The Thick-billed Parrot (Rhynchopsitta pachyrhyncha)

Abstract

More than one-quarter of the world’s parrot species are threatened with extinction. Habitat and nest site destruction, hunting, exploitation for the black market pet trade, and introduced species placed pressure on these fragile populations. 1 With the sole exception of the extinct Carolina parakeet (Conurupsis carolinensis), the thick-billed parrot ( Rhynchopsitta pachyrhyncha pachyrhyncha ) is the only parrot species whose natural distribution once included parts of the continental United States. The last free-living Carolina parakeet was collected in 1904 near Lake Okeechobee, Florida, USA. The species went extinct in 1918 when a solitary captive bird died at the Cincinnati Zoo. This small psittacine, which once ranged from Virginia to Florida in the United States, was attracted to the cypress and sycamore trees that grew along rivers and swamps. The population began its noticeable decline in 1832 as human settlement increased and moved inland from the east. Settlers hunted this bird for food and trade, persecuted it to protect their crops, and destroyed its primary habitat. 2 Thick-billed parrots ranged from the southwestern United States to northern Mexico until the 1930s. Their current range is limited to 170 000 km 2 in Mexico’s Sierra Madre Occidental. 2 Habitat destruction along with hunting pressures caused the extirpation of thick-billed parrots from southeastern Arizona and southwestern New Mexico in the United States. Current populations continue to decline because of deforestation and trapping for the pet bird trade. Less than 1% of the old-growth forest that once covered Mexico’s Sierra Madre Occidental remains. 2,3 Thick-billed parrots inhabit high-ele