The chimney swifts cannot perch as they do not have the opposing talon - birds' versions of thumbs. They cling to things and are great at climbing up and down on vertical surfaces.
This year, the babies have been tumbling from their nest to the hearth below. When they are as old and fat as this one (I was told after I took it to the Wildlife Care Center), you can reach up into the chimney provided there is no flu or you can reach past the flu and set the baby on the wall and it will either creep back up to it's nest or the mother will come down to the baby to feed it. I decided to leave it with its 3 other siblings I had taken to the care center each of the three days before this one fell from its nest. This little one has a little bit of food on its beak as it was just fed emergency food to keep it from getting dehydrated (soppy dry dog food made into a pudding is one recommended formula) before I took it to the Wildlife Care Center. Today, the care center told me it has survived as did all of its siblings I had rescued, but one, who had also come down the chimney. Hopefully, it is the last one to fall. When these babies are ready to fly (perhaps in a week), they will be brought back, nearby my house, where they were born to be released.
After the nest or nests are empty and the birds have flown south, we must put a screen across the chimney once again. It is too worrying to have the little ones tumble down the chimney. Even the dog gets upset as he has been trained to not chase birds and when the little ones are cheeping and flapping about, he gets up and goes into another room.