SummaryBretagnolle, V.&Thomas, T. (1990). Seabird distribution between Tasmania and Adélie Land (Antarctica), and comparison with nearby Antarctic sectors.Emu90, 97–107.Qualitative and quantitative observations of sea birds were made during crossings between Tasmania and Adélie Land, Antarctica, in December of 1980, 1983 and 1984, and in February 1986. From analysis of the latitudinal distribution of the 30 species encountered, we have distinguished four different groups. The addition of our data to those available in neighbouring regions (southern Indian and southern Pacific Oceans) has helped to clarify longitudinal distributions of these species. Strictly Antarctic birds show the most homogeneous distribution. A synthesis of all data relating to movements of Mottled Petrel during the austral summer showed that the distribution of this species does not overlap with any of its closest relations among the gadfly petrels. We suggest the Mottled Petrel may be monopolising a productive area in the absence of interspecific competition. Several other species observed (Wandering Albatross, Black-browed Albatross, Cape Pigeon, etc.) show a discontinuous distribution in latitude and in longitude, which may indicate the occurrence of two groups with different geographical origins.