Direct losses of birds to pesticides - beginnings of a quantification
This article is part of a larger document. View the larger document here.Abstract
Recent analyses and modeling of avian pesticide field studies have led to the conclusion that bird kills are regular and frequent in insecticide-treated fields. Unfortunately, data are seldom adequate to quantify this mortality. Also, mortality is expected to be highly variable in response to varying bird presence in and around treated fields. Studies reporting kills of birds in cornfields treated with granular formulations of carbofuran provide a good example of the types of calculations that are needed to estimate direct bird losses in farm fields. Several studies provide the means to correct carcass counts for search efficiency and scavenging. Based on typical Midwest cornfields, use of granular carbofuran resulted in an estimated annual mortality rate of 3.0 to 16 songbirds per ha of treated field, the higher number corresponding to better field edge habitat. Much larger kills also occurred where fields bordered non-crop habitat more suitable for birds. At the peak of its popularity in the United States, this single product was conservatively giving rise to an estimated annual loss of 17- 91 million birds in cornfields alone. Granular carbofuran formulations continue to be sold and used in most Latin American countries on a wide variety of crops.