Every spring I try to visit the London parks as they have a lot of tame, approachable wildlife. The Grey herons at Regents Park are exceptional. The nest that has been very viewable in recent years does not appear to be in use. At least there was no sign of young and no birds were incubating eggs. This pair did land on it from time to time, but were taking nesting sticks from it to a higher nest near by. From time to time they did display and almost mated.
Grey heron, Ardea cinerea, two birds on nest, Regents Park, London, April 2016. Canon EOS 1dx. 800mm lens. 800 iso. 1/800th at f10.