Red-billed Gull with three primary mirrors

[Matthias]

Hi,
rarely, Red-billed/Silver Gull ssp. scopulinus can have white mirrors on the three outermost primaries (instead of the usual two). Does anyone know of photos of such birds? Apparently, there is one depicted on page 267 in Oliver (1930) New Zealand Birds, but unfortunately, I currently only have access to the second edition of this book (1955) which does not include the photo.
I ask because I have photos of Red-billed Gulls with three primary mirrors, and there are additional photos on eBird. I would like to find out if these are unusual scopulinus or rather visiting birds from Australia.
Cheers
Matthias

[Jake]

Here's the image

[Matthias]

Hi Jake,
great, thanks a lot!

[Clinton9]

During summer of 2000, I had seen a 1-year Red-billed gull with three mirrors on primaries 8th to 10th, as it moulting from first summer plumage, into second winter plumage.

Some Red-billed gulls do have three mirrors on primaries 8th to 10th, but majorly of adult Red-billed gulls have two mirrors on primaries 9th to 10th.

[Oscar Thomas]

Here's a gull with three mirrors from Aramoana yesterday, and a much better example from eBird: https://ebird.org/checklist/S59917276