Great Bustard Otis tarda

The Great Bustard is one of the two heaviest flying birds (and animals) in terms of generic males, the other being the Kori Bustard. The Great Bustard has lost much of its former range but is still native to isolated parts of southern and Eastern Europe and western/Central Asia, southern Siberia (the largest population) and China. It is being re-introduced in the wild to the UK.

Males (above) are significantly larger than females, taller with substantially bulkier necks and bodies and may be twice as heavy. A typical male is some 10kg but the heaviest can be closer to 20kg. Individual male Dalmation Pelicans and Mute or Trumpeter Swans may be heavier than individual male Great Bustards but generically the male Bustards are heaviest.

Females, above, are more slender with slimmer necks, but the same cryptic plumage, white body and grey head/neck. (The name "Bustard" comes from the Latin for the bird: "avis tarda").

Unfortunately, I don't yet have a photo of the male's amazing courtship posture and dance in which he fluffs out his moustache and neck feathers while withdrawing his head and body into a bundle of white, raised undertail feathers but the female above seems to be doing a (much less impressive) dance of her own.