Puffinus and cold waters. These tubenose birds fly with stiff wings, and use a shearing flight technique to move across wave fronts with the minimum of active flight. Some small species, such as the Manx shearwater, are cruciform in flight, with their long wings held directly out from their bodies. Many are long-distance migrants, perhaps most spectacularly the sooty and short-tailed shearwaters, which perform migrations of 14,000 km or more each year. "Puffinus" shearwaters come to islands and coastal cliffs only to breed. They are nocturnal at the colonial breeding sites, preferring moonless nights to minimise predation. They nest in burrows
Audubon's shearwater homogeneous north-western Indian Ocean range, but not in the ecologically more diverse and by far larger Pacific range of "dichrous". These unresolved problems notwithstanding, this clade – possibly including the preceding one – has been proposed to constitute a separate species, the tropical shearwater or Baillon's shearwater, "Puffinus bailloni". These taxa could not be included in the most recent studies due to lack of material. The case of "gunax" seems fairly straightforward – as certainly as this can possibly be said in the absence of new data, it belongs to the "bailloni" clade either as a distinct subspecies, or, more