Meeting Abstract
Animals must make escape decisions based on the perceived risk presented by potential predators. In populated environments flight initiation distance (FID) from approaching humans is often shorter, likely due to habituation to human presence. We asked whether birds are able to discriminate between human approaches in different contexts and adjust their FID accordingly. Penguin Island is a small island off the coast of Western Australia. Access to the island is common and frequent, with multiple daily ferry trips; however, human activity varies across three distinct environments: a boardwalk, beaches, and a native scrub wildlife sanctuary. We tested the FID of silver gulls (Chroicocephalus novaehollandiae) across each habitat, predicting the shortest FID on the boardwalk, where human approaches are frequent and follow a predictable path, intermediate FID on the beach, where human approaches are frequent but follow unpredictable paths, and longest FID in the scrub, where human approaches are infrequent and follow unpredictable paths. We found that FID was shortest on the boardwalk, but did not differ between the beach and scrub. In addition, distance from the boardwalk did not affect FID in the scrub. We suggest that silver gulls use human path predictability in specific contexts, rather than habituation to human presence alone, as a primary factor in making escape decisions.
