Identifying MacGillivray's prions

[Ian McLean]

Kia ora
I was just wondering whether there is any bill profile card or any detailed list of identifying features that could assist in identifying possible MacGillivray's prions ?

As previously advised by Colin MisKelly, the reason I ask, is that a research paper titled At-sea behavioural ecology of the endangered MacGillivray’s prion from Saint Paul Island: combining tracking and stable isotopes has indicated that some MacGillivray's prions over winter in the Tasman Sea.
https://www.int-res.com/abstracts/meps/v697/p149-165/

It is possible that MacGillivray's prions could be beach wrecked on west coast beaches & any reference material in trying to separate these from the similar Salvin's prion would be much appreciated. Any information such as updated details on wing lengths, tail length, plumage differences & even a bill profile card etc would be great. Although, I am not sure if a bill profile card would be useful, as the average bill width for a Salvin's prion is 17.1mm, whilst the average bill width for a MacGillivray's prion is 17.3mm !

Attached is a picture of a Salvin's prion that we recently found on one of our Birds New Zealand, beach patrols of Muriwai Beach in west Auckland. This particular bird has been taken to the Auckland Museum as a specimen, as we intend to take all Salvin's prions we find to the museum for the museum staff to have a closer look at.

Regards
Ian McLean

[Colin Miskelly]

Kia ora Ian and all

This is a topic that the Te Papa birds / genetics team are currently investigating, and intend to publish a paper on this in the next 12 months. In the interim, the only way to separate MacGillivray's prion and Salvin's prion is based on their genetic profile. If anyone wishes to include any beach patrol specimens in the study (or have them identified), you are welcome to send them to Te Papa.

Ngā mihi
Colin

[Michael Szabo]

Thanks for these updates, exciting stuff. I wonder if the MacGillivray's Prions that breed at St Paul and Gough islands are being banded, or whether there are any photos of them in the hand showing bill structure and colour?

[Michael Szabo]

These photos of birds in flight off Uruguay and Argentina have been published here:
https://link.springer.com/article/10.10 ... wHwIKrWdq8

There is more information on bill length here:
More details on bill measurements here: https://link.springer.com/article/10.10 ... 21-01845-3

And more photos here, including a close view of the bill:
https://ebird.org/species/salpri3