Baby animals trigger exactly the response evolution would predict: they look small, vulnerable and in need of protection. In the wild, however, being alone is not the same as being abandoned. Many parents deliberately leave young animals hidden while they feed, and young birds often leave the nest before they can fly well.
Do not turn a normal wildlife strategy into an emergency
U.S. Fish & Wildlife Service guidance says the best response in most cases is to keep your distance and leave the young animal alone. Deer, rabbits and many other species can leave offspring unattended for long periods while the parent feeds. Adults may also stay away while people are standing nearby.
A fledgling on the ground is often exactly where it is supposed to be
A mostly feathered young bird that can hop or flutter is likely a fledgling. FWS notes that parents are usually nearby and continue caring for it. A very young nestling with little feathering may be returned to a nearby nest when that can be done safely.
Hiding alone can be a survival strategy
Fawns stay still and rely on camouflage while the mother feeds elsewhere. Rabbit mothers also spend relatively little visible time at the nest. Constant parental attendance would advertise the location to predators.
Injury changes the decision
Visible trauma
Bleeding, an obvious broken limb, severe weakness or a major wound are reasons to contact a wildlife professional.
Known parent death
If you are certain the parent has died, expert advice is appropriate.
Pet attack
An animal that has been in a cat or dog’s mouth may have injuries that are not obvious.
Immediate danger
For some young animals, moving them only a very short distance out of direct danger may be appropriate—but call local experts when unsure.
Do not improvise food, water or a home
FWS advises against feeding injured or apparently orphaned wildlife before receiving expert guidance. Young wild animals have specialized diets and handling needs, and habituation to humans can reduce the chance that they can eventually be released.
Sometimes the kindest rescue is giving the parent room to come back
Watch from a distance, keep pets and children away, and call a licensed wildlife rehabilitator when there are real signs of injury or orphaning. Cute does not automatically mean helpless.