Common name: Great Bustard
Scientific name: Otis tarda
Taxonomy: Order Gruiformes, Family Otididae
Phenology: Resident species
National Threatened (Red Book of the Vertebrates of Portugal)
Global Vulnerable (IUCN)
National 1.435 individuals
Global 31.000 to 37.000 individuals
Distribution: Wide, but very fragmented. It goes from the North of Africa and Iberian Peninsula through the Central and Southern Europe to the most Oriental part of China.
Habitat: Typical bird of open areas. Occurs on natural steppes, pastures and extensive dry farming areas with crop rotation – fallow lands and low density crops.
Characteristics: Large ground bird. It presents accentuated sexual dimorphism, being that the males are 2 to 4 times heavier, sometimes weighing up to 16 kilos and being 50% larger than females. Total length is between 75 and 105 cm, and the wingspan between 190 and 260 cm. Adult males present grey head and neck, both being equally large. During spring time they present “moustaches” and a dark brown and red collar on the neck, which fades in the summer. The dorsal feathers are of a reddish-brown colour with irregular black stripes. The females are fairly smaller than the males and have a thinner neck. The feathering is similar to the one on the male but paler. Juveniles are generally similar to females, although the juvenile males are larger.
Feeding: Green spontaneous plants, seeds and invertebrates.
Social behaviour: They occur in droves of variable dimensions.
Breeding: Occurs between the end of March and June. With the end of winter the males move to specific areas where they engage in courtship behaviour - Lekking. The females visit these areas and select a male to mate. After copulation the females move to the nesting areas, generally crops or high fallow lands were they will lay 2 to 3 eggs on the ground. The hatchlings appear after a period of 21 to 28 days of incubation. They are nidifugous, abandoning the nest shortly after they were born and feeding out of insects.
Threats: Agricultural intensification and increasing human pressure are the main threat factors. These factors result in habitat loss and fragmentation due to the disappearance of fallow lands, increase of cattle density, afforestation of farming areas, increase of irrigated crops and proliferation of roads and power lines. Other factors, such as farm mechanization and use of pesticides contribute for the increase of egg, hatchling and juvenile mortality.