I scanned around until I located one of the young osprey sitting on the line of a ship docked at the port.
It cried a bit then flew off in the direction of the fishing grounds just over a small rise where the river pours into the sea.
I packed it up and went to see what the family was up to on the other side and it was like a different world.
At low tide, pools of water glittered on the mud flats. Rather than concrete and metal of the nest site, it was all water and trees.
The location of the nest was pretty unpicturesque but the fishing grounds were gorgeous and situated in such a way that I thought the parents could keep an eye on the nest while foraging.
If so, both male and female would be able to provision the chicks earlier in the season. The typical osprey nest sees the female standing guard against chick-eating predators for months while the male runs himself ragged feeding the whole family.
If this pair have found a way to do both at once, that would be a significant advantage.
That would make an extremely interesting research project.
The fact that all four birds now spend time at the estuary means they may not be at the nest anymore. They are much more difficult to spot spread out over a large bay than sitting on top of a light standard.
Soon they'll be headed south. Osprey I've watched previously depart in early September for their wintering grounds in central and south America.
I may see them again, or I may have to wait until next spring.