Ardeotis kori (Burchell 1822; 1.3 m long) is the extant Kori bustard, the largest flying bird in Africa. A member of the bustard family, Ardeotis nests here with Nahmavis (the basalmost neognath and Otis, basal to mouse birds like Cyrilavis.

Otis tarda (Linneaus 1758) is the extant great bustard, one of the world's heaviest flying animals (up to 40 lbs 18 kg). It has a seven to eight-foot (2.1–2.7m) wingspan. Males are much larger than females with a heavier build whisker-like feathers. The feet are quite small. This genus is restricted to Europe and Asia. It prefers grasslands and is a strong and speedy (up to 98km/hr) flyer.

Burchell WJ 1822. Travels in the interior of southern Africa. Volume 1. Longman, Hurst, Rees, Orme and Brown. London.

Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

wiki/Kori_bustard-Ardeotis
wiki/Great Bustard-Otis