The trumpeter swan is the largest extant species of waterfowl. Adults usually measure 138–165 cm (4 ft 6 in–5 ft 5 in) long, though large males can exceed 180 cm (71 in) in total length. The weight of adult birds is typically 7–13.6 kg (15–30 lb). Possibly due to seasonal variation based on food access and variability due to age, average weights in males have been reported to range from 10.9 to 12.7 kg (24 to 28 lb) and from 9.4 to 10.3 kg (21 to 23 lb) in females. It is one of the heaviest living birds or animals capable of flight. Alongside the mute swan (Cygnus olor), Dalmatian pelican (Pelecanus crispus) and Andean condor (Vultur gryphus) and the kori bustard (Ardeotis kori), it is one of the handful to scale in excess of 10 kg (22 lb) between the sexes and one survey of wintering trum