Proceedings of the Vertebrate Pest Conference
Rose-ringed Parakeets in California: Established Populations and Potentially a Serious Agricultural Threat
- Author(s): Shiels, Aaron B.
- Klug, Page E.
- Kluever, Bryan M.
- Siers, Shane R.
- et al.
The rose-ringed parakeet has been introduced to >40 countries, gaining its status as the most widely introduced parrot in the world. Although regarded as a strikingly beautiful bird by many people, this species is a severe agricultural pest that establishes and experiences a lag time prior to exponential population growth. In addition to agricultural damage, these birds cause noise and fecal pollution, aggregate in large night roosts near human structures, may be involved in disease transfer, and, in some cases, they may help spread invasive plants. In the U.S., rose-ringed parakeets have been reported in several southern states, but established populations are in Hawaii, Florida, and California. Escapees from the pet trade probably account for most introductions, and parakeets have been reported occurring in California as early as 1956. The estimated population in Bakersfield was 3,000 birds in 2012, and additional smaller populations have been reported in San Diego, Anaheim, Santa Cruz, Malibu, and Pasadena. Much of California, excluding expansive natural areas unoccupied by humans, is potentially at risk of rose-ringed parakeet colonization, and this species represents a conceivably important threat to California agriculture. Rose-ringed parakeets are known to consume and damage crops such as rice, sunflower, safflower, rapeseed, and citrus in native India; almonds in rural Italy; and corn and fleshy fruit (e.g., guava, mangos, lychee, papaya) in Hawaii. In 1975, the California Department of Agriculture estimated that the potential crop losses due to a well-established rose-ringed parakeet population could reach US$735,000 annually, a value that resulted from an estimate of their damaging 0.1% of crops grown in the area. Rose-ringed parakeets are a serious agricultural pest in several areas outside of California, and all areas where they thrive are in human-altered landscapes. An update is needed on this species’ distribution, population changes, and impacts to agriculture within California. Furthermore, we recommend establishing an annual monitoring plan of the established California populations, as well as efforts to prevent their spread and reduce their threat to California agriculture.