Birds, Bugs, and Agroforestry
January 1, 2008 by Gregory Gough
Scientists combined data from numerous studies, in both temperate and tropical climates, on the effect of birds on insects. The studies' findings were remarkably similar: when birds were excluded from trees (through the use of netting), insects, and insect damage to trees, increased.
The effects of bird predation were noticeable even in simplified forests, such as agroforests, where a canopy of trees provides shade for coffee or cacao shrubs below. Bird predation on insects reached its peak in the winter, when an influx of migratory birds augmented the predatory nature of the resident birds.
Not surprisingly, the more birds that are present, and the greater the variety of birds, the more bugs are eaten.
This article summarizes the information in this scientific paper:
Van Bael, Sunshine A., Philpott, Stacy M., Greenberg, Russell S., Bichier, Peter, Barber, Nicholas A., Mooney, Kailen A. and Gruner, Daniel S. 2008. Birds as predators in tropical agroforestry systems. Ecology, 89(4): 928–934