"But these people, (yes, mostly men!) seem to go whizzing around Norfolk to take photos of our numerous and uncommon birds (hen harrier, bittern, egret for example.)"

I guess it depends on the egret, Sen.

Going by the RSPB site, the little egret is a reasonably common sight in Norfolk (and I think both on the Broads and parts of the coastline - even I have seen them) these days.

I guess the great white egret might be one to get the twitchers out though.