The fulmar prion is a poorly known species that is only easily seen by visiting its remote island breeding sites. It is usually only identifiable in the hand. The species is very similar to the abundant fairy prion but is separable on the basis of its chunkier bill. The specific name crassirostris means ‘thick billed’ in Latin. The Pyramid prion from the Chatham Islands is also very similar, and has an even more robust bill. The fulmar prion is endemic to New Zealand, where it breeds at three southern island groups. Like most petrels, fulmar prions spend most of their life at sea, but their pelagic distribution is poorly known.

Identification

Prions are small petrels. The fulmar prion, like other prions, is blue-grey above with a black 'M' marking between the wing tips, a black tail tip and a white supercilium. Underneath it is largely white. Its bill is mainly bluish-grey; its legs and feet are blue with paler webs and greyer claws. Immatures appear similar.

The lesser fulmar prion is the smaller of the two subspecies, with a less robust bill.

Voice: the fulmar prion is a noisy bird at the nesting colonies both in flight and on the ground, with males giving a four-note call described as what-not-to do and females giving a more slurred, cooing three note call coore-corr-corr . Unlike other prion species, fulmar prions on the Bounty Islands are vocal by day but silent at night.

Similar species: the fulmar prion is separable from most other prion species by its relatively small body and bill size and its more pronounced black tail tip. However, it shares these characteristics with the fairy prion and Pyramid prion, and can usually only be separated from these species in the hand on the basis of bill shape and size (fulmar prion has a bill that is more robust than fairy prion, but not as robust as Pyramid prion).

Distribution and habitat

The nominate subspecies nests at the Bounty Islands and The Snares (Rima and Toru in the Western Chain); the lesser fulmar prion nests at the Auckland Islands (Ewing, Ocean, Rose, Disappointment, and Monumental Islands). Prions breeding on Heard Island (southern Indian Ocean) were confirmed to be fairy prions (cf. fulmar prions) in 2022, making fulmar prion an endemic New Zealand species.

Fulmar prions are commonly seen offshore from their breeding colonies during the breeding season, and the species may be fairly sedentary around its nesting islands in winter, however little is known about its pelagic range as fulmar prions are difficult to identify at sea. It has been seen in the south Tasman Sea, near Stewart Island, and east of the South Island. Fulmar prions rarely reach mainland New Zealand coasts, and are an extreme vagrant to Tasmania.

Population

The total New Zealand population is probably less than 32,000 pairs, including about 30,000 pairs at the Bounty Islands, up to 400-600 pairs at The Snares, and less than 1,000 pairs at the Auckland Islands. 

At the Bounty Islands the population forms "a subterranean population wherever suitable habitat" occurs (Robertson & van Tets 1982).

Threats and conservation

The fulmar prion is confined to nesting on offshore islands free of introduced predators. There is no evidence to show that the species formerly had a wider nesting range, although their apparent absence from the main Auckland Island is likely due to introduced cats, pigs, and mice. Many current nesting sites remain vulnerable to invasion by rats which would have the potential to eliminate populations. Serious pollution incidents, such as oil spills, near breeding sites are also a potential threat. Subantarctic skuas kill some birds on the breeding grounds.

Breeding

Fulmar prions breed in dense to loose concentrations, with the nominate subspecies breeding among nesting albatrosses at its two breeding locations. The breeding biology has not been studied in detail, but it is assumed to be very similar to that of the closely related fairy prion, with a breeding season from October to February. At the Bounty Islands, partly incubated eggs were found on 19 November. At The Snares, eggs have been found from 13 October to 21 November, hatching peaks in mid-December, large downy chicks were seen on 19 January, and fledglings probably leave in early February.

Nests of the nominate subspecies are in natural crevices, rock piles, and caves. The lesser fulmar prion also nests in burrows. Like all petrels, only a single egg is laid.

Behaviour and ecology

Fulmar prions are unusual among prion species for visiting their nest sites in broad daylight at some colonies (Bounty Islands and The Snares), including performing acrobatic courtship displays and intraspecific fighting on the surface of the colonies. Over the Bounty Islands, flocks will pursue and mob predatory gulls or skuas. However, at the Auckland Islands, lesser fulmar prions only come ashore after dark.

Food

Fulmar prions probably catch most of their food close to their breeding islands during the day. They have been seen pecking small items off the sea surface and making brief, shallow dives. Prey consists of a range of small marine invertebrates, varying seasonally, including: crustaceans, juvenile barnacles, salps, pyrosomes, cephalopods and various floating molluscs, and the occasional fish. Snares birds eat mainly crustaceans (euphausiids and amphipods).

Websites

BirdLife factsheet

References

Fleming, C.A.; Baker, A.N. 1973. The Snares Western Chain. Notornis 20: 37-45.

Harper, P.C. 1980. The field identification and distribution of the prions (genus Pachyptila), with particular reference to the identification of storm-cast material. Notornis 27: 235-286.

Heather, B.D.; Robertson, H.A. 1996. The field guide to the birds of New Zealand. Viking, Auckland.

Imber, M.J. 1981. Diets of storm petrels Pelagodroma and Garrodia and of prions Pachyptila (Procellariiformes). Pp. 63-88 in Cooper, J. (ed.). Proceedings of the Symposium on Birds of the Sea and Shore, held at the University of Cape Town, 19-21 November 1979 (ISBN 0620063548). African Seabird Group, Cape Town. 

Jamieson, S.E.; Tennyson, A.J.D.; Wilson, K.-J.; Crotty, E.; Miskelly, C.M.; Taylor, G.A.; Waugh, S.M. 2016. A review of the distribution and size of prion (Pachyptila spp.) colonies throughout New Zealand. Tuhinga 27: 56-80.

Marchant, S.; Higgins, P.J. (Eds.) 1990. Handbook of Australian, New Zealand and Antarctic birds. Vol. 1, ratites to ducks. Oxford University Press, Melbourne.

Miskelly, C.M. 1984. Birds of the Western Chain, Snares Islands, 1983-84. Notornis 31: 209-223.

Miskelly, C.M.; Elliott, G.P.; Parker, G.C.; Rexer-Huber, K.; Russ, R.B.; Taylor, R.H.; Tennyson, A.J.D.; Walker, K.J. 2020. Birds of the Auckland Islands, New Zealand subantarctic. Notornis 67: 59–151.

Miskelly, C.M.; Forsdick, N.J.; Palma, R.L.; Rawlence, N.J.; Tennyson, A.J.D. 2024. Amendments to the 5th edition (2022) of the Checklist of the Birds of New Zealand. Notornis 71: 77–98.

Miskelly, C.M.; Sagar, P.M.; Tennyson, A.J.D.; Scofield, R.P. 2001. Birds of the Snares Islands, New Zealand. Notornis 48: 1-40.

Robertson, C.J.R.; van Tets, G.F. 1982. The status of birds at the Bounty Islands. Notornis 29: 311-336.

Sagar, P.M. 1977. Birds of the Western Chain, Snares Islands, New Zealand. Notornis 24: 178-183.

Shepherd, L.D.; Miskelly, C.M.; Bulgarella, M.; Tennyson, A.J.D. 2022. Genomic analyses of fairy and fulmar prions (Procellariidae: Pachyptila spp.) reveals parallel evolution of bill morphology, and multiple species. PLOS One 17(9) e0275102. https://doi.org/10.1371/journal.pone.0275102

Taylor, G.A. 2000. Action plan for seabird conservation in New Zealand. Part A: threatened seabirds. Threatened Species Occasional Publication No.16. Department of Conservation, Wellington.

Tennyson, A.J.D.; Bartle, J.A. 2005. A scientific name for fulmar prions nesting at Auckland and Heard Islands. Notornis 52: 47-55.

Recommended citation

Tennyson, A.J.D. & Miskelly, C.M. 2024. Fulmar prion. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz