Adolescent pigeon stuck in garden

Hello, 

I am not sure if this is the correct forum however it seemed the most appropriate. A young Pigeon has found its way into our garden, it doesn't to have seemed to master the art of flying yet, it is a decent size and almost fully feathered and an adult pigeon, presumably its mum has visted twice today to feed it. I am somewhat concerned as our street has a number of cats that come through the gardens and we have previously had a sparrow hawk take out a rather large wood pigeon in our garden, that the young thing will become food for someone. I have put some water down for it but they seem keen to stay away I know that the mother knows where it is and so moving it seems like it would cause more problems for the young thing, but I was wondering if there any other ways to safegaurd it and how long we can expect our garden visitor to be staying?