We are grateful to the staff of Orkney Ferries for allowing access to vessels to carry out surveys. 

The work was funded by the Contract Research Fund, administered by the Scottish Government Rural and Environment Science and Analytical Services.

Capsule: Recording of behavioural responses to ferry traffic for eleven target species showed that Red-throated Diver Gavia stellata, Slavonian Grebe Podiceps auratus and Black-throated Diver Gavia arctica were most likely to react to passing vessels.

Aim: To provide information on how responses to marine traffic vary between waterbird species to inform marine spatial planning and environmental impact assessments in the near-shore environment.

Methods: We recorded behavioural responses to ferry traffic for eleven target species in near-shore waters: Eider Somateria mollissima, Goldeneye Bucephala clangula, Long-tailed Duck Clangula hyemalis, Velvet Scoter Melanitta fusca, Red-breasted Merganser Mergus serrator, Black-throated Diver, Great Northern Diver Gavia immer, Red-throated Diver, Shag Phalacrocorax aristotelis Slavonian Grebe and Black Guillemot Cepphus grylle. Responses were analysed using generalized linear models.

Results: Red-throated Diver, Black-throated Diver, Slavonian Grebe were the most likely species to exhibit a response to passing vessels. While Red-throated Divers were highly likely to flush, Black-throated and Great Northern Divers rarely took flight, instead favouring swim or dive responses.

Conclusions: This research provides comparative evidence on behavioural responses of waterbirds to marine traffic. The results support previous studies which highlighted the high sensitivity of diver species to disturbance and provide new evidence that Slavonian Grebe is also a high sensitivity species.