Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The European population is estimated at 814,000-1,390,000 pairs, which equates to 1,630,000-2,770,000 mature individuals (BirdLife International 2015). Europe forms approximately 75% of the global range, so a very preliminary estimate of the global population size is 2,170,000-3,690,000 mature individuals, although further validation of this estimate is needed. It is placed in the band 2,100,000-3,700,000 mature individuals.
Behaviour Populations in Scandinavia and most of the former Soviet Union are migratory, wintering in Africa and southern Asia. Those elsewhere are resident (del Hoyo et al. 1994). Migrants move south between August and November and make the return journey between February and May. Birds tend to occur singly or in pairs, sometimes forming small family groups at roosts. However, they can migrate in groups, and as birds avoid sea crossings (and even freshwater bodies) as far as possible, they form huge concentrations at peninsulas and narrow straits (Brown et al. 1982, Snow and Perrins 1998, Ferguson-Lees and Christie 2001). Migration is strictly diurnal, and also often follows mountain ranges and ridges (Brown et al. 1982). Habitat It inhabits a wide variety of habitats but requires at least some tree cover for nesting and roosting; ideal habitat appears to be forest edge, or mosaics of forest and open areas (del Hoyo et al. 1994). Diet It is versatile depending on the prey animals available, with small mammals usually predominating, but in some areas invertebrates making up the majority (del Hoyo et al. 1994). Breeding site The nest is built on a fork or branch of a large tree, usually near to forest edge (del Hoyo et al. 1994). Management information Although versatile in its habitat choice, trees are required particularly on its breeding grounds (del Hoyo et al. 1994).
In the U.K., it suffered a significant reduction in available prey in the 1950s when a myxomatosis epidemic killed off c.99% of the rabbit population. The most important historical threat though has been from persecution, including through poisoned bait traps, with pesticides and habitat loss also causing some declines (Orta et al. 2015). It is highly vulnerable to the impacts of potential wind energy developments (Strix 2012). Ingestion of lead shot may also be a threat (Battaglia et al. 2005).
Text account compilers
Calvert, R., Khwaja, N., Taylor, J., Symes, A. & Ashpole, J
BirdLife International (2017) Species factsheet: Buteo buteo. Downloaded from http://www.birdlife.org on 23/11/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/11/2017.