The reservoir has always enjoyed a reputation for rare birds. As well as those documented above, it attracted two black-winged stilts in 1918; the first great white egret in London in 1997; the blue-winged teal in 1996; the lesser scaup in 2003; and penduline tits in 1996 and 1997. Remarkably for an inland site, it also attracts rare vagrant warblers, notably the aquatic warbler in 1955, Hume's warbler in 2004 and yellow-browed warblers in several winters since 1994; however, most significant was an Iberian chiffchaff on 3 June 1972, the first recorded in the UK.