A new bird for New Zealand – MacGillivray’s prion

Prions are a group of small seabirds that are very difficult to tell apart. This is part of the reason why it took more than 70 years to identify New Zealand’s first MacGillivray’s prion. Bird curator Colin Miskelly describes how modern genetic methods were used to identify old museum specimens – and to add a new species to the New Zealand and Australian lists.

An identity problem

MacGillivray’s prion was described from tiny Saint Paul Island in the southern Indian Ocean in 1912, and largely ignored for the next 100 years. It has variously been considered as a subspecies of broad-billed prion, a subspecies of Salvin’s prion, lumped with broad-billed prion, or treated as a full species in its own right.

About a decade ago, genetic research revealed that MacGillivray’s prions were most closely related to broad-billed prions. As both these prions breed side-by-side without interbreeding on Gough Island (in the South Atlantic), they are now treated as separate species.

First indication that MacGillivray’s prion might reach Aotearoa

In 2022, Karine Delord and her colleagues from Centre d’Études Biologiques de Chizé published a study showing that some MacGillivray’s prions from St Paul Island spent the 2018 winter in the Tasman Sea. The species was not otherwise known to occur in New Zealand (or Australia), and so we decided to use genetic methods to search for MacGillivray’s prions among prion specimens recovered from New Zealand beaches and held in the Te Papa collection.

Hidden in plain sight

MacGillivray’s prions have bills that are between those of broad-billed prions and Salvin’s prion in size. We developed measurement criteria to select birds that fell between these two species in bill size, and screened tissue samples from these ‘intermediate’ museum specimens using genetic techniques.

Most of these ‘intermediate’ specimens proved to be large-billed Salvin’s prions. However, a single bird had bill measurements, mitochondrial DNA and nuclear DNA that all matched MacGillivray’s prion. This bird had washed ashore on Ōtaki Beach, Horowhenua, in July 1954, and had been identified and catalogued as being a broad-billed prion.

The evidence on this bird’s identity was assessed by the Birds New Zealand Records Appraisal Committee, who unanimously agreed that MacGillivray’s prion should be added to the New Zealand list.

But wait, there’s more…

As often happens with science, the full answer turned out to be more complex and interesting than the original question. Using the same methods, we were able to identify four prions from Australian beaches (all held by South Australia Museum) as also being MacGillivray’s prions. However, all five Australasian specimens had bill measurements and mitochondrial DNA that matched birds from Gough Island in the South Atlantic.

We had set out to confirm the results of the French geolocator tracking study of prions from St Paul Island (about 3,000 km south-west of Australia). We didn’t find any of them among the Te Papa or South Australia Museum collections – instead, we found MacGillivray’s prions that had reached Australasian shores from their only other breeding site, more than 10,000 km away!

This multi-national collaboration included museum samples and field data from New Zealand, Australia, French subantarctic territories, and South Africa, and was published in the journal Emu – Austral Ornithology:

Miskelly, C.M.; Tennyson, A.J.D.; Horton, P.; Penck, M.; Ryan, P.G.; Barbraud, C.; Delord, K.; Shepherd, L.D. 2025. Hidden in plain sight: DNA sequencing of museum specimens confirms the occurrence of MacGillivray’s prion (Pachyptila macgillivrayi) in Australia and New Zealand. Emu – Austral Ornithology DOI:
10.1080/01584197.2025.2490644

Miskelly et al. 2025. Hidden in plain sight eprint link

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