Saving the Spanish imperial eagle was never going to be easy. This enormous bird, which once dominated the skies above Spain, Portugal, and northern Morocco, saw its numbers drop to just 380 breeding pairs in 2014, thanks to habitat loss, poaching, poisoning from farmers and hunters, and electrocution from power lines. Now, a new study highlights a potential way of restoring eagle populations to their former glory: dropping them into long-abandoned habitat.
One common approach for bringing threatened species back from the brink is to reintroduce them to the places they were last known to live. For example, the sea eagle in Scotland—which was hunted to extinction on the Isle of Skye in 1916—was successfully reintroduced in 1975 to Rùm Island near its last known breeding ground. But not all such efforts bear fruit: When scientists tried to release the same bird to its former range in western Ireland in 2007, the newcomers fell victim to the same poisoning that had done them in 107 years earlier.
“The tendency is to think that the last place that an animal was present is the best place for the species, but this isn't always the case,” says Virginia Morandini, a biologist with the Spanish National Research Council’s Doñana Biological Station near Seville.