SAN DIEGO -- A golden eagle rescued on the Viejas Indian Reservation was being treated Tuesday for kidney problems at a La Mesa veterinary clinic.

A reservation security guard found the rare bird on Saturday lying on the ground and unable to fly, The San Diego Union-Tribune reported.

Once healthy enough, the six-pound eagle with a five- to six-foot wingspan is expected to be released back on the reservation, according to the newspaper.

The golden eagle is not endangered but experts estimate there are only about 50 pairs left in San Diego County.

Veterinarian Todd Cecil of the Pet Emergency and Specialty Center is treating the injured bird and told the Union-Tribune that the bird may have collapsed after eating something poisonous.