Six captures of a dark-rumped, fork-tailed storm-petrel in the northeastern Atlantic

We report here the occurrence of at least six records since 1983 of dark-rumped and fork-tailed Storm-petrels. The first one was attributed to the Swinhoe's Storm-petrel Oceanodroma monorhis , a subspecies or a close relative of Leach's Storm-petrel O. leucorhoa , breeding in Japan. As it seemed unlikely that six birds from Japan would appear in the northeastern Atlantic nearly simultaneously, a closer examination of measurements and calls was performed. However, after a careful study of systematics within the Leach's Storm-petrel complex, it is concluded that the European birds are inseparable from monorhis , and it is suggested that a yet undiscovered colony may exist in the North Atlantic.