Monk Parakeets In The United States: Population Growth And Regional Patterns Of Distribution

Records from Christmas Bird Counts were summarized to assess population growth of the Monk Parakeet (Myiopsitta monachus) in the United States from 1975 to 1996. Population growth over this period fits an exponential model of population growth with a current annual rate of increase of 12.9% and a doubling time of 5.4 years. Since 1990, however, population growth on a national scale has slowed considerably, suggesting that the species may be approaching a carrying capacity. In contrast to the results across the entire United States, the population of Monk Parakeets in northeastern Illinois has dramatically increased in numbers within the last decade. In this region, the Hyde Park, Chicago population appears to be acting as a source from which other areas are colonized. The Monk Parakeet is known to have caused damage to fruit crops in Florida, and they can be a nuisance species to local utility companies when they build their nests on power transformers. Nevertheless, such damage is highly localized and, on a national scale, there is no evidence to date that Monk Parakeets should be considered a pest species and subject to widespread control. The initiation of detailed studies of a banded population of this species is recommended.