Land converted to coffee agriculture occupies >5 million hectares of what was once prime overwintering natural habitat in the American Neotropics for migrating birds. When tree canopy is retained or restored (i.e. shade-grown), coffee farms can serve as habitat refuge for wildlife. Yet few studies have examined whether canopy tree identity impacts habitat quality for biodiversity. Specifically, whether or not certain tree species are disproportionately important for foraging insectivorous birds remains unclear. In this study, we quantified bird foraging activity on 22 tree species in two Latin American Bird Friendly© coffee farms. Specifically, we conducted timed observations on focal trees to determine 1) tree preferences, 2) foraging bird abundance, 3) foraging time, and 4) species richness of birds using each canopy tree species. We found that birds did not forage randomly, and instead exhibited preferences for particular native tree species. Nitrogen-fixing Fabaceae were consistently used more frequently, supported more resident and migratory birds for longer periods of time, and supported more bird species than trees in other families. We posit that the potential mechanism contributing to tree preferences is the increase in insect abundance and diversity that provide high quality food for insectivores but do not present pest problems for coffee. Thus, tree species that support insects may provide multiple benefits for farmers in the form of bottom-up soil fertilization and top-down pest control. This study provides evidence that agroforestry land can be improved for birds of conservation concern by prioritizing canopy tree species that help birds and farm productivity.
Foraging bird abundance on canopy trees within shade-coffee farms
Abundance of foraging birds of each species for each observation period. country: country data was collected in (Nicaragua or Colombia); year: year data was collected (2015 or 2016); observer: observer initials; date_format: date of observation; juldate: julian calendar date; observation_num: observation number; treeID_format: individual code to identify trees; observationID: unique identifier; treesp: tree species common name (see paper for species names); time_format: time of observation; bird_sp: bird species common name (Colombia) or code (Nicaragua); num_birds: count of individuals; migratory_insectivore: binary dummy variable for primarily insectivorous migratory species; notes: miscellaneous notes; canopy_volume: canopy volume (meters cubed); scale_volume: scaled canopy volume with mean zero
bothcountries_data_format_19feb2019_abundance_format.csv
bothcountries_data_format_19feb2019_foragingtime_format
Foraging times of individual birds on trees. country: country data was collected in (Nicaragua or Colombia); year: year data was collected (2015 or 2016); treesp: common name of tree species (see paper for species names); treeID: unique identifier for individual focal trees; bird.sp: common name (Colombia) or code (Nicaragua) for bird species observed); migratory_insectivore: binary dummy variable indicating if bird species was a primarily insectivorous migratory bird; total_sec: total number of seconds observed foraging in the focal tree; vol: canopy volume of the focal tree (meters cubed); prop_sec: proportion of the total observation period (600 seconds) that the individual bird was observed foraging; scale_vol: scaled canopy volume with mean zero.
bothcountries_species_richness_longformat
Number of individuals for each bird species on all trees observed including zeros. country: country tree was observed in (Nicaragua or Colombia); year: year of observation (2016); treesp: common name of tree species observed (see paper for species names); bird_sp: common name (Colombia) or code (Nicaragua) for each bird species observed; count: number of individuals observed (including zeros if never observed foraging in a tree species).