Gallant geese, fearful flocks? Flock size and heterospecifics alter the escape behaviour of an invasive goose

Abstract

While escape responses are shown to differ in areas with varying levels of human disturbance, it is not known to what extent these reactions depend on the composition of local species assemblages. We investigated variation in three flight response metrics for the invasive Canada Goose (Branta canadensis) in Belgium in three locations with different human accessibility. Results indicate that heterospecific birds and flock size affected flight initiation distances of the Canada Goose, but that these effects are location-specific. Escape responses were most pronounced in the nature reserve with the lowest human accessibility, and highly reduced in the recreational park. This study illustrates that, when buffer zones are being developed, generalising escape behaviour of birds may lead to potentially dangerous overestimations of their tolerance to human disturbance.