Dispersion des Aigles de Bonelli Hieraaetus fasciatus juvéniles bagués en France

The movements of young Bonelli's Eagle have been studied in France since 1990. Chicks are ringed with plastic + metal rings at 40 days, in a population of 28 pairs. From 1990 to 1995, 154 chicks have been ringed, among which 24 were wing-tagged during the first year of the study. The program has resulted in 20 recoveries and 27 sightings of wing-tagged birds. Most sightings and recoveries are concentrated in the French Mediterranean coastal departements : 27 birds were found in the Bouches-du-Rhone, 5 in the Gard, 3 in the Herault, 3 in the Aude, 2 in the Pyrenees-Orientales; three birds were also found in Spain: 2 in the Girona Province, and 1 in the Granada Province. Nevertheless, 5 recoveries or sightings are far outside the breeding range of the species: 2 birds were found in the Gers and 1 in the Ariege (Northern slopes of the Pyrenees), 1 in the Cher and 1 in the Loir-et-Cher (central France). Most of the birds which were recovered or sighted during their first winter did not wander far from their natal place (X 32 km, N = 9), and were concentrated in the Crau plain (Bouches-du-Rhone), where juveniles are observed from August to February. Recoveries of older birds (aged 12 to 24 months) show a pronounced dispersion (X 208 km, N = 6). Six recrutments have been noted since 1992, at an age of 1 to 3 years. On the average, the distance moved between the natal place and the recrutment site is 158 km (50 to 320 km), showing some amount of philopatry. Electrocution on 20 to 60000 volts power lines is the main cause of death of the juveniles, amounting to 85% of the casualities recorded (N = 20).