A long-winged, black-and-white bird that is most often found far out at sea, coming to land only to breed on remote cliffs from November into May. Adults visit the nest sites only at night, when it is possible to hear this species vocalizing. The rather similar Bermuda Petrel lacks this species’ white collar and white rump. Black-capped Petrels also have a darker headed or “cowled” appearance than Bermuda Petrels. Calls at nesting areas include a drawn out “awwwww” that often grows louder towards the end and is usually given in series, sometimes with a squeaky hiccuplike terminal note that has an oddly donkey-like quality. Also gives a puppy-like yelp.