For some idea of the variability in the so-called “mirrors” or “spots” on the outer primaries of Silver Gulls people interested in this topic might find the gallery of Silver Gull images at http://ptiloris.smugmug.com/Birds-of–Oz-Sets/Silver-Gull/9990908_H8hEZ#773685706_V4VyQ interesting.
Image No 13 seems to very well fit the description for the outer primaries of a ‘typical’ adult (non-breeding and breeding) as described in Vol 3 of HANZAB except that the slight clipping of the wing by the bottom edge of the frame means that the apical spots cannot be determined. However, as this is a breeding adult with somewhat worn plumage those spots would probably not be evident anyway.
The other flight shots in the gallery show reasonably well the variation in the actual and/or observed appearance of the white windows on primaries P8 to P10.
All of the images were taken in SE Queensland and I have no reason to believe any of the gulls in the images are other than Silver Gull ( Chroicocephalus novaehollandiae) but I am open to being corrected on that.
Bob Inglis Sandstone Point Qld ===============================
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