This nest was below the bridge which had walkers and the building traffic going over - the young were in and out like fiddlers elbows - the parents darting down to feed them between trips by the dumper truck! I retreated down river later and watched the action thro binocs - they were just above the 12ft wall of the goyt and the river below and trying to teach themselves to fly ... my heart was in my mouth that one would drop into the water ....