Great Bustard - Behavior

Behavior

This species is gregarious, especially in winter when gatherings of several dozen birds may occur. Male and female groups do not mix outside of the breeding season. The Great Bustard has a stately slow walk but tends to run when disturbed rather than fly. Running speeds have not been measured but adult females have been known to outrun red foxes, which can reach a trotting speed of 48 km/h (30 mph). However, they can be fairly strong fliers as well, especially during seasonal movements, and can reach speeds of up to 80 km/h (50 mph) in flight. Both sexes are usually silent but can engage in deep grunts when alarmed or angered. The displaying adult male may produce some booming, grunting and raucous noises. The female may utter some guttural calls at the nest and brooded young make a soft, trilling call in communication with their mothers. The Asian and Russian populations of the species are migratory and will gather in large numbers at pre-migratory sites in order to move collectively to winter grounds. In the remainder of the range, such as Central Asia, only partial migrations may occur based on seasonal food availability. In the Iberian Peninsula, bustards that engage in migration seem to choose different periods for movements based on sex. No population is known to use the same grounds for wintering and summering.