Little bustard  (Tetrax tetrax)

The little bustard is classified as Near Threatened (NT) on the IUCN Red List (1) and is listed on Appendix II of CITES (4) (5).

The pheasant-sized little bustard (Tetrax tetrax), the only member of the Tetrax genus, is the smallest of the Palaearctic bustards. The breeding male is brown on the upperparts of the body and white below, while the head is grey. The neck has a striking pattern of black bordered by white markings, a feature missing in the more drab-looking plumage of the female and non-breeding males. The underside of the female is much darker than in the male, and immature little bustards look very similar to females. When in flight, the wings of this species are extensively white (3).

As ground-dwelling birds, most species of bustard have relatively short toes and strong legs to allow them to run across arid land (6). Both the male and female little bustard are usually silent; however, the male does have a distinctive ‘prrt’ call which sounds like it is blowing a raspberry (3).

The little bustard is split into two widely spread breeding populations (7), which together cover parts of southern Europe, northwest Africa and central Asia (2). In its eastern range, this species occurs in Russia, Georgia, Ukraine, Kazakhstan, Kyrgyzstan, northwest China, northern Iran and Turkey. The western range holds 60 percent of the little bustard’s total population, with the majority being found in Spain and Portugal. Smaller populations within the western range are also found in Italy, France and possibly Morocco (5) (7).

The little bustard historically had a much larger breeding range (3), and has sadly already become extinct in 11 European countries, as well as in Algeria and Tunisia. Its breeding population is thought to be extinct in Azerbaijan (7), though the migratory eastern population of the little bustard still winters there, as well as in Turkey and Iran (5).

The western population of the little bustard winters in the Mediterranean, with the Iberian Peninsula holding the most important wintering quarters for this species. The little bustard is also known to irregularly winter elsewhere in southern Asia. The only remaining migratory population in Western Europe hails from central France, and these birds winter in Spain and Portugal, whereas the Sardinian population is sedentary (5).

Dry, temperate grassland is the preferred habitat of the little bustard (7), which tends to be found in more open areas containing diverse ground cover and some tall vegetation (more than 40 centimetres) in which it can take cover from predators (3) (5).

This species requires a wide variety of habitats for breeding and nesting. The male and female little bustard have different preferences, with the male generally preferring shorter vegetation which allows it to display effectively to females. The female typically prefers taller, denser vegetation to shelter in (5).

In the winter months, the little bustard tends to select agricultural habitats such as winter stubble, fallow land or leguminous crops which have a higher availability of food as well as shelter from potential predators (5).

As an omnivore, the little bustard feeds on invertebrates (2), particularly insects (3) (5), as well as seeds (3). Abundant amounts of insects are required during the chick rearing period (5).

The little bustard has a mating system known as lekking (5), in which the males collectively perform a rather flamboyant courtship display involving foot stamping and leaping through the air (3).

The timing of the breeding season varies depending on the location, but in Spain breeding tends to occur between February and June, while in France it is a little later, generally between May and August (5). The female usually lays three to five eggs per clutch (3), but clutch sizes are known to vary between one and six eggs (5). The nest of the little bustard is a shallow, well-concealed depression in the ground with grassy cover, which is usually found near the territory of the breeding male. The female little bustard is the sole provider of parental care for the chicks, and will incubate the eggs for three weeks. Little bustard chicks are precocial and despite not fledging until 45 to 50 days of age are able to fly at about 20 days old. Some young remain with the female in post-fledging flocks (5). This species is gregarious, gathering together in flocks, particularly in winter (3).

The little bustard has a rather dignified, slow walk, and if frightened or disturbed it will tend to run rather than fly (3).

The main threat to the little bustard is habitat loss (3) (5), primarily as a result of the conversion of its dry grassland habitat into intensive arable land for agriculture. Fragmentation of grassland can negatively affect the quality and availability of the habitat, and can lead to a decrease in male density (7).

Pesticides are thought to be a problem for this species, as their use decreases the availability of insects for food which in turn affects the fecundity and survival of the eggs and chicks. The availability of food for the little bustard is also affected by land use changes. For instance, dense vegetation growing as a result of land abandonment might impair the bird’s ability to search for food, while overgrazing can lead to reductions in the number of insects available (5).

Farm machinery has also been reported to be a threat to the little bustard, either through the destruction of nests or direct mortality of adult and juvenile birds during harvesting. In south-western France, farm machinery is accountable for 40 percent of all clutch failures (5).

Further threats to the little bustard include urban development, hunting and collisions with power lines (5) (7).

The little bustard is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in the species should be carefully monitored (4). It occurs in more than 750 Species Protection Areas (SPAs), and has been included in the national lists of threatened species in all range states. However, despite the large number of SPAs in which it is found, less than half of the breeding population is covered by protected areas (5).

The little bustard is offered some protection through its listing as a Species of European Conservation Concern, European Species of Global Concern, and its Vulnerable European Threat Status. Furthermore, it is classified under Annex I of the EU Birds Directive (8) as well as Appendix II of the Bern Convention, which aims to conserve the wild flora and fauna of the European Continent (9).

In 2001, a European action plan was developed for the little bustard, which aims to achieve a reversal in its current downward population trend by 2020 (5). The number of protected areas established in suitable steppe habitats within Portugal, Spain and France has increased (7).

Proposed conservation measures include improving the management of the little bustard’s habitat within SPAs (5), as well as population monitoring and eliminating dangerous power lines across its range. Further actions, such as working with land-owners to reduce hunting pressures (7), encouraging favourable land management and implementing mitigation measures, would also benefit the little bustard (5) (7).

For more information on the little bustard and other bird species:

• BirdLife International - Little bustard:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=2759