Laurie......While I have never watched Wrens fledge before I have watched many others. It is typical behavior for the parents to clear the way for them, however babies are babies and come (or go)when they are ready. Most of the babies should make it up to a tree branch then the parents will escort them higher up into the tree. Some babies may not have the wings going quite right on the first try and drop to the ground, the parents will encourage them and will usually have them up and flying in a few minutes. If a baby leaves the nest too early and can not fly, the parents will get it to a place of safety and continue feeding it untill it can, usually by the next day.