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The number of black-backed gulls (Larus dominicanus) between the Otaki and Ohau Rivers, on the southwest coast of the North Island, has more than doubled in the last 25 years. There was a significantly larger proportion of subadults in 1961 than now, indicating that the population may have been in a growth phase in the early 1960s. The number of red-billed gulls (L. novaehollandiae) was about one-third of the 1961 level; this coincides with a sharp fall in the number of red-billed gulls nesting on nearby Kapiti Island. Numbers of other coastal birds were recorded and are discussed.