The Pyramid prion is a poorly known species that is only easily seen by visiting its remote island breeding sites. Formerly considered a subspecies of fulmar prion, genomic analyses revealed Pyramid prion to be more closely related to fairy prion than it is to fulmar prion. It is very similar to the fairy prion and fulmar prion, but is separable on the basis of its more robust bill. The specific name pyramidalis refers to the type locality and main breeding site on The Pyramid (Pyramid Rock / Tarakoikoia) in the Chatham Islands. The Pyramid prion is endemic to the Chatham Islands. Like most petrels, Pyramid prions spend most of their life at sea, but their pelagic distribution is poorly known.

Identification

Prions are small petrels. The Pyramid 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 chunky bill is mainly bluish-grey; its legs and feet are blue with paler webs and greyer claws. Immatures appear similar.

Voice: cackling and purring calls, similar to other prion species.

Similar species: the Pyramid prion is separable from most other prion species by its very robust bill and its more pronounced black tail tip. However, it shares these characteristics with the fulmar prion and can only be separated from this species in the hand on the basis of its even more robust bill.

Distribution and habitat

Breeds only on The Pyramid / Tarakoikoia and the Forty-Fours / Motuhara, Chatham Islands.

Pyramid 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 Pyramid prions are difficult to identify at sea. Birds likely to have been this species have been seen well east of the Chatham Islands at 50˚S 156˚W. Pyramid prions rarely reach mainland New Zealand coasts.

Population

The total population is probably less than 5,000 pairs.

Threats and conservation

Fossil remains have been identified from Chatham and Pitt Islands. The two nesting sites are vulnerable to invasion by rats which would have the potential to eliminate the 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

Pyramid prions breed in crevices and burrows among albatross nests, with some burrows dug into the base of mollymawk ‘chimney’ nests. 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. Incubation has been reported from early to mid-December.

Like all petrels, only a single egg is laid.

Behaviour and ecology

Unlike fulmar prions, Pyramid prions are mainly active ashore nocturnally.

Food

Pyramid prions feed mainly on pelagic barnacles.

Websites

BirdLife factsheet

References

Fleming, C.A. 1939. Birds of the Chatham Islands, Part 1. Emu 38: 380–413.

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.; 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.

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.; Mayhill, R.C.; Clark, G.S. 1993. A visit to The Pyramid and the Murumurus, Chatham Islands.  Tane 34: 171–179.

Recommended citation

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