Antarctic Prion

Identification

The Antarctic prion is the largest member of the prion genus, measuring 27 cm in length with a wingspan of 61–66 cm and weighing 150–160 g. Like all prions, it displays white underparts contrasting with blue-grey upperparts, and a distinctive dark "M" marking across its back and wings. The species has a white eyebrow stripe, blue-grey bill, and bright blue feet. Its tail is grey and wedge-shaped with a black tip, and the greater wing coverts are nearly black. It is so similar in appearance to Salvin's prion that the two cannot be reliably distinguished at sea.

Range & Habitat

The Antarctic prion breeds in colonies across the Southern Ocean, with established populations on the Auckland Islands, Heard Island, Macquarie Island, Scott Island, South Georgia, the South Sandwich Islands, South Orkney Islands, South Shetland Islands, Crozet Islands, and Kerguelen Islands. Outside the breeding season, the species ranges throughout the southern oceans across a vast occurrence range of 76.6 million square kilometers.

Behaviour & Diet

Antarctic prions feed primarily on zooplankton, which they obtain by a specialized filtration feeding technique—drawing water through their uniquely structured upper bill. Like other members of the order Procellariiformes, they possess naricorns (nasal passages attached to the upper bill) and produce stomach oil rich in wax esters and triglycerides. This oil serves multiple functions: it can be sprayed defensively against predators and provides energy-rich nutrition for chicks and adults during long ocean flights. A specialized salt gland above the nasal passage helps desalinate their bodies, excreting excess salt through the nostrils. The species nests in colonies and practices biparental care, with both sexes sharing nest construction, egg incubation, and chick-rearing duties.

Best Time & Places to See It

The Antarctic prion's breeding colonies on sub-Antarctic islands offer the most reliable viewing opportunities during the breeding season. Key locations include South Georgia, the South Shetland Islands, Kerguelen Islands, and Macquarie Island. Outside breeding season, sightings at sea throughout the southern oceans are possible, though the species' preference for remote waters and its similarity to Salvin's prion make identification challenging. The species has a robust global population estimated at 50 million adults.

Photography Tips

Photographing Antarctic prions requires patience and access to their remote breeding islands or pelagic seabird expeditions. The distinctive dark "M" marking across the back and wings is a key identifying feature to capture. The contrast between white underparts and blue-grey upperparts is striking in good light. At sea, photograph the species in profile to document the white eyebrow and black-tipped tail. Given the challenge of distinguishing this species from Salvin's prion at distance, capture detailed shots of the head pattern, bill coloration, and wing markings for reliable identification. Early morning light often provides optimal contrast for documenting plumage patterns.