Little Bustard Tetrax tetrax breeds from Morocco and Iberia to France and Italy, and from Ukraine and SW Russia through Kazakhstan to NW China and N Iran, and winters from the Mediterranean zone through Turkey and Transcaucasia to Iran, and erratically elsewhere in S Asia (Collar et al. 2014). It is currently listed as Near Threatened, because when last assessed it was thought to be undergoing a moderately rapid population decline.
Globally, it has an extremely large range in the breeding season (>5 million km2) and a large range in winter (c. 1 million km2), and hence does not approach the thresholds for Vulnerable under the range size criteria (B and D2). Its population size is also very large (with 122,000–240,000 mature individuals in Europe alone; BirdLife International 2015), and hence does not approach the thresholds for Vulnerable under the population size criteria (C and D1). Therefore, the only potentially relevant criterion is A, which relates to reductions in population size. Until recently, the population was thought to be declining moderately rapidly, at a rate approaching the threshold for listing as Vulnerable under criterion A (at least a 30% decline over ten years or three generations, whichever is longer), based largely on trend data collated from across its European range for the period 1990–2000 (BirdLife International 2004).
New data collated from across Europe for the European Red List of Birds (BirdLife International 2015) indicate that the species has continued to decline significantly in recent years, and that this decline is ongoing. A combination of official data reported by 27 EU Member States to the European Commission under Article 12 of the EU Birds Directive and comparable data from other European countries, provided by BirdLife Partners and other leading national ornithologists, suggests that the European breeding population has declined overall by 35–40% over the last three generations (30.9 years, based on a generation length estimated by BirdLife to be 10.3 years), especially in Spain, which holds c. 70% of the European population. Consequently, the species is now classified as Vulnerable at European level (BirdLife International 2015).
Based on its distribution, Europe holds around 40% of the global breeding range, with most of the remainder in Kazakhstan. Based on its abundance, however, Europe probably holds around 80-90% of the global population (with only c. 20,000 individuals in Kazakhstan; N. Petkov in litt. 2012), so the decline in Europe is of global significance. It is possible that the numbers breeding in SW Russia and Kazakhstan have been underestimated, as large wintering flocks (some comprising tens of thousands of birds) have been recorded in Azerbaijan (Gauger & Heiß 2010), and 5,000-10,000 birds are estimated to winter in Iran (Sehhatisabet et al. 2012). However, it is also possible that the Central Asian population is declining, owing to the threats posed by factors like agricultural change (e.g. Kamp et al. 2011) and power lines (e.g. Voronova et al. 2012), which have already contributed to the declines observed in western Europe.
Given the information that is available, and the strong decline in its core European range, the species appears to qualify to uplisting to Vulnerable under criterion A.
Comments on this proposal are welcome, along with any data regarding the recent trend of its breeding and wintering populations in Central Asia, Transcaucasia and the Middle East, along with any additional information about the threats currently affecting this species across its range.
BirdLife International (2004) Birds in Europe: population estimates, trends and conservation status. Cambridge, UK: BirdLife International (Conservation Series No. 12).
BirdLife International (2015) European Red List of Birds. Luxembourg: Office for Official Publications of the European Communities. http://www.birdlife.org/datazone/info/euroredlist
Collar, N., Garcia, E.F.J. & de Juana, E. (2014). Little Bustard (Tetrax tetrax). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2014). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. www.hbw.com
Gauger, K., and Heiß, M. 2010. Winter trip 2010: Birdwatching news and bird photography from Transcaucasia. http://birdingaze.blogspot.com/search?updated-min=2010-01-01T00:00:00%2B01:00&updated-max=2011-01-01T00:00:00%2B01:00&max-results=2
Kamp, J., Urazaliev, R., Donald, P. F., & Hölzel, N. (2011). Post-Soviet agricultural change predicts future declines after recent recovery in Eurasian steppe bird populations. Biological Conservation, 144(11), 2607-2614.
Sehhatisabet, M. E., Abdi, F., Ashoori, A., Khaleghizadeh, A., Khani, A., Rabiei, K., & Shakiba, M. (2012). Preliminary assessment of distribution and population size of wintering Little Bustards Tetrax tetrax in Iran. Bird Conservation International, 22(03), 279-287.
Voronova, V. V., Pulikova, G. I., Kim, K. K., Andreeva, E. V., Bekker, V. R., & Aitbaev, T. (2012). The Impact of Power Lines on Bird Mortality in Central Kazakhstan. Raptors Conservation 24: 52-60