A small grey-and-white petrel filters krill from seawater using a specialised bill. It operates like a tiny whale with wings. Salvin's prion is one of several prion species found in the Southern Ocean. They all look similar. The differences are subtle. The bill is broader than the fairy prion's. The tail is darker. The bird does not care about these distinctions. Identification requires close observation. Feeding focuses almost exclusively on crustaceans. Krill and copepods are filtered from surface water. The bill is broad and flattened fringed with fine lamellae that act like a sieve. Flight occurs low to the water head submerged paddling forward with feet. A prion feeding is a bird converting seawater into protein. The mechanism is efficient. It relies on density and movement. Flight is rapid and erratic. Twinkling wingbeats alternate with sudden banks. A Salvin's prion in a storm is in its element. It rides the wind tilting from one gust to the next never landing. Stability comes from motion. Stillness is not an option over open water. The bird masters the turbulence rather than resisting it. Breeding takes place on remote subantarctic islands. The burrow is dug into soft soil on a steep slope often under tussock grass or among rocks. A single white egg is laid. Both parents share incubation duties. The chick is fed on regurgitated krill oil. Fledging occurs at about two months. The investment is high for a single offspring. Survival rates depend on ocean productivity. Osbert Salvin gives the species its name. He is the same naturalist honoured in the mollymawk. He never saw this bird either. Taxonomic honours often outpace observation. The name persists regardless of personal experience. The population is enormous. Millions of birds breed on the Bounty Islands the Snares and other subantarctic islands. They are safe there for now. The Bounty Islands are too bare for rats. The Snares are too remote. Isolation provides protection. Geography acts as a barrier against introduced predators. The main threat remains introduced predators. Rats and mice have wiped out prion populations on other islands in the Southern Ocean. A single shipwreck on the Snares could bring rats. The risk is constant. Vigilance is required. Conservation efforts focus on maintaining predator-free status. Salvin's prion is a bird of the open ocean. It comes to land only to breed. Life is spent at sea filtering krill riding the wind. Most people will never see one. The distance is vast. The habitat is inaccessible. The call is a low purring chatter heard only at night. On the Snares with the wind in the tussock and the prions calling the sound is constant. It fills the darkness. It signals presence without visibility. The colony breathes through sound.