Enhancing ecosystem services in apple orchards.
This paper presents the results of a field study conducted in Spain, to evaluate the effectiveness of installing nest boxes for insectivorous birds in increasing pest control in apple orchards. Blue tits, great tits, and a few common redstarts occupied the nest boxes. When the birds started feeding nestlings, their ability to reduce pest numbers was estimated by counting the number of pecks on plasticine models of caterpillars of apple pest lepidopterans. The abundance of arthropods (including pests) on apple trees were also quantified and prey items brought back to the nestlings in the bird boxes were identified. The results showed that pest control improved in orchards where there were nest boxes compared to those without. In the orchards with nest boxes, there were higher rates of attacks on plasticine caterpillars, lower abundances of arthropods and, remarkably, lower probabilities of finding pests on apple trees.