Evaluating how the group size of domestic, invasive dogs affect coastal wildlife responses: The case of flight-initiation distance (fid) of birds on Southern Australian beaches

© Springer International Publishing AG, part of Springer Nature 2019. Accompanied, domestic dogs frequently disturb birds on coasts, and meet the ecological definition of invasive species. Dogs occur most commonly singly or in ‘packs’ of two dogs. We examine whether group size (one versus two leashed dogs) influenced Flight-initiation Distance (FID), a measure of wariness towards potential predators, of birds on southern Australian beaches. We report 303 FIDs from 16 species, of which seven species had sufficient data to compare responses between one and two dog approaches. None of the seven focal species varied their FID or escape modality (walk/run versus fly) with one versus two dogs approaching. Birds do not apparently judge risk associated with dogs in relation to ‘pack’ size. Regulations which reduce the number of dogs walked are therefore unlikely to reduce disturbance of coastal birds. Further studies, using unleashed dogs, and dogs which bark, may evoke greater responsiveness than reported here and may reveal indirect effects of dog group size.