Two female Bonelli's Eagles successfully raise three foster chicks in Spain
Conservationists in the Spanish Basque Country have reported an unusual and successful breeding season after a pair of female Bonelli’s Eagles adopted and raised three young placed in their nest.
A pair of female Bonelli’s Eagles has successfully adopted and raised three chicks in northern Spain, in what conservationists have described as a remarkable example of the species’ parental behaviour.
The breeding event took place in the Basque Country, where wildlife authorities and conservation groups have been working to strengthen the regional population of this threatened raptor.
According to Ornithomedia, the two females occupied a territory together and accepted three young eagles that had been placed in their nest as part of a conservation programme. The chicks were subsequently fed and raised successfully by the pair.
Bonelli’s Eagle populations declined sharply across parts of western Europe during the twentieth century because of habitat loss, persecution, electrocution on power lines and reductions in prey populations. Conservation projects in Spain have included nest monitoring, supplementary feeding, reintroduction work and efforts to improve breeding success.
Although same-sex pairings are uncommon, they have occasionally been documented in birds, particularly among long-lived species with complex social and territorial behaviour. In this case, the two female eagles reportedly formed a stable pair bond and defended the territory together.
The adoption formed part of a wider management effort designed to improve survival rates for young Bonelli’s Eagles. By placing chicks into an occupied nest attended by experienced adult birds, conservationists hoped to increase the chances of the juveniles reaching independence.
The successful outcome demonstrated that the pair was capable of carrying out all the normal parental duties required to rear the young, including feeding, brooding and nest defence.
Bonelli’s Eagle is one of Europe’s rarest birds of prey and remains scarce across much of its range. Spain holds one of the continent’s most important remaining populations, making conservation work there particularly significant for the species’ future in Europe.
The unusual breeding success has attracted attention not only because of the same-sex pairing, but also because it highlights the adaptability of raptors and the potential value of carefully managed fostering programmes in conservation projects.
Researchers and conservationists involved in the work hope similar approaches could help support vulnerable eagle populations elsewhere where breeding opportunities are limited.
May 2026
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