The two extinctions of the Carolina parakeet

Abstract

Due to climate change and habitat conversion, estimates of the number of species extinctions over the next century are alarming. Coming up with solutions for conservation will require many different approaches, including exploring the extinction processes of recently extinct species. Given that parrots are the most threatened group of birds, information regarding parrot extinction is especially pressing. While most recent parrot extinctions have been island endemics, the Carolina parakeet (Conuropsis carolinensis) had an 18th-century range covering nearly half of the present-day United States, despite which, they went extinct in the 20th century. The major cause of their extinction remains unknown. As a first step to determining what caused their extinction, we used a newly published, extensive dataset of Carolina parakeet observations combined with a Bayesian extinction estimating model to determine the most likely date of their extinction. By considering each of the two subspecies independently, we found that they went extinct ~30 years apart: the western subspecies (C. c. ludovicianus) around 1914 and the eastern subspecies (C. c. carolinensis) either in the late 1930s or mid-1940s. Had we only considered all observations together, this pattern would have been obscured, missing a major clue to the Carolina parakeets extinction. Since the Carolina parakeet was a wide-ranging species that went extinct during a period of rapid agricultural and industrial expansion, conditions that mirror those presently occurring in many parts of the world where parrot diversity is highest, any lessons we can glean from their disappearance may be vital to modern parrot conservation efforts.