SAN DIEGO - U.S. researchers are launching studies on Mexico's red crowned parrot - a species that has been adapting so well to living in cities in California and Texas after escaping from the pet trade that the population may now rival that in its native country.

The research comes amid debate over whether some of the birds flew across the border into Texas and should be listed under the Endangered Species Act.

Parrots in U.S. urban areas are just starting to draw attention from scientists because of their intelligence, resourcefulness and ability to adapt.

There's also a growing realization that the city dwellers may offer a population that could help save certain species from extinction.