Bermuda Petrel (Pterodroma cahow) [XC738388]
by id from St.George's, St. George's Parish, United Kingdom (duet)
Subspecies
Sometimes treated as subspecies of Black-capped Petrel (Pterodroma hasitata). May be conspecific with Cape Verde Petrel (Pterodroma feae), and individual of latter recently captured in Azores could be link. Also linked to Zino's Petrel (Pterodroma madeira) on grounds of shared feather louse.
No subspecies.
Similar Species
Black-capped Petrel (Pterodroma hasitata) which is larger with white hindneck and more extensive white rump, but sometimes separation at sea may be impossible. Great Shearwater (Ardenna gravis) which is larger, darker and less contrasting above, lacks black edge to underwing and has slower wing-beats and less erratic flight.
References
See References.
BirdLife International Species Factsheet