黑背白腹穴鳥 Pseudobulweria rostrata

Medium-sized seabird, mostly dark brown with a contrasting white belly. Look for the combination of very long narrow wings and a heavy bill. Flight style is typically rather relaxed with slow powerful wingbeats. Found over warm tropical waters, where it can be seen singly or in loose groups with other seabirds over productive feeding areas. Breeds on islands in the South Pacific.