The daily life of a hummingbird: High-throughput tracking shows a spectrum of feeding and movement strategies

Abstract

Most pollinators, with their small size and flight ability, are a challenge to study in the wild, yet their behavior is essential for understanding patterns of biodiversity. For example, hummingbirds play a significant role in their ecosystems--their movements from plant to plant across landscapes ultimately determines their potential as pollinators, but these behaviors are poorly understood. Two movement types are most commonly assumed in hummingbirds: territoriality and traplining, the latter strategy involving repeated and predictable visitation to dispersed feeding locations. However, direct evidence for traplining mostly comes from captive birds. In this study, we collected data from white-necked jacobin hummingbirds (Florisuga mellivora) that were implanted with tiny radio-frequency identification (RFID) tags, tracking their movement among a network of 20 tag-detecting feeders spread across the town of Gamboa, Panama, for 99 days. The resulting data cover over 47,000 feeder visits from 97 freely moving birds. Overall, we found scant evidence for traplining as a consistent strategy in this species. Instead, we identify three clusters of daily movement types, two of which are difficult to characterize as either territoriality or traplining. Our findings demonstrate that a diversity of movement strategies can be found within a single hummingbird species and even within individuals, and that many questions remain about the movement of these ecologically key vertebrates. To better understand the ecological role of hummingbirds, the description of a greater diversity of movement types beyond territoriality and traplining is likely to be necessary.