Research: migratory birds provide pest control, increase profit, in Jamaican coffee farms

Ecological and economic services provided by birds on Jamaican Blue Mountain coffee farms. 2008. Kellermann, J. L., M. D. Johnson, A. M. Stercho, and S. C. Hackett. Conservation Biology 22:1177-1185.

There have been several good papers published lately on coffee farming that I will be summarizing, but this was the most interesting to me, as I have seen the data presented at recent ornithological conferences.

This study looked at the benefits birds provide by preying on coffee berry borers at four coffee farms in Jamaica's Blue Mountain region: Clifton Mount, Wallenford, McGraham, and Rowan's Royale. Rowan's Royale is the only certified organic coffee farm in Jamaica. All others used the pesticide endosulfan four months before this study began. To see if birds were eating coffee berry borers, the authors excluded birds from some coffee plants to look at the rate birds were preying upon coffee berry borers.

Coffee trees in which birds had no access had higher rates of borer infestation and greater damage. Unprotected trees had rates of infestation that were up to 14% lower, and the declines were determined to be due to birds preying on the borers.

Seventeen bird species preyed on coffee borer beetles; eleven were North American migrants wintering in Jamaica. The decline of the borer infestations on coffee trees accessible to birds coincided with the arrival of migrant birds to the island. Three migrant species did most of the work: Black-throated Blue Warbler, American Redstart, and Prairie Warbler (right).

The authors calculated that the value of pest control provided by birds (via increased yield) to farmers averaged US$75 per ha of coffee, not a small sum considering there are 10,000 ha of coffee in Jamaica and the per capita gross income in the country is US$3400. This figure did not include any additional economic benefits such as reduction of other pests, the potential for savings in pesticide reduction, or additional environmental benefits of not using highly toxic endosulfan.

One important component to this study was the finding that these bird species increased with close proximity to native forest patches, and declined steeply on coffee plots that were further than 40 to 50 meters from a habitat patch. In order for farmers to receive these ecological services and economic benefits from the birds, they need to provide habitat for them! Preserving native forest is a win-win situation for the farmers and the birds.

Black-throated Blue Warbler photo by yours truly; American Redstart by my talented friend Steve Hamilton; Prairie Warbler by Scott A. Young.

J. L. Kellerman, M. D. Johnson, A. M. Stercho, S. C. Hackett. (2008). Ecological and economic services provided by birds on Jamaican Blue Mountain coffee farms. Conservation Biology, 22 (5), 1177-1185 DOI: 10.1111/j.1523-1739.2008.00968.x