#oceanites

Wilson's Storm Petrel (Oceanites oceanicus), family Oceanitidae, order Procellariiformes, off the coast of QLD, Australia

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Wilson’s Storm Petrels (Oceanites oceanicus), family Oceanitidae, order Procellariiformes, off the Coast of Portugal

Wilson’s Storm Petrels (Oceanites oceanicus), family Oceanitidae, order Procellariiformes, off the Coast of Portugal

Wilson’s Storm Petrel by Richard Crossley, CC BY-SA 3.0 

Etymology: For the mythical Oceanids, daughters of Tethys, Titan wife of Oceanus

First Described By: Keyserling & Blasius, 1840

Classification: Dinosauromorpha, Dinosauriformes, Dracohors, Dinosauria, Saurischia, Eusaurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Maniraptoromorpha, Maniraptoriformes, Maniraptora, Pennaraptora, Paraves, Eumaniraptora, Averaptora, Avialae, Euavialae, Avebrevicauda, Pygostaylia, Ornithothoraces, Euornithes, Ornithuromorpha, Ornithurae, Neornithes, Neognathae, Neoaves, Aequorlitornithes, Ardeae, Aequornithes, Austrodyptornithes, Procellariiformes, Oceanitidae

Referred Species: O. oceanicus (Wilson’s Storm Petrel), O. gracilis (Elliot’s Storm Petrel), O. pincoyae (Pincoya Storm Petrel)

Status: Extant, Least Concern - Data Deficient

Time and Place: From 5.33 million years ago until today, in the Zanclean of the Pliocene through the Holocene of the Quaternary 

This genus of Storm Petrel is known from around the world, mainly in the southern hemisphere, associated with the oceans and coasts 

Physical Description: The species of Oceanites are actually quite small as far as storm petrels go - literally, the same length in body as your average passerine. They range from 15 to 20 centimeters in length, though they do have wingspans that are twice as long as their body length. These birds are brown to grey in color, with distinctive white banding across the tops and undersides of their wings and bellies. They have white stripes across their tails, but overall the ends of their tails match the rest of their bodies. They have long, thin legs, and tiny heads with tiny bills. Beyond that, there are differences among the species, mainly in specifics of coloration and banding. The juveniles are similar to the adults, but potentially with more white feathers; and all sexes look alike. 

Elliot’s Storm Petrel by Putney Mark, CC BY-SA 2.0 

Diet: These storm petrels mainly feed on crustaceans and fish, in addition to squid, polychaetes, gastropods, and occasionally meat.

Behavior: These birds will feed mainly on the wing, going over the surface of the water and dipping in for food. They’ll even follow ships in order to get the food washed up and exposed by the disturbance. They both dip for food and patter for food, though they do engage in some surface-diving in order to get food. They can even smell food brought up by other sources, including those surfaced by whales. They rarely forage in groups of more than two, though it can happen. They are somewhat loud birds, making incessant chattering noises to one another, including very nasal and grating calls. They don’t vocalize above the breeding colonies, but instead perform aerial displays. The Pincoya and Elliot’s storm petrels don’t migrate, or only migrate a little bit; Wilson’s turns it into an artform. They move across the Atlantic, Indian, and Pacific oceans according to food availability and shifts in the weather and season. They concentrate especially during the breeding season, with millions of birds seen at solitary breeding sites around South America. 

Pincoya Storm Petrel by Cristian Pinto, CC BY-SA 4.0 

These petrels breed beginning in December, with a large migration of females over the course of two weeks to reach the breeding season. Egg laying occurs over the next three to six weeks, and they are nocturnal during this time to protect the young. They mate with a single mate and these pair-bonds are usually formed over the course of their whole lives. They lay their eggs in burrows, rock crevices, and other hiding spots - usually bare, but sometimes lined with moss and feathers. They usually lay a single white egg that is protected by both parents. The chick will hatch usually in Late January, with some chicks seen as late as March. The chicks are dark grey and fluffy and brooded for a few days before being fed and watched for seven more weeks. They reach sexual maturity at three years old, and most adults will survive to that point. 

Wilson’s Storm Petrel by Patrick Coin, CC BY-SA 2.5

Ecosystem: These birds are usually associated with marine environments, going to the coasts when needed but essentially spending all their time in pelagic waters. That being said, the Pincoya species is rarely found away from inland species. Wilson’s breeds on rocky islets, cliffs, and boulder scree - the breeding habitats of the other two species are unknown. The adults and the chicks are hunted by South Polar Skuas and Long-Tailed jaegers.

Other: These petrels are not considered endangered, though Elliot’s and the Pincoya species are both so poorly known their conservation status is uncertain at this time - they overlap in range with Wilson’s, and the Pincoya species was only named a few years ago! That being said, there are millions of these birds known, but they - like all living things - are threatened currently by human activity, especially in this case competition with commercial fisheries. 

Wilson’s Storm Petrel by J. J. Harrison, CC BY-SA 3.0 

Species Differences: Wilson’s Storm Petrel, the best known species, lives entirely worldwide; It has dark brown edges to its wings, while its body and the tops of its wings are a lighter brown - it barely has white stripes across its wings at all. Elliot’s Storm Petrel is known from across the western coast of South America, and it is the same lighter brown as Wilson’s - except it has extensive white striping across the underside of its wing and along its belly. Finally, the Pincoya Storm Petrel is only known from a tiny portion of Chile, and it is more of a dark grey in color, with white striping across the tops and undersides of its wings.

~ By Meig Dickson

Sources under the Cut 

Some rare photographs of a Pincoya Storm petrel (Oceanites pincoyae) from Puerto Montt, in the south of Chile.

This bird was spotted for the first time in 1983, but was recently described in 2013, at that time, a new petrel hadn't been spotted in 89 years.

The specific name pincoyae commemorates the Pincoya, a female water spirit of the southern Chile’s mythology