Resumen de Poliàndria en l'Àliga Perdiuera (Hieraaetus fasciatus)
A pair of Bonelli's Eagles, monitored since 1982 in the Alt Camp (Catalonia, NE Spoin), fledged a mean of 1.4 birds per year. From 1989 to 1993, the female laid 2-3 eggs per clutch, but they were repeatedly infertile. In 1993, an subadult male was occasionally seen around the nest site, where it was tolerated by the pair. In 1994, the subadult individual clearly joined the pair. Jhe two males were seen to perform joint flights, and to drive off on intruding immature male. Jhe female and the two males were also seen simultaneously on the nest site on several occasions, and offen the two males were observed to abandon the nesting cliff together. In this same year, the presumably polyandrous female reared a chick successfully.
