Linda and Peter reported earlier this morning that the Main St. pair were both nest building and feeding.

Bob reports from later in the day:

As of this morning, at least one of the young Dippers from bridge 3 has left the nest. Meanwhile I watched the blue banded male adding moss to the new nest.
The young at the Main st nest box are literally on the verge of fledging. I observed a fledgling out of the nest and on the edge of the nest box while the adults seemed to be more interested in building their second nest in the concrete hole on the downstream side.

fdl