Justification of Red List Category
This species is listed as Near Threatened because it is probably experiencing a moderately rapid overall population decline, driven by rapid declines in the west of its range, owing mainly to habitat loss and degradation, as well as low-level hunting pressure; it almost meets the requirements for listing as threatened under criteria A2abcd+3bcd+4abcd. Recent increases in the east of its range are so far unquantified and require further study.
The global population (excluding c.20,000 individuals in Kazakhstan) was previously estimated at a minimum of c. 240,000 individuals (C. Martínez in litt. 1999). The European population alone was recently estimated to be 122,000-240,000 mature individuals (BirdLife International 2015). The eastern population is likely to be of a similar size to the Iberian population (J. Kamp in litt. 2015). The population is therefore placed in the band 100,000-499,999 individuals.
The European population is estimated to be declining by 30-49% in three generations (30.9 years) (BirdLife International 2015). There is little evidence to suggest that the population in Kazakhstan has declined, as surveys in central and northern Kazakhstan show that densities did not decrease between 2008-2009 and 2015 (J. Kamp in litt. 2015). Wintering flocks in Azerbaijan are not thought to have declined (J. Kamp in litt. 2015). Europe holds around 40% of the global breeding range, but may hold as much as 80-90% of the global population. The Central Asian population may be exposed to the same threats as the western European population, e.g. agricultural change and power lines (Kamp et al. 2011, Voronova et al. 2012). Thus, the overall population is estimated to be in moderately rapid decline.
This species has two widely separated breeding populations. In its eastern range it occurs in Russia (likely to have been previously underestimated at 9,000 displaying males, as 14,000-17,000 individuals were reported in one region alone [Orenburg] in the last two years [A. Antonchikov in litt. 2012]), Georgia (60 non-breeding individuals [E. García in litt. 2007]), Kyrgyzstan, Kazakhstan (c.20,000 individuals and likely to be increasing [N. Petkov in litt. 2012] although this is thought to be an underestimate [J. Kamp in litt. 2015]), Ukraine (100-110 individuals [Y. Andryushchenko in litt. 1999]), north-west China, northern Iran and Turkey (5-50 breeding males [BirdLife International 2015]). Its western range covers Spain (71,000-147,000 individuals comprising 41,482-86,195 breeding males [García de la Morena et al. 2006, BirdLife International 2015], down from 100,000-200,000 males in the 1990s [De Juana and Martínez 1996]) and Portugal (5,546-13,207 breeding males [Silva unpubl. data], down from 13,250-21,771 breeding males in 2003-2006 [BirdLife International 2015]), with smaller populations in Italy (352 breeding males [BirdLife International 2015]), France (1,350-2,350 displaying males [BirdLife International 2015]) and Morocco (possibly only in the tens of individuals following a decline towards the end of the last century [Palacin and Alonso 2009]).
Eastern populations winter from Turkey and the Caucasus to Iran (estimated 5,000-10,000 wintering birds [Sehhatisabet et al. 2012]), and erratically elsewhere in south Asia. Azerbaijan holds the main wintering quarters (over 150,000 individuals in 2005-2006 [E. García in litt. 2007, Gauger 2007], more than 100,000 in autumn 2011 [Heiss 2013], and more than 100,000 in February/March 2012 [P. Simeonov to P. Goriup in litt. 2012]) with sightings in the winter of 2010 report 25,000 and 50,000-70,000 individuals in Adjinohur valley and Shirvan National Park respectively (Gauger and Heiß 2010), and 41-48% of the total population using the Besh Barmag Bottleneck (Heiss 2013). Western populations winter in the Mediterranean zone, with the Iberian peninsula holding the most important wintering quarters (a minimum of 16,429-35,929 and 11,200 individuals in Spain and Portugal, respectively) (E. García in litt. 2007).
The global population (excluding Kazakhstan) was estimated at a minimum of c.240,000 individuals in the late 1990s (C. Martínez in litt. 1999) and the latest European assessment estimated 122,000-240,000 mature individuals (BirdLife International 2015). Whilst it remains widespread and numerous, in some parts of its range it has declined dramatically since the 19th century, leading to extinctions in at least 11 European countries, Algeria, Tunisia and probably as a breeding bird in Azerbaijan. The species has now disappeared from mainland Italy, where it occurred in Apulia, and it is presently declining strongly in Spain (46% decline between 1998 and 2012 [BirdLife International 2015]), and Portugal (47% decline between 2003-2006 and 2016 [Silva unpubl. data]). Eastern populations are said to have increased in recent years (E. García in litt. 2007). The population in the Eurasian steppe belt is thought to have recovered due to large scale land abandonment following the break up of the former Soviet Union in 1991 (Gauger 2007, Kamp et al. 2011).
This species inhabits dry grassland and, in Europe, it also occurs in areas of low-intensity arable cultivation and pastoral land, selecting areas with a high diversity of ground cover such as mosaics of pasture, stubble fields, long-rotation fallow land, legume and cereal crops (Morales et al. 2013, Santos et al. 2016). It prefers large fields in areas with high plant species richness providing high arthropod abundance, which is important for male displaying and female breeding sites (Silva et al. 2010, Faria et al. 2012, Silva et al. 2014). Males display at lek sites, and females may breed close to the lek sites (Tarjuelo et al. 2013). In Spain, early-laid clutches have a greater chance of success, possibly associated with different ranging patterns, which depend on arthropod availability (Lapiedra et al. 2011). The species has been observed to form mixed-species flocks with Pin-tailed Sandgrouse Pterocles alchata in Iberian regions and France (Martin et al. 2010). Wintering birds in Azerbaijan prefer semi-desert and steppe areas under winter pasturing, and avoid areas of intensive agriculture (Gauger 2007).
The primary cause of its decline has been conversion of dry grassland and low-intensity cultivation to intensive arable agriculture, especially where this has included the planting of monocultures or perennial crops, irrigation or afforestation. The fragmentation of traditional habitats, by means of agricultural intensification or infrastructure development, negatively affects habitat availability and quality for the species, as well as male density (García et al. 2007, E. García in litt. 2007) as displaying males exhibit a preference for old and same-year fallows which offer shelter and food (Delgado et al. 2010). The use of pesticides could reduce food availability (E. García in litt. 2007). Harvesting with modern farm machinery, operated at high speed and often during the night, is the key threat to females and nests in Europe and is the cause for the observed male-biased sex structure and low fecundity (Iñigo and Barov 2010, Lapiedra et al. 2011). Farm machinery accounts for 40% of clutch failure in southwest France (Inchausti and Bretagnolle 2005).
Conversion to intensive arable agriculture continues to be the primary threat and cause of continuing declines in Europe (E. García in litt. 2007) and is predicted to cause declines in the eastern population in the near future (Kamp et al. 2011). It also suffers from illegal hunting (Y. Andryuschenko in litt. 1999), although this is a minor threat (V. Bretagnolle in litt. 2007). The collision of birds with overhead powerlines is a locally important cause of mortality (E. García in litt. 2007), and the possibility of collisions with aircraft has created conflict and resulted in the culling of individuals in France in 2013 - although this was lately stopped (Anon. 2013). The release of farm-reared gamebirds could eventually introduce new pathogens to wild populations of T. tetrax (E. García in litt. 2007). In Azerbaijan, the main threats are disturbance from intensive land use (mainly heavy grazing), habitat loss to infrastructure development and probably hunting, with individuals shot and sold along roadsides (Gauger 2007, P. Goriup in litt. 2016). Climate change effects could lead to shorter rainy seasons and reduced winter precipitation in Southern Europe, which could have a detrimental effect on habitat quality for the species (Delgado et al. 2009, Delgado and Moreira 2010).
Conservation and Research Actions Underway
CITES Appendix II. EU Birds Directive Annex I. A European action plan was published in 2001 (E. García in litt. 2007), its implementation reviewed in 2010 (Barov and Derhé 2011) and updated in the same year (Iñigo and Barov 2010). A species action plan for the species in Sardinia is in preparation. In Catalonia, Management Plans for the SPA with a Little Bustard population have been developed. The species has been the subject of several LIFE Nature projects in Portugal, Spain, France and Italy. France and Spain have attempted a joint programme of reinforcement of the populations in Central and Western France by release of captive-bred chicks during 2006-2009. In France, targeted agri-environmental measures (MAET) have been developed and tested in the region of Poitou-Charentes. Management agreements have been elaborated and signed with farmers, which are believed to have led to an increase of the affected populations (Leitão et al. 2006, Bamière et al. 2011, Bretagnolle et al. 2011). In France, Spain and Portugal national census takes place every five (four in France) years. The number of protected areas established in steppe habitats in those countries has increased.
Conservation and Research Actions Proposed
Carry out coordinated surveys to obtain an up-to-date estimate for the total population. Continue to conduct surveys to monitor population trends. Preserve habitat and alter land-use practices through EU and national policies. Work with land-owners to manage land favourably. Reduce hunting pressure through awareness campaigns. Ensure fields with permanent cover on arable land through agri-environmental schemes using rotations and fallow land. Eliminate dangerous powerlines.
Text account compilers
Capper, D., O'Brien, A., Ashpole, J, Taylor, J., Westrip, J., Derhé, M.
Antonchikov, A., Simeonov, P., Bretagnolle, V., Petkov, N., Andryushchenko, Y., Jolivet, C., García de la Morena, E., Praveen, J., García, E., Kamp, J., Martínez, C., Leitão, D., Goriup, P.
BirdLife International (2019) Species factsheet: Tetrax tetrax. Downloaded from http://www.birdlife.org on 22/10/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/10/2019.