The black-capped chickadees, on the other hand, are right on schedule- I think there are five nestlings now, which is about typical for their first clutch. Based on the nestlings' plumage (similar to adults now) and their tiny voices (starting to sound like chickadees), they are pretty close to fledging.
In our yard chickadees will often have two clutches, not common in chickadees, but not really rare. The neat thing is that the young from the first clutch will often help with the second clutch. Since it has been a cool spring and various things are delayed (flowering, fruiting, bird arrivals, etc...), it will be interesting to see if they have a second clutch.