Cormorants are a common sight along the riverside at Gainsborough and Morton, especially in winter, and they can sometimes be seen flying over the town centre.
There was a tree on the opposite bank at Morton Turn where Cormorants would often congregate, and most days in the winter months there would be half a dozen or more there. The record was 17 on Jan 21st 2013. This favourite tree of the Cormorants came down in a storm during the autumn of 2017. The tree is still lying there, with its top branches in the water.
The cormorants are still here though, but reduced to ones or twos flying up or down river (including by Mercer Wood)
Cormorant (pictures from Wikipedia)