It is dark overall, with white on the rump and center of the belly and a small pale area under the wing. While feeding, it patters across the water with its wings held upright.
The plumage is mostly black, with white on the back and center of the belly and a small pale area under the wing. Its long legs extend beyond the tail in flight.
While feeding, it patters across the water with its feet and holds its wings upright. Its flight is erratic, with short, quick glides. The report describes coastal rocky islets as breeding habitat and the Humboldt Current offshore as feeding habitat.
An extinction-risk assessment has not been added yet.