Argentavis magnificens is an extinct bird from the late Miocene (23 - 5 million years before present) of South America. It is the largest flying bird ever discovered, and is sometimes known as the Giant Teratorn.

Physical characteristics

• wingspan: 8 m
• wing load: 1E2 Pa (estimated)
• length: 3.5 m
• height: 2 m
• weight: 80-100 kg (estimated)

For comparison, the living bird with the largest wingspan is the Wandering Albatross (Diomedea exulans), and it reaches 3.5 m. Since A. magnificens was believed to be a land bird, another good point of comparison is the Andean Condor, Vultur gryphus, which some believe is a relative of Argentavis. This bird has a wingspan of about 3 m and is among the largest land birds.

The heaviest extant flying bird is not heavier than 20 kg (several contenders, among which the European Bustard Otis tarda and the African Kori Bustard (Ardeotis kori)).

Behaviour

As with all extinct species not much can be known about the Giant Teratorn's behaviour. From the size and structure of its wings it is inferred that A. magnificens flew mainly by soaring, using flapping flight only during short periods. It is probable that it used thermal currents and the prevailing westerly winds that swept across the region (there were no important mountains in South America at the time) . It has been estimated ([1] (http://www.ciencias.uma.es/publicaciones/encuentros/ENCUENTROS64/aves.html) (Spanish)) that the minimal velocity for the wing of A. magnificens is about 11 m/s or 40 km/h.

References

[1] Is there a limit to body size in flying birds? (http://www.ciencias.uma.es/publicaciones/encuentros/ENCUENTROS64/aves.html) (Spanish)