Justification of Red List Category
This species was previously thought to be undergoing a steep population decline in Europe, but more recently the European trend was re-assessed as unknown. Trends are also uncertain across the core of the breeding range in central Asia. The partly nomadic nature of the species and its fluctuating numbers make assessment of the overall trend problematic, but a moderately rapid decline continues to be suspected on a precautionary basis until better data are available from across the range, and consequently it remains categorised as Near Threatened.
The global population is estimated at 9,000-15,000 pairs (Galushin et al. 2003), equating to 18,000-30,000 mature individuals. The European population is estimated at 300-1,100 breeding females, which roughly equates to 600-2,300 mature individuals (BirdLife International 2015).
A large decline occurred in Europe during 1970-1990 (Tucker and Heath 1994), when up to 30% of birds were lost (particularly from the key population in European Russia), and the species continued to decline in 1990-2000, when overall trends exceeded 30% over three generations (18 years) (BirdLife International 2004). More recently, the European population trend was assessed as unknown in the 2015 European Red List of Birds, with decreases, fluctuations, increases and unknown trends reported for the various range countries (BirdLife International 2015). Europe comprises about 40% of the species’ global breeding range, but holds a much smaller proportion of the global population, as the larger proportion is concentrated in Central Asia, especially in southern Russia and Kazakhstan (Galushin et al. 2003). When last assessed, surveys in the Kustanay Oblast region (northern Kazakhstan) from 1997 to 2004 indicated a fluctuating but ostensibly stable population of 1,500–2,000 pairs, nesting at a density of 9.4–25 pairs per 100 km2 (Bragin 1999, E. Bragin in litt. 2005). No other detailed surveys were known from its Asiatic range, although anecdotal evidence from southern Kazakhstan (Almaty to Chockpack Bird Station) suggested that it was locally abundant (A. Corso in litt. 2005).
The partly nomadic nature of the species and its fluctuating numbers make an assessment of the overall trend problematic, but a moderately rapid decline continues to be suspected on a precautionary basis until better data are available from across the range.
This species breeds primarily in the steppes of Asiatic Russia, Kazakhstan and north-west China. Small populations breed in Azerbaijan, Romania, Turkey and Ukraine. A minority winter in south-east and central Europe, north Africa and the Middle East but most migrate to the Afrotropics and the Indian subcontinent (Thiollay 1994). The global population is estimated at 9,000-15,000 pairs (Galushin et al. 2003). Records in northern and western Europe have increased in recent years, with regular breeding now taking place in Finland and wintering records in several other countries (Ollé et al. 2015).
Assessment of the status of this species is complicated by the fact that on breeding territories numbers fluctuate in response to environmental conditions, probably to changing numbers of small mammals. Thus, high or low territory numbers in any given year or two-year period may be indicative of change in demographics, or they may be indicative of change in local environment, while the birds may breed elsewhere without their population size changing (T. Katzner in litt. 2005). A 13-year data study in north-central Kazakhstan revealed that its numbers and reproductive success vary cyclically, peaking every c. 6 years, in response to interannual variation in local vole densities; these cycles were asynchronous between regions, suggesting a regional redistribution of birds between years (Terraube et al. 2012a).
Reliable records from migration routes and wintering grounds are also difficult to obtain owing to the rarity of the species, its broad-front migration strategy, and difficulties in field identification, although important concentrations of birds have been identified in parts of India and Africa (Galushin et al. 2003).
It breeds in semi-desert, steppe and forest-steppe up to 2,000 m, where its favoured nesting sites are wet grasslands close to small rivers and lakes, and marshlands (Snow and Perrins 1998, Galushin et al. 2003). The species has also been found to breed in agricultural areas, at least when agriculture is non-intensive (Terraube et al. 2009). A minority of the population breeds in the boreal forest and forest-tundra zones, north of its main breeding range (Kuznetsov 1994, V. Morozov in litt. 1999), where it nests in clearings and other open areas (Galushin et al. 2003). Semi-desert, scrub, savanna and wetlands are used in winter (J. Brouwer in litt.). The species is migratory, with most birds wintering in sub-Saharan Africa or south-east Asia. They leave their breeding grounds between August and November and return in March and April (del Hoyo et al. 1994). Birds migrate on a broad front, with only minor concentrations at bottleneck sites (del Hoyo et al. 1994, Ferguson-Lees and Christie 2001). Although birds are most often seen singly, females and juveniles can form parties of 10-15 individuals on migration (Snow and Perrins 1998, Ferguson-Lees and Christie 2001). Birds fly at c.1-9 m above the ground when hunting (del Hoyo et al. 1994, Snow and Perrins 1998) and fly generally higher on migration, but tend to remain from c.1-15 m above the ground (Brown et al. 1982).
Within its breeding range, the species is primarily threatened by the destruction and degradation of steppe grasslands through conversion to arable land, burning of vegetation, intensive grazing of wet pastures and the clearance of shrubs and tall weeds (Galushin et al. 2003, E. Bragin in litt. 2007). Fires are started by farmers, arsonists and dry thunderstorms (E. Bragin in litt. 2007). On its wintering grounds, the species is thought to be negatively affected by the loss of grassland due to burning, cutting and overgrazing (Galushin et al. 2003) and by the use of harmful pesticides, rodenticides and other toxic chemicals (R. Simmons in litt. 1999, Galushin et al. 2003), although this requires further research.
Conservation and research actions underway
It is listed in Appendix II of CITES, Annex II of the Bonn and Bern Conventions and in Annex I of the EU Birds Directive. It is also listed in the Red Data Books of Belarus, Ukraine, Russia and Turkey (Galushin et al. 2003, Kiliç and Eken 2004). It occurs in five state nature reserves in Russia as well as in Naurzum and Korgaljin Nature Reserves in Kazakhstan (Galushin et al. 2003). An International Action Plan for the species was produced in 2003 (Galushin et al. 2003). Recent studies have used ring recovery data, satellite tracking data and environmental niche modelling to improve understanding of the species’ migration routes and wintering areas (Terraube et al. 2012b), and to inform conservation planning in its wintering grounds in Africa (Limiñana et al. 2015).
40-48cm. Narrow winged, lightly built harrier, with similar structure and flight to C. pygargus and females and juveniles closer to C. cyaneus in structure and plumage details. Adult male unmistakeable, with pale grey and white plumage, relieved only by black wing-tips. Adult female dark brown above, streaked below, with barred tail. Similar spp. Adult female can be distinguished from C. pygargus by lack of solid dark trailing edge to inner primaries when seen in flight from below combined with duller secondaries, lack of dark bar along mid-secondaries on upperwing, and a series of subtle characters. Juvenile differs from C. pygargus in having almost white ruff-collar rather than dark neck shawl, same primary pattern as for female and other subtle characters. Female and juvenile C. macrourus also resemble C. cyaneus, but the latter species is larger, with proportionately shorter and broader wings. Voice Little known, but said to be similar to that of C. pygargus and C. cyaneus. Usually silent in winter.
Text account compilers
Symes, A., Taylor, J., Temple, H., Benstead, P., Derhé, M., Ashpole, J, Hermes, C., Capper, D., Khwaja, N., Peet, N., Pilgrim, J.
Morozov, V., Simmons, R.E., Katzner, T., Bragin, E., Brouwer, J., Corso, A.
BirdLife International (2021) Species factsheet: Circus macrourus. Downloaded from http://www.birdlife.org on 22/06/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/06/2021.