The Audubon’s Shearwater, (Puffinus lherminieri) also known as Tropical Shearwater is a common seabird of the tropics from the family Procellariidae. Audubon’s Shearwater is a medium sized sea bird commonly seen from the yachts around the Galapagos islands.
Audubon’s shearwater has a worldwide distribution, with populations in addition to the Galapagos in the western and central Pacific, the Philippine Sea, the Indian Ocean and the Caribbean (although it is no longer present in Bermuda). The Galapagos population is considered to be an endemic subspecies.
The adult shearwaters are not thought to wander or undertake great migrations like other members of the genus Puffinus, although young birds do so before breeding. This sea bird nests in small burrows and crevices in rocks. Both parents share the responsibility of incubating the single egg, taking turns between 2 to 10 days each. The egg takes about 50 days to hatch and another 70 days to rear to fledging. Once fledged, a chick will take 8 years to reach breeding age. Like other shearwaters they are long lived birds.
The Audubon’s Shearwater can reach 30 centimetres. (12 inches) long and weigh up to 170 grams, about half the size of the Greater Shearwater. The upperparts and the undersides of the tail and flight feathers are blackish-brown and the rest of the underparts, cheeks and throat are white. It can be confused with the Manx Shearwater which has white undertail covers.
They feed on small planktonic crustaceans and fish larvae, which they take from the surface, and on small fish, and squid, which they catch by plunge diving to depths of about six feet. It is not uncommon to see them in fishing in large flocks, or in mixed flocks with pelicans and brown noddies.
While some small populations are threatened, the species as a whole is not considered to be globally threatened.
Audubon’s Shearwater itself has around 10 subspecies. Several have at one time or another been suggested to constitute separate species. For example, the Galápagos Islands population has turned out to be a very distinct species, the Galápagos Shearwater is apparently related to the Christmas Shearwater.