curiosity. Most obviously don’t let your dog in the area of the babies if at all possible. That might mean having to keep your dog leashed when out in that area until the babies leave the nest at around 3 - 4 weeks.
Another idea is to place some sort of protective “guard” around the nest during the day remembering to uncover it by dusk when the mother will return to care for her babies. A curved garbage can lid works well with some sort of weight on top so the dog can’t move it.A bottomless crate works well, staked into the ground. Keep the door closed during the daylight hours propping the door open from dusk to dawn.
PREPARING TO TRANSPORT: THEY WILL DIE OF STRESS IF HANDLED INCORRECTLY
1. With clean hands or clean gloves place it/them in a very small box with bedding from their nest if possible or a clean soft towel.
2. Keep the box in a warm, quiet place away from children, pets, noise or bright lights.
3. If you have a heating pad, TURN IT ON LOW and place it under only 1/2 of the box allowing the baby to move if it gets too warm. (Please see additional directions on warming the animal here.)
4. If the situation forces you to keep it overnight- NO MORE THAN 24 HOURS- you can try to rehydrate with drops of WARM DISTILLED WATER from a syringe and only once the bunny has warmed up.
PLEASE NOTE: Rehydrating solutions like Gatorade or Pedialyte as well as water filtration systems kills the fatty acids that bunnies need to digest their food properly. If he will not swallow, do not force him as this can lead to aspiration.
If the bunny`s eyes & ears are not yet open, it may help to stimulate it to urinate/defecate by gently stroking the genital area with a dampened cotton ball in warm water.
DO NOT ATTEMPT TO FEED ANY TYPE OF FORMULA OR COW’S MILK.