Escape Flight Durations in Migratory Shorebirds: Insights from an Observational Study

Intertidal flats are critical habitats for migratory shorebirds. However, human activities such as fisheries and recreation frequently disturb shorebirds, triggering escape flights, defined as immediate flights to escape a perceived stimulus, that disrupt their normal activities on tidal flats, such as foraging and resting. We investigated the relationship of escape flight duration to humans approaching shorebirds from beyond their flight initiation distance. An observational study was conducted on an intertidal sandflat subject to frequent public use and unrestricted access, where data were collected on shorebird escape flight duration, flock size, visitor numbers, and environmental variables. Using a mixed model approach, flight duration was found to be positively correlated with species body size, flock size, and number of approaching humans. These findings indicate that escape flight duration is a multivariate response, which tends to increase when the number of approaching humans is higher, shorebird flock size is larger, and shorebirds belong to larger-bodied species. In order to minimize cumulative energetic costs of shorebirds due to prolonged escape flights, conservation strategies should prioritize maintaining extensive undisturbed tidal flats, restricting access to areas regularly used by shorebird flocks and regulating visitor numbers to safeguard foraging opportunities for shorebirds during low tide.