Habitat selection, habitat use, and home ranges of black-throated blue warblers on Jamaican coffee farms: implications for an ecosystem service

Ecosystem services provided by mobile organisms are influenced by the availability of the habitats those organisms select. On Jamaica's coffee farms, birds serve as agents of biological control of the coffee berry borer (Hypothenemus hampei), coffee's most devastating pest worldwide. The black-throated blue warbler (Setophaga caerulescens) is likely the foremost avian predator of coffee berry borer in Jamaica. Using radio telemetry I investigated habitat selection, habitat use, and home range size of black-throated blue warblers on two coffee farms with different vegetative complexity in western Jamaica. I developed individual-optimized and population-optimized models of habitat selection using four variables describing coffee habitat. Despite considerable variation in habitat selection among individual birds, population-based models demonstrated that birds selected home ranges in areas of high canopy cover and coffee crop cover, and at intermediate distances from uncultivated habitat on both farms. Within home ranges, birds exhibited weak selection for increasing canopy cover. Home range size was correlated with the proportion of the locations in coffee habitat and the availability of canopy cover and noncultivated habitat within the home range. However, the direction of several of these relationships differed between farms. Birds at the farm with higher vegetation complexity spent, on average, 63% more time in coffee habitat and 60% more time in the coffee crop layer where birds are most likely to encounter the coffee berry borer. I conclude that substantial differences in physiognomy between farms translated into the pattern of differential use of the coffee farm habitat relative to peripheral habitats. These results suggest that managing for the habitat attributes selected by warblers in this study can have measurable impacts on bird use of coffee farms in Jamaica with potential implications for bird-provisioned ecosystem services.