The Wilson’s Storm-Petrel spends its entire life out at sea, with its breeding grounds located offshore as well. They only return to their nests at night to avoid predators, and they are even less likely to return during bright moonlit nights. Because of this, sightings from the mainland are extremely rare.
The Wilson’s Storm-Petrel is named after the ornithologist Alexander Wilson (1766 – 1813). They belong to the Petrel family (a diminutive of the word “Peter” – Saint Peter) due to the remarkable abilities of these birds. Their scientific name is Oceanites oceanicus.
Despite their small size, measuring about 18 cm in length and with a wingspan of approximately 40 cm, they spend their entire lives on the waves far offshore, only flying to land during the breeding season. Though small, they are powerful fliers, capable of maintaining their position in the air even in winds up to 40 nautical miles per hour.
When foraging, they appear to be dancing on the water’s surface, with their wings raised high forming a V shape and their tail spread like a fan, while their feet lightly touch the water. Their webbed feet make them well-suited for this unique performance.
Wilson’s Storm-Petrels primarily feed on zooplankton and also consume oil and fat released from the bodies of marine mammals such as whales and beaked dolphins.
The appearance of Wilson’s Storm-Petrel is quite distinctive: their upper feathers are black, with a small white patch near the tail. When their tail is spread, it forms a relatively square angle. They have long legs with yellow webbed feet. Males and females are very similar in color and size.
Although they mainly reside offshore, they occasionally venture into bays and river mouths (usually following ships). While they are not professional divers, they can dive briefly to catch food. Typically, these birds are quiet, but during courtship, they emit loud calls. Pairs of male and female often stand together, preening each other’s head feathers…
From December to January, the female lays a single white egg in a crevice or a specially dug burrow (by both the male and female). The egg is incubated alternately by both parents for about 48 hours at a time, with incubation lasting between 39 to 48 days. The chicks are cared for by both parents and are fed regurgitated food.
In winter, they migrate from Antarctica to the equatorial regions of the Atlantic, Indian, and Pacific Oceans; some even migrate to the eastern Pacific. They return to Antarctica in November or mid-December. Ornithologists believe that Wilson’s Storm-Petrel is one of the most numerous bird species in the world.
Wilson’s Storm-Petrel has an excellent memory; flocks that have flown all over the world will return to the exact location of their old nesting sites when they come back to breed. Each nest is maintained from year to year.
At their nesting sites, Wilson’s Storm-Petrels often fall prey to the skua (Catharacta stercorarius), and the chicks (occasionally even adults) can die due to heavy snowfall covering their nests.
