Migrants and rarities Large numbers of migrants may seek temporary refuge on the marshes, including 2 million sand martins (1968) 5,000 common snipe (1979), 500 ruffs (1989) and 130 red-breasted mergansers (1956). Major rarities recorded include a pied-billed grebe in 1968, a falcated duck, Britain's first, in 1986, and a canvasback in 1997. More recent visitors have included a northern harrier in 2013, a Baikal teal in 2014, an isabelline wheatear in 2016 and a gull-billed tern in 2017. Scarce waders such as pectoral sandpiper, Temminck's stint and red-necked phalarope are almost annual.
migrants and rarities large numbers of migrants may seek temporary refuge on the marshes including 2 million sand martins (1968) 5000 common snipe (1979) 500 ruffs (1989) and 130 red-breasted mergansers (1956) major rarities recorded include a pied-billed grebe in 1968 a falcated duck britain's first in 1986 and a canvasback in 1997 more recent visitors have included a northern harrier in 2013 a baikal teal in 2014 an isabelline wheatear in 2016 and a gull-billed tern in 2017 scarce waders such as pectoral sandpiper temminck's stint and red-necked phalarope are almost annual