Baby birds need moving! What should I do?!?

I found a nest of baby birds under the metal lid of our propane tank about a week ago. The propane guy is coming tomorrow to refill the tank and I don't know where to put the birds in the mean time. The propane tank is sitting on a concrete foundation so I was thinking about just putting the nest under the tank until the guy is done. Any advise???? I don't want to harm the birds or have the mother desert them. Thanks =)