Data for: Combining radio-telemetry and radar measurements to test optimal foraging in an aerial insectivore bird

Optimal foraging theory posits that foragers adjust their movements based
on prey abundance to optimize food intake. While extensively studied in
terrestrial and marine environments, aerial foraging has remained
relatively unexplored due to technological limitations. This study,
uniquely combining BirdScan-MR1 radar and the ATLAS biotelemetry system,
investigates the foraging dynamics of Little Swifts (Apus affinis) in
response to insect movements over Israel's Hula Valley. Insect
Movement Traffic Rate (MoTR) substantially varied across days, strongly
influencing swift movement. On days with high MoTR, swifts exhibited
reduced flight distance, increased colony visit rate, and earlier arrivals
at the breeding colony, reflecting a dynamic response to prey
availability. However, no significant effects were observed in total
foraging duration, flight speed, or daily route length. Notably, as insect
abundance increased, inter-individual distances decreased. These findings
suggest that Little Swifts optimize their foraging behavior in relation to
aerial insect abundance, likely influencing reproductive success and
population dynamics. The integration of radar technology and biotelemetry
systems provides a unique perspective on the interactions between aerial
insectivores and their prey, contributing to a comprehensive understanding
of optimal foraging strategies in diverse environments.