White-faced Storm Petrel

The White-faced Storm Petrel does not pose any identification problems thanks to the combination of the design of its head and, above all, its very light underside and its long thin legs that extend beyond the tail while in flight.
Seen from beneath, the bird is light, practically white, only the primaries and rectrices, of a medium grey, are not, but from a distance, the underside really looks white. The head is contrasted with a crown and post-ocular line that is dark, separated by a clear white eyebrow that reaches the forehead, which is also white.
The upper side appears dark, with very dark primaries and rectrices, coverts of a slightly lighter grey, as is the rump; one can distinguish a narrow white band formed by the tips of the large coverts. The tail is cut straight, sometimes very slightly forked.
The beak, black, is slender.
This White-faced Storm Petrel could be mistaken for the White-throated Storm Petrel (Nesofregetta fuliginosa) which is considerably larger and the Hornby's Storm Petrel (Oceanodroma hornbyi) which has the underside of the wings completely dark.