The Duck Decoy at Borough Fen has been in use for centuries, although the first reference to it was in 1670. It was originally built to facilitate the capture of ducks which were destined for dinner tables, but now it is used to help capture and ring ducks for conservation purposes. The decoy appears quite remarkable on maps: it is made of a central pond with 8 curved, narrowing arms radiating from the centre. The arms or 'pipes' were tapered and curved so that ducks could be encouraged down them and easily captured. The last known use of the decoy for its original use was in 1951.