British Columbia, Canada
Two adult Trumpeter Swans ( Cygnus buccinator ) and a juvenile in a mountain lake. They are North America's heaviest flying bird. To get that much mass aloft the swans need a 100 metre long 'runway' of open water. When they run hard across the surface they sound like galloping horses as they generate speed for takeoff. Trumpeters are assumed to mate for life, but some individuals do switch mates over their lifetimes.