The gadwall is the Royal National City Park’s rarest duck and breeds in southern and central Sweden. The species has one of its strongest holds in the country in the Mälaren region, including the park. Good places to find the species are on the Fjäderholm islands, Isbladskärret, Lappkärret and nowadays also Brunnsviken. The gadwall is often overlooked since the female is similar to the female mallard. The male is however more discreetly grey-black than its relatives, such as the mallard, widgeon and teal, who flaunt their colours during the mating season. Bird watchers recognise the gadwall in flight from its typical white wingspread and the male’s snoring call. The female sometimes lets out an intensive repetitive cry which has given rise to its name
meaning ‘shouting duck’.