Great Bustard

The great bustard is the only living species in the genus Otis and shows an extraordinary size difference between the sexes. Adult males are around 115 centimetres long, span 210–270 centimetres and weigh 5.8–18 kilograms. Females are roughly a third smaller in linear dimensions, about 90 centimetres long with an approximately 180-centimetre wingspan, and weigh 3.1–8 kilograms. Mature males also carry long beard-like feathers, adding to the unmistakably heavy appearance of this large ground bird. (Wikipedia, general species account)

Great bustards breed in open grasslands and farmland from northern Morocco and parts of Europe east through temperate Central and East Asia. European populations are mainly resident, whereas Asian birds move farther south for winter. The species walks with a notably slow, deliberate manner, a trait echoed in the Latin name tarda. Although it spends much of its life on the ground and nests there, it remains capable of sustained flight despite the male's exceptional mass. Mongolia is included within its native range. (Wikipedia, general species account)