White-chinned petrel
Large Southern Ocean petrel vulnerable to longline fisheries.
The white-chinned petrel (Procellaria aequinoctialis), also called the Cape hen or shoemaker, is a large seabird belonging to the Procellariidae family. It lives across the Southern Ocean, reaching as far north as southern Australia, Peru, and Namibia, and nests in colonies on scattered islands. Scientists once thought it was the same species as the spectacled petrel (Procellaria conspicillata).
In 1747, English naturalist George Edwards illustrated and described the bird in the second volume of *A Natural History of Uncommon Birds*, calling it "The great Black Peteril" based on a preserved specimen brought to London, likely from near the Cape of Good Hope. Swedish naturalist Carl Linnaeus later placed it in the genus *Procellaria* in the tenth edition of *Systema Naturae* (1758), giving it the binomial name *Procellaria aequinoctialis*. Two subspecies are recognized: *P. a. aequinoctialis*, which breeds on temperate and subantarctic islands in the South Atlantic and South Indian Oceans and winters throughout those waters, and *P. a. steadi*, which breeds on New Zealand’s subantarctic islands and winters across the South Pacific. They were considered identical until 2022, when the International Ornithological Congress split them based on strong genetic differences.
The genus name *Procellaria* comes from the Latin *procella* meaning "storm" or "gale," and the species name *aequinoctialis* is Latin for "equinoctial" (from *aequinoctium*, "equinox"). The common name "petrel" refers to Saint Peter walking on water, as these birds appear to run on the water’s surface when taking flight. Other English names are Cape hen and shoemaker. As a member of the order Procellariiformes, the white-chinned petrel shares several features: nasal passages (naricorns) on top of the upper bill; a bill split into seven to nine horny plates; a stomach oil made of wax esters and triglycerides, stored in the proventriculus and used for defense or as energy-rich food for chicks and adults during long flights; and a salt gland above the nasal passage that helps desalinate their bodies by excreting a concentrated saline solution from the nose.
The white-chinned petrel measures 51–58 cm (20–23 in) in length with a wingspan of 134–147 cm (53–58 in). Males are heavier, averaging 1,390 g (49 oz), while females average 1,280 g (45 oz). It is the largest *Procellaria* petrel and the large
- Scientific name
- Procellaria aequinoctialis
- Family
- Procellariidae
- Order
- Procellariiformes
- Length
- 51–58 cm
- Wingspan
- 134–147 cm
- Weight
- 1,280–1,390 g
- Conservation status
- Vulnerable (IUCN)
Lore & Background
The white-chinned petrel was first illustrated and described by English naturalist George Edwards in 1747 in his A Natural History of Uncommon Birds, under the name 'The great Black Peteril.' Edwards based his hand-coloured etching on a preserved specimen brought to London, believed collected near the Cape of Good Hope. In 1758, Carl Linnaeus placed it in the genus Procellaria and coined the binomial name Procellaria aequinoctialis, citing Edwards' work. The genus name Procellaria derives from the Latin procella meaning 'storm' or 'gale,' and the specific epithet aequinoctialis is Latin for 'equinoctial,' referring to the equinox. The common name 'petrel' refers to Saint Peter walking on water, alluding to the bird's habit of appearing to run on the water's surface when taking flight.
Reader's Guide
The white-chinned petrel is the largest species in the genus Procellaria and the largest in its family outside the giant petrels. It is sooty-black with white on its throat and chin, more so in the Indian Ocean sector than the Atlantic. It breeds on islands such as South Georgia (2,000,000 pairs), the Kerguelen Islands (175,000–226,000 pairs), and Disappointment Island (100,000 pairs), among others. Its diet consists mainly of krill and fish, and it readily follows ships to collect fisheries discards, making it vulnerable to longline fisheries. Mortality from longline fisheries has caused the IUCN to classify it as vulnerable, with population declines recorded at Bird Island (28% drop in burrow occupancy), Prydz Bay (86% reduction), Marion Island (14.5% reduction), and the Crozet Islands (37% reduction). Invasive species such as brown rats and black rats have also harmed the species. Conservation measures include ongoing monitoring, elimination of invasive species, and promotion of mitigation measures via ACAP, FAO, and CCAMLR.
Did You Know?
- The white-chinned petrel was first described by George Edwards in 1747 as 'The great Black Peteril.'
- It has two subspecies: P. a. aequinoctialis and P. a. steadi, recognized as distinct by the International Ornithological Congress in 2022.
- The species produces a stomach oil made of wax esters and triglycerides, used for defense and as an energy-rich food source.
- A vagrant white-chinned petrel was recorded in Great Britain in May 2020, the second record of this species in the North Atlantic.
Frequently Asked Questions
Who is the White-chinned Petrel?
The White-chinned Petrel (Procellaria aequinoctialis) is a large seabird in the Procellariidae family, order Procellariiformes, also nicknamed the Cape hen or shoemaker. It breeds in colonies on scattered islands throughout the Southern Ocean.
How big is the White-chinned Petrel?
Adults measure 51 to 58 cm in body length with a wingspan of 134 to 147 cm, and they tip the scales at roughly 1,280 to 1,390 grams. Those dimensions place it firmly among the larger petrel species.
Where does the White-chinned Petrel live?
Its core range spans the Southern Ocean, but individuals have been recorded as far north as southern Australia, Peru, and Namibia. It nests in colonies on scattered islands across that broad band.
How was the White-chinned Petrel first described by science?
English naturalist George Edwards illustrated and named the bird in 1747 in volume two of his *A Natural History of Uncommon Birds*, calling it "The great Black Peteril" after examining a preserved specimen. For many years after, researchers lumped it together with the spectacled petrel (Procellaria conspicillata) before the two were split into separate species.
Why is the White-chinned Petrel important?
As a large predator in Southern Ocean food webs, it helps regulate fish and squid populations, yet it faces serious pressure from longline fisheries bycatch. Its vulnerable status makes it a key indicator species for the health of sub-Antarctic marine ecosystems.
More in Birds of the Indian Ocean 1-24
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