The whooper swan (Cygnus cygnus) is Sweden's largest waterbird and one of the most recognisable sights on the country's lakes and coastal bays from autumn through early spring. Unlike the resident mute swan, the whooper is a true migrant, arriving in numbers as the days shorten.
Look for the straight neck (held upright, not curved like a mute swan's), the black-and-yellow bill pattern, and the loud, bugling call that carries for a kilometre or more across still water. Juveniles carry a dusty grey-brown plumage well into their first winter.
Family groups stay together through the winter — cygnets are easy to pick out by their grey plumage and pink-based bills, still travelling with both parents well into the new year. A skein in flight, necks outstretched and wingbeats synchronised, is one of the quieter satisfactions of the season.