A slim, medium-sized eagle, with rounded, rather short, wings and a long tail. The dark upper side contrasts strikingly with the clear white under side, the spots being hardly visible at a distance. In flight the wings appear dark in contrast to the white body below, and have a white leading edge, a blackish bar at the base of the flight quills, a conspicuous grey patch at the carpal joint, and a dark trailing edge contrasting with the paler flight quills. Immatures are more difficult to distinguish from other medium-sized brown eagles, but the pale chestnut under side is a good guide.
In Europe Bonelli’s Eagle is restricted to the Mediterranean regions. It lives in mountainous areas and other rugged terrain at medium to low altitude – sea level to 1500 m, averaging 660 m with only 11 % of pairs nesting above 1000 m. It tends to prefer short or sparse vegetation, such as garigue, dry grassland and rocky habitats but the vegetation cover of its habitat can be highly variable including forests and parkland as well as bushes and scrub. It is also often found in mosaics of open habitat with non-intensive crops, vineyards, olive groves, non-irrigated orchards, small woodlands and pasture. The average distance between pairs is 11.9 km although neighbouring pairs may breed only 2 km apart.
The Bonelli’s Eagle Hieraaetus fasciatus is endangered at a European level having undergone large declines throughout almost all of its European range between 1970 and 1990, reducing the population to 862-1072 breeding pairs.
The declines have exceeded 50% over twenty years in some areas and in Spain, which holds up to 65% of the European population, the population appears to have declined by 25% from 1980 to 1990. This downward trend is contrary to that of other big eagles, such as the Spanish Imperial Eagle and Golden Eagle, whose populations are either stable or recovering. It is thought to be due to persecution, electrocution by powerlines, disturbance at nest sites and loss and deterioration of dry grassland and garrigue habitats. The global population is not concentrated in Europe. In Europe the species irregularly distributed in the Mediterranean basin. The global range of the Bonelli’s Eagle extends from the Iberian Peninsula and NW Africa across southern Europe, the Middle East and Arabian Peninsula through Afganistan to India, south China and Indonesia. The birds of Europe are sedentary, and the population of the European Union can be estimated at 800-900 breeding pairs.
The Bonelli’s Eagle preys on medium-sized mammals and birds of a wide range of species. Rabbits and partridges are the preferred prey but it also preys on hares, squirrels, rodents, pigeons, corvids and lizards. In recent years, declines in both rabbits and partridges have caused diet changes and less profitable prey is becoming important. Carrion feeding is rare.
This species has a large global range; the total size has not yet been quantified, but the Extent of Occurrence in Africa alone is estimated to be 510,000 km2. It has a large global population estimated to be 10,000-100,000 individuals (Ferguson-Lees et al. 2001). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]
The stick nest is usually located on rocky cliffs, rarely on trees, and over the years it can reach a huge size. Laying extends from early January to mid April but most clutches are laid between mid February and mid March. Normally two eggs are laid, sometimes one and rarely three, with an average clutch size of 1.9. Incubation is mainly by the females and lasts 37-40 days. The fledging period is 61-77 days and the juveniles stay in the parental territory around 12-16 weeks before reaching independence. Breeding success is high (82 %), though 30 % of the pairs do not lay. Productivity is 0.82 chicks/pair and 1. 56 fledging per successful nest but there are appreciable differences between years and regions.
Resident and dispersive. Adults present all year in loose vicinity of breeding area, though less attached to territory July-November. In Europe, young become independent July to early August and soon leave nest vicinity, though occasionally remain in area into October or even later. Dispersal mainly southward, and some appear late summer in low-lying areas along Mediterranean. In central and south Spain, frequently seen autumn-winter 25-50 km from nearest possible nesting localities. Irregular occurrences west and north France, and rare vagrants further north, also mainly July-December. Slight evidence of southward autumn movement across Mediterranean; few birds involved, and probably continuance of dispersal rather than migration.
- spanwidth min.: 145 cm
- spanwidth max.: 165 cm
- size min.: 55 cm
- size max.: 65 cm
- incubation min.: 37 days
- incubation max.: 40 days
- fledging min.: 50 days
- fledging max.: 55 days
- broods 1
- eggs min.: 1
- eggs max.: 3
- Conservation Status
- Aquila fasciata renschi
- Lesser Sundas
- Aquila fasciata fasciata
- n Africa and s Europe to s China and Indochina
- Aquila fasciata
- EU, OR Spain to India to s China, also n AF