Snettisham RSPB Norfolk
Snettisham RSPB Reserve on The Wash in northwest Norfolk is the site of one of the most spectacular wildlife events regularly witnessed in Britain, a tidal roost of wading birds in which up to 300,000 knot, dunlin and other species are compressed by the advancing tide onto a narrow strip of shingle in a display of aerial acrobatics that is one of the defining wildlife spectacles of the British calendar. The reserve has become one of the most visited RSPB sites in England specifically for this event, and the experience of watching the knot flocks performing their synchronised manoeuvres at close range is one that repeatedly generates expressions of genuine awe from observers. The roost is at its most spectacular around high tide when the birds are forced from the tidal flats by the rising water and compress onto the shingle ridges of the reserve in ever-denser concentrations. The movements of huge numbers of birds in tight, synchronised flocks, twisting and turning in formations that create shifting grey and silver patterns against the sky, are driven by the individual responses of each bird to its neighbours, producing a collective behaviour of extraordinary visual complexity from simple local rules. The timing of the roost depends on the tidal cycle and the best displays are at the highest spring tides of the year. The reserve also supports breeding and wintering wildfowl and waders in considerable variety, and the shingle beaches provide nesting habitat for oystercatchers, ringed plover and little terns. The wider landscape of The Wash, the largest tidal estuary system in Britain, provides context for the reserve's wildlife in one of the most important wetland systems in northern Europe.