Chile investigates unexplained Andean condor deaths

Health authorities are trying to find out what poisoned at least 20 condors in the Andes mountain range between Chile and Argentina.

The huge endangered birds, with a wingspan of up to 3m, were found near the town of Los Andes, about 80km east of the Chilean capital, Santiago.

The authorities say two birds died, but 18 are recovering at a clinic.

They suspect the damage may have been caused by eating carcasses of poisoned cattle, fox or puma.

Witnesses alerted the authorities on Sunday after seeing the condors, known for their effortless gliding at high altitudes, flying low and crashing into rocks.

'Phosphorous compounds'

Once on the ground, they were not able to take off again and walked apparently dizzily and foaming from the beak, authorities say.

The birds were taken to a veterinary facility and are said to be recovering

Most of the sick Andean condors were found on Sunday

Two dead birds and the corpses of two foxes were also found near Los Andes

The Chilean veterinaries of the town of Los Andes are treating the huge birds

The Andean condors will be released when they have recovered completely

Two of the birds were reportedly found dead, as well as two foxes.

"[The poisoning] seems to have been caused by the ingestion of an ill animal or one that ate another being with some phosphorate compound," the regional director of the Chilean Farming and Cattle Service, Pablo Vergara, told the Argentine newspaper Clarin.

The chemical compound can be found in herbicides and poison used to kill animals considered to be pests.

The poisoned condors were taken to a veterinary clinic, given an antidote and are said to be recovering.

The possibility of finding more animals with the same symptoms has not been ruled out.

The Andean condor is one of the world's biggest bird species and is considered a symbol of the region.

Scientists estimate less than 10,000 condors live in the wild.