Wildlife Damage Management, Internet Center for

 

Date of this Version

October 2000

Abstract

In Dade County, Florida, the production of tropical fruit is a major component of the agricultural industry with total sales amounting to $73.5 million in the 1997-1998 season. Two types of fruit in particular, lychee (Litchi chinensis) and longan (Euphoria longana), are rapidly emerging in economic importance with a combined annual value of over $19 million. For many lychee and longan growers, bird damage is perceived to be a significant constraint to production, yet there is no published information on the extent of damage caused by birds. In 1999, we initiated research to identify the bird species responsible for longan damage, quantify the extent of bird damage, and estimate monetary losses. Estimates of fruit loss in 3 longan orchards ranged from 4% to 64% which resulted in losses of $536 to $ 18,182 per hectare. Common grackles (Quiscalus quiscula) were the most prevalent pest birds, but monk parakeets (Myiopsitta monachus) were equally if not more destructive, resulting in 30 times more damage at the orchard where they were present. In 2000, we expanded the study to include lychee. Estimates of bird damage to longan ranged from 1% to 28% ($259/ha to $17,623/ha) with the greatest damage occurring in the orchard subject to grackle and monk parakeet depredation. Bird damage to lychee was substantial (11%, $477/ha) in only lof 4 the groves studied. Monk parakeets were not observed to feed on lychee. We conclude that damage to longan and lychee by grackles is common but usually not great. In longan orchards frequented by monk parakeets, however, damage increases dramatically. Long-term bird management strategies should include exclusion with netting in high-damage areas as well as consideration of reduction in monk parakeet populations.

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