Knot is currently an Amber listed species of conservation concern in the UK although populations are under pressure around the globe. For instance a 2018 census of the American subspecies (rufa) on one of its wintering grounds on Tierra del Fuego, found that numbers have plummeted to an all-time low. The species appears in the UK as a passage and winter migrant with two subspecies, canutus and islandica. 

C canutus tame from PavelT