The Whooper Swan (Cygnus cygnus) is the wild swan with the trumpeting call, distinguished from the Mute Swan by its yellow-and-black bill — yellow covering more than half the bill — a flat head with no knob, and a neck held straight and vertical rather than in an S-curve. It is a very large bird, 140–165 cm long with a wingspan of 205–243 cm and a weight of 8–15 kg.
Its deep, trumpeting "hoo-hoo hoo-hoo" call carries for 2–4 km and is unmistakable, given both on the water and in flight, where flocks call continuously as their wings produce a whirring sound. The Whooper Swan breeds across Sweden, from the lakes of Skåne to the mires of Lapland, densest in the north, building a large, mound-shaped nest of reed and vegetation directly at the water's edge that the pair reuses year after year; the female lays 4–6 large, greenish-white eggs, incubated by both parents for 35–40 days, and the precocial cygnets leave the nest within a day, staying with their parents for three to four months and often into the following winter. It feeds on aquatic plants in summer, tipping up like a dabbling duck to reach the bottom, and switches to waste grain and winter crops on farmland in autumn and winter, when it may eat 2–3 kg of vegetation a day. While largely migratory, increasing numbers now overwinter in Sweden wherever open water and pasture remain available, and the population — boosted in winter by birds from further north and Iceland — is estimated at 7,000–10,000 breeding pairs, with classic gathering sites including Hornborgasjön, Tysslingen, Kvismaren and Falsterbo.
Read about this species in Swedish →