This is a video of a little egret.
From Wildlife Extra:
Little egrets breed in Berkshire for the first time, but site future threatened by development
According to the Berkshire Ornithological Club (BOC), little egrets have bred for the first time in Berkshire. But there is a sting in the tail – the breeding place of the fledglings is on a site where plans are in progress to build 7500 houses over the next decade as part of the Kennet Valley Park development. BOC, the Berks, Bucks & Oxon Wildlife Trust (BBOWT) and the RSPB are all concerned about the impacts of this development on nationally important breeding birds, like little egrets and nightingales, as well as other wildlife. This area is the most important heronry in Berkshire and has around 20 annually occupied nests.