Scientists in Puerto Rico have reintroduced 15 endangered Puerto Rican parrots into the wild as part of a conservation program.

Natural Resources Secretary Carmen Guerrero says the birds were released early Wednesday in a forest near Puerto Rico's north coast. It is the ninth release at the Rio Abajo Nature Preserve since 2006.

Guerrero said another 204 parrots remain at the preserve, while an estimated 57 to 108 parrots are believed to live in the wild nearby.

The Natural Resources Department also manages another breeding center at El Yunque tropical rain forest in northeast Puerto Rico.

The birds are Puerto Rico's only remaining native parrot. Scientists estimate that as many as 1 million existed in pre-colonial times, with numbers reaching a low of 13 in 1975.