Conservation Biological Control (CBC) is defined as the modification of the environment to protect or enhance native predator populations to reduce the impact of pest species. A common CBC practice is the installation of artificial nest boxes and roosting sites for falcons, such as the American kestrel, to reduce agricultural pests. Kestrels are widespread, generalist predators that hunt in open habitats, including human-dominated landscapes.
Kestrels using orchard nest boxes in the fruit-growing region of northwestern Michigan eat insects, mammals, and fruit-eating birds. To determine whether kestrel activity associated with nest boxes and artificial perches increases predation, as well as perceived predation risks to fruit-eating birds, NWRC and Michigan State University scientists surveyed fruit-eating bird abundances in cherry orchards with and without kestrel nest boxes. They also analyzed the costs and benefits of installing nest boxes and used a regional economic model to estimate the economic impacts of increased cherry production in Michigan.
Results showed that fruit-eating bird counts were significantly lower at orchards with active kestrel nest boxes. Furthermore, benefit-cost ratios for kestrel nest boxes indicated that for every dollar spent on nest boxes, $84 to $357 of sweet cherries would be saved from fruit-eating birds. Regional economic modelling predicted that increased sweet cherry production from reduced bird damage would result in 46–50 jobs created and $2.2 million to $2.4 million in increased income for the state of Michigan over a 5-year period.
For more information, please contact NWRC@usda.gov.