Spain calls on 'electric sheepdogs' to protect rare imperial eagle

Spanish scientists have launched an ambitious plan to halt the disappearance of the endangered Spanish imperial eagle, by teaching the birds not to electrocute themselves.

This magnificent bird of prey, which lives only in Spain and Portugal, almost died out in the 1960s. Despite efforts to save them, their chances of survival remain precarious. Fewer than 220 birds are reckoned to inhabit the Iberian peninsula, mostly around Andalusia's Coto Doñana national park where they are the main attraction.

But they face danger of electrocution from high-tension power cables that criss-cross their flight path. This accounts for 60 per cent of deaths of imperial eagles in their first year of life. The birds have also fallen victim to poison set by farmers to combat foxes, and the drastic fall in numbers of rabbits, their main prey.

Biologists at Spain's principal scientific investigation centre, CSIC, are pioneering a system of "electric sheepdogs" designed to teach eagle chicks to avoid the deadly cables. Posts carrying mild electric current are placed near their nests so that chicks, when they land on them, receive a "harmless but disagreeable" shock intended to warn them off the real thing. "We expect that they will end up associating this shock with electric cables and posts in general, and stop landing on them," says Miguel Ferrer, whose research team has fought for years to save Aquila adalberti.

"We know that what they learn during their early youth marks their behaviour through their adult life. Their whole life is conditioned by this stage when they learn to fly, hunt, conquer a territory and seek a mate," Dr Ferrer said. "For the first time we will be able to establish if it's possible to induce cultural changes in the behaviour of threatened species to teach them to avoid potential dangers.

"If they learn, we could probably reduce deaths by electrocution to zero."

Naturalists have worked with the electric companies to install gadgets to discourage birds from landing on cables or crashing into pylons. Spain claims to be the only European country where electric cables are installed with legal regulations that seek to avoid harming wild birds.

A further experiment provides special protection to female chicks. Male eagles significantly outnumber females, a natural consequence of the fact that the male is smaller than the female. Imperial eagles mate for life, so unless the ratio between sexes is evened up, they will produce fewer eggs, and eventually die out.

Scientists remove female chicks from nests in areas where chicks run a high risk of death, then raise them in "semi-liberty", fed by researchers, until they are freed. Fifteen females are expected to be reintroduced into the wild within three years.