Great Bustard – Otis tarda

The Great Bustard possibly possesses the widest range of any threatened species of bird, distributed as it is from close to the Atlantic seaboard in Iberia and Morocco across to the Pacific coast of China, a distance of about 10,000 km.

The world population currently includes about 31,000 to 36,000 individuals, 34% less than 16 years ago (Palacin & Alonso 2022). Population declines were recorded in 9 out of 17 countries. According to a study by Mimi Kessler, the global population consists of an estimated 29,060 - 32,449 individuals (Kessler 2022). The majority of the Great Bustard population, around 27,987 to 30,436 individuals, live in Europe (update on the status of the european Great Bustard population during the MOS5 2023 in Bratislava, Slovakia). Not only the world population but also the european population has declined by 1/3 in 11 years.

An increase in the population was only achieved in Germany, Austria , Slovakia and Hungary through protective measures. The centers of occurrence are in central Spain, in the great Hungarian lowlands and in southern Russia. With 22,000 to 24,000 individuals, more than half of the world population is in Spain. Within the MoU countries (signatory states to the Memorandum of Understanding on the Conservation and Management of the Middle-European Population of the Great Bustard), Hungary has the largest population with a maximum of 1,573 individuals in 2022.

Distribution of the Great Bustard open in Google Earth (requires Google Earth installation)

The Great Bustard (Otis tarda) originates in steppe areas. Fossil finds show that bustards occurred in the "polar steppes" of central Europe in the wake of the last ice age. As forests took over in large areas of Europe, suitable habitat for the species shrank significantly. Then, following extensive medieval deforestation, the Great Bustard became a common sight in European agricultural areas, reaching its widest distribution in the 17th and 18th centuries. Around the year 1800, Great Bustards populated Europe's large-scale agricultural landscapes in abundant numbers, breeding from England and Scotland in the west to Denmark and southern Sweden in the north. In Russia, the northern range limit lay some 500 km further north than it does today.

As the medieval system of cultivating arable land in 3-year rotations came to an end, diversity of food resources for Great Bustards decreased. In modern times, especially from the middle of the 19th century on, intensification of agriculture and later the erection of overhead power lines (medium and high voltage) lead to populations in Europe suffering severe declines and many subpopulations becoming extinct. The first populations to die out were those at the range limits in the west (England 1845) and north (Sweden 1862), where in addition to everything else climatic conditions were unfavourable. England embarked on a large-scale reintroduction programme a few years ago.

The West Pannonian population of the Great Bustard showed a marked decline in numbers from a total of at least 3,500 individuals in 1900 to about 130 in 1995. Factors implicated in this decline are habitat changes caused mainly by agricultural transformations and the development of human infrastructures (particularly high and medium voltage power lines), but also hunting pressure.

As a result of intensive and cross-border protective measures the population recovered from the low in 1996 to a population of at least 505 individuals in winter 2014/2015 to 681 individuals in winter 2024.

For many years, Great Bustard populations in Central Europe have been recorded in winter by bustard specialists. In 2017, it was possible for the first time to count Great Bustards in 7 countries (Austria, Czech Republic, Germany, Hungary, Romania, Serbia and Slovakia) with potential breeding populations on the same day. A total of 1,751 Great Bustards were counted, with only 69% of individuals recorded on this day in the eastern part of Pannonia, rather than the usual 90-95% (Table 2, Figure 1). Despite repeated efforts, it was not possible to carry out synchronised counts in all countries between 2018 and 2020. The reason for this was the mostly mild winters and the associated impassable field roads, which usually prevented a census of the eastern Pannonian population. In 2021, the census period was therefore significantly extended in order to be able to record at least 90 % of the individuals actually occurring in Central Europe. A total of 2,252 individuals were counted. In 2023, only some countries were counted.

The results in 2024 again show a slight increase in the Central European population. A total of 2,723 people were counted, which represents an increase of approx. 11% (2022-2024). The strongest relative increase was recorded by the East Pannonian population, which grew by approx. 16% (2022-2024). The West Pannonian population grew by approx. 7% (2022-2024) and the German population decreased slightly by approx. 4%. This means that the Central European population increased by approx. 56% from 2017 to 2024.

Table: Numbers of Great Bustard on synchronous winter count

Source: Raab et al. (2010) and own data.

Austria's bustard population is located at the northwestern edge of the third largest European distribution "cluster" of Great Bustards in the Great Hungarian Plain. The Austrian population is centred around the Western Weinviertel, the Marchfeld and the Rauchenwarther Platte in Lower Austria, and the Heideboden, the Parndorfer Platte and the Hanság / Seewinkel in Burgenland.

Overall, the population of Great Bustards in Austria declined from around 700-800 individuals towards the middle of the 20th century (1942) to 150-170 individuals in the early 1970s (1970-1972) and around 100 individuals at the end of the 1970s (1978) to around 60 individuals towards the end of the century. By the 2010 breeding season, five years after the start of the first LIFE project for Great Bustard conservation, the breeding population had risen to 317-343 individuals. In 2015, the breeding population of Great Bustards in Austria was already at 335-464 individuals, in 2020 at 547-670 individuals and in 2024 at 580-681 individuals.

Since 1995, numerous special bustard conservation areas have been established in Austria as part of the ÖPUL agri-environmental programme (Austrian programme for the promotion of environmentally friendly, extensive agriculture that protects the natural habitat). In the period from 1995 to 2000, they totalled around 300 ha and increased to over 2,000 ha since 2002. In the following years up to and including 2022, the number of special protection areas for the Great Bustard fluctuated between approx. 6,000 and approx. 7,000 ha. In 2024, more than 8,000 ha were specially designated bustard conservation areas. Parallel to the increase in special bustard conservation areas, the Austrian bustard population has also increased significantly over the last two decades.

Table: Development of Great Bustard numbers (individuals) in Austria by sites.

Source: Raab et al. (2010) and own data.