LA PAZ -- The mysterious deaths of 35 giant condors, one of the world's largest flying birds, are being probed in Bolivia, where they are often found in the Andean regions.

The corpses of the condors, a goat and two dogs were found an hour and a half from the Bolivian city of Tarija, on the border with Argentina.

The Andean condor, which can grow as long as 4 feet (1.22 m) with a huge wingspan of 10.5 feet, is "vulnerable," according to the International Union for Conservation of Nature. There are some 6,700 of the species worldwide but numbers are falling, hurt by issues from lead poisoning, to habitat loss and hunting

California Condors are even worse off, designated as critically endangered.

"It is very rare to have animals like a goat and three dogs dead in the same the place where the 35 condors are," said Magin Herrera Lopez, Bolivia's deputy minister of environment. They might have died about 10 days ago from poisoning, he added.

Authorities suspect the goat meat might have been poisoned and left for wild cats to eat, but it was instead consumed by the dogs and condors. Tarija's governor has ordered the testing of samples from the birds.

Among the dead condors were 17 adult females and 18 adult males, said Juan de Dios Garay, a biologist from NGO Nativa Bolivia. Many chicks and un-hatched eggs might have been abandoned because of the deaths, he added.

"This worries us a lot," said Herrera Lopez, the government minister.