Associations between seabirds and cetaceans: a review

(1) Seabird-cetacean associations involve many genera.
(2) Some seabirds/cetaceans associate with more species than others, e.g. minke and pilot whales, Common dolphins and porpoises amongst cetaceans, and gannet & kittiwake amongst seabirds. Killer whale, sperm whale, shag and cormorant have not been recorded in associations, in the N.E. Atlantic.
(3) All observed associations would be predicted on the basis of the diets of the associated species.
(4) Most associations are probably opportunistic or incidental, as a result of concentration of shared prey.
(5) Some species, however, may associate more regularly, e.g. minke & pilot whales, Common dolphin and porpoise amongst cetaceans and gannet amongst seabirds. It is not possible to say which derives benefit from the association, but on theoretical grounds it is most likely to be the seabird.
(6) Minke and pilot whales may drive towards the surface food normally out of reach of seabirds, particularly Procellariformes. Common dolphins feed by herding fast-moving fish shoals into tight groups which will be a more concentrated food source for diving sea-birds, such as gannets, and make food more accessible to other species. Porpoises may achieve the same result with inshore shoals of sprats and sand eels, particularly for auks and kittiwakes, and terns.