I guess that you may know the story of the Ugly Duckling who grew up to be the most beautiful Swan. The young birds, called juveniles, often look very different to their parents. They have a lot of growing to do - they have to put of weight, grow feathers and be able to look after themselves eventually. Here are some photos of juveniles - can you guess the species from the list of names?
Ducks and wader chicks are very brave very early in their life. They leave the nest as soon as they can after hatching. This means that they are moving away from predators. Our Garden birds, like Robin and Blackbird, stay in their well hidden nest until they are nearly as big as their parents and can flap and fly (It's more like falling with style!)
Can you think of other birds, mammals, fish, reptiles or amphibians where the juveniles don't look like their parents?