How does the flight of southern storm petrels differ from that of northern storm petrels?

The flight and foraging behaviors of storm petrels differ significantly between the two primary structural groups:

• Southern species: These birds typically possess shorter wings and longer legs. When foraging, they patter over the surface of the water, creating a "walking" motion as they pick up minute marine organisms.1
• Northern species: These birds generally have longer wings and shorter legs. Their foraging flight is characterized by swooping over the water in a manner similar to tiny terns, occasionally alighting on the surface.1