World status of the Great Bustard (Otis tarda) with special attention to the Iberian peninsula populations

Abstract

The aim of this paper is to review the current world status of this endangered and poorly known species. Its distribution and movement are analysed. The extreme variability of movement patterns (from migrant to sedentary, east to west, along the distribution area) classify the species as a partia1 migrant. A retrospective review shows that Great Bustard populational levels are decreasing, probably due to the increasing isolation of populations. There are only about 22,480-23,860 individuals from east of China to the Iberian peninsula and north-west Africa. The Spanish Great Bustard population may be 43-51% of the world total, Extremadura being the most important nucleus with almost one- fourth of the world population. The spanish population in the last decade is reviewed, showing a decrease in most traditional areas with the exception of Castilla-Leon and Extremadura. On the other hand, seasonal fluctuations in populations sizes denote the possibility of movement among the different populations.