Not every young bird, that has supposedly fallen out of the nest, needs help. Most of the time, a so-called 'branchling' doesn't need any help. This is the name given to a young bird that is still unable to fly, but is already exploring the area outside the nest in the nearby branches and bushes. The parents of a 'branchling' are always almost nearby and are concerned about their offspring.
When should you help?
You should only take a young bird home if you are sure that it is a real emergency - for example a really freshly hatched or a few days old young bird. A rescue is necessary if the bird is visibly injured or if you could see yourself that the parent bird has had an accident. Even if the animal is in an obviously dangerous place, you should also intervene.