The great bustard (Otis tarda) is a bird in the bustard family, the only member of the genus Otis. It breeds in open grassland and farmland in southern and central Europe, and across temperate Asia. European populations are mainly resident, but Asian birds move further south in winter. Portugal and Spain now contain about 60% of the world's population. It became extinct in Great Britain when the last bird was shot in 1832. Recent attempts to reintroduce it into the UK have met with limited success and there is a population of 40 birds on the UK Army training area, Salisbury plain. Here the lack of public access allows them the freedom needed as a large ground nesting bird. It is classified by the IUCN as "vulnerable".