For the first time in 15 years of living at my current house (Richmond, VA area) I have a nest of Chimney swifts in my chimney and love having them there. It started with what sounded like just one bird and I didn't know much about the species. Then I knew it was a nesting pair when the chicks hatched and the mass twittering and flapping started. This has been going on for weeks. From what I've learned this is about the time they should be leaving the nest and migrating. My questions and concerns - I still hear some twittering, but not near the volume or consistency, nor do I hear all the flapping anymore. Do some babies leave sooner than others and perhaps there's just one baby left that an adult is tending to? Would this still be an adult I hear after all the babies are gone? Do the babies fly and eat around my house and then come back into my chimney to rest or once they fledge are they gone for good? I don't think I've ever seen the birds on the wing, I just hear them at all hours of the day when they are in the chimney. I assumed it would just be one day and I wouldn't hear them at all anymore, not this tapering off type noise. I'm concerned something has gone wrong with the nest/babies since I don't know their fledging behavior. We do have a red tailed hawk that lives around our house, are they a threat to the babies? Should I attempt to look up the chimney? I don't want to disturb them. Thank you in advance for educating me on they typical 'what to expect' when you have a nest of swifts in your chimney!