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The distribution and abundance of seabirds in eastern Cook Strait during autumn is described. Notes on identification and behaviour are also included. Three coastal currents of mixed subtropical and sub-antarctic origin intermingle in eastern Cook Strait. Seabird assemblages of this region are dominated in autumn by large numbers of non-breeding migratory shearwaters from northern New Zealand. These birds leave in early May and are replaced by subantarctic species. White-capped mollymawks, SaIvin’s mollymawks and giant petrels are numerous in early autumn prior to their dispersal into the eastern boundary currents. The seasonal variability of food for offal-feeding petrels is much less than for species which feed solely on pelagic organisms. This explains the rarity with which flesh-footed shearwaters, Cape pigeons, Westland black petrels and albatrosses are cast ashore, and limits the value of storm-killed records as indices of petrel abundance.