Snail kite (Rostrhamus sociabilis) feeding efficiency on pest channeled apple snails (Pomacea canaliculata) increases in rice fields with ‘natural’ and artificial perches

Biological control of invasive pests poses significant challenges. Predators need to be capable of exerting meaningful suppression of invasive prey populations, yet even highly specialized predators may fail to do so if habitat structure limits their foraging success. The channeled apple snail ( Pomacea canaliculata ) is now established as a major agricultural pest across rice-growing regions worldwide and predators specialized in these snails could be suitable candidates for biological control. The snail kite ( Rostrhamus sociabilis ) feeds almost exclusively on snails of the genus Pomacea ; nevertheless, its efficiency as a predator of this recent invasive pest has not been thoroughly evaluated, particularly with respect to how habitat structure affects its predation success in rice systems. We conducted a study in rice fields of Daule, Ecuador, comparing snail kite foraging success in plots with natural perches, artificial perches, and no perches. We quantified snail consumption through monthly counts of empty snail shells and direct behavioral observations of foraging kites. We found that placing artificial perches in plots dramatically increased snail predation intensity. Capture rates were significantly higher in plots with natural (~ 6 times more) and artificial perches (~ 5 times more) compared to plots without perches. Kites in plots with natural and artificial perches exhibit shorter prey searching times compared with plots with no perches. Snails consumed at artificial perch plots were significantly larger than snails in plots with natural perches, suggesting that artificial perches could increase the removal of reproductively active females. Our findings suggest that placing artificial perches enhances the predation of invasive snails by snail kites in rice systems. Plots without perches, in contrast, can become pest refuges that allow snail populations to persist with minimal predation pressure. Artificial perches could contribute to reducing agrochemical dependence and supporting a more sustainable rice production while promoting the conservation of this specialized raptor.