Black-vented Shearwater is much smaller with a faster wingbeat. Buller's Shearwater is much whiter underneath with a different upperwing pattern. Rare Streaked Shearwater is paler below with a different head pattern. At a distance, Sooty Shearwaters are smaller with faster wingbeats. Immature gulls are superficially similar but can be separated at great distances by their different flight styles. Shearwaters fly closer to the surface of the water, often disappearing behind swells, alternating flaps with long glides on downcurved wings.