During the spring and summer grey herons (Ardea cinerea) gather together in nesting colonies and so become less frequent elsewhere in Dorset. There are currently eight known heronries in the county which are surveyed every year and the figures obtained show the grey heron as a declining species. One of these heronries is on Brownsea Island and they are known to be heavy predators of the tern colony and sandwich terns in particular have suffered although measures have been taken to reduce this with some success and the terns have benefited as a result.
In the autumn and winter the birds from the nesting colonies spread out across the county, mainly to coastal sites (Christhurch Harbour, Poole Harbour, Lodmore, Radipole, the Fleet and so on) but they also go to some inland lakes and rivers and you can encounter them just about anywhere there is water.
They stand motionless, like a statue, up to their knees in water waiting for a fish to swim by. Sometimes the prowl slowly around to disturb unsuspecting prey. On cold days they stand hunched up and looking really bad tempered.
It is strange that grey heron numbers should be declining when their cousins, the little egret, are doing so well and their more remote family, spoonbills and cattle egrets are being seen more and more in Dorset.