Birds Keep Coffee Farms Pest-free

January 1, 2000 by Gregory Gough

Scientists wondered how important birds are for controlling insect populations in tropical forests, so they set up netted exclosures to keep birds off coffee shrubs in Guatemalan coffee plantations and compared them to un-netted areas.

brown bird sitting on branch with insect in beak

Large insects were 64 to 80 percent more common inside the exclosures, indicating that the birds did an excellent job of controlling their populations outside the exclosures. Small insects were equally common inside and outside the exclosures.

The coffee plantations were either shaded by a canopy of trees or open to the sun. Sun plantations had 10 times fewer insects.

Although there are not many insects that forage on coffee shrubs it is likely that the birds in a shade coffee plantation do an excellent job of keeping them under control.

This article summarizes the information in this scientific paper:

Greenberg, Russell S., Bichier, Peter, Angon, A. C., MacVean, C., Perez, R. and Cano, E. 2000. The impact of avian insectivores on arthropods and leaf damage in some Guatemalan coffee plantations. Ecology, 81: 1750-1755.

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