Great Bustards are the most emblematic species of the plains and can be found quite easily near Trujillo. The males are huge (sometimes weighing 15 kgs) and in March and early April will form leks when males display to attract females. These are spectacular sights, with the males twisting their wings to make their bodies look like massive white balls, as well as inflating their necks to form big orange-coloured balloon-like pouches. A lek can be spotted from a great distance as the white of displaying males will contrast against the vivid green of the pasture. Once the display period is over, from late April, the males will form small groups whilst the females take sole responsibility for raising the young. Outside the breeding season, the birds will remain in small parties.