VARIATIONS IN THE DISTRIBUTIONS OF MARINE BIRDS WITH WATER MASS IN THE NORTHERN BERING SEA

We examined the pelagic distributions of 12 species of northern Bering Sea birds with respect to the water masses in which they were observed during the summers of 1984, 1985 and 1986. Despite the prediction of earlier work that differences in community structure are unlikely to occur at small spatial scales, we found significant habitat preferences for all but one of the species studied. We suggest that the strength of the gradient between habitat types is the cause of this discrepancy, and that boundary conditions should also be considered when discussing the influence of spatial scales on community processes.