BirdingNZ.net

Whatever it is, that dark patch on the mantle looks odd.

No Antarctic Tern today but did see the WWBT.

Michael

The dark mark on the side of the neck is just part of the normal juvenile plumage of at least some White-fronted and Antarctic Terns.

Ian

Either way, it would be good to post examples of this plumage on the relevant NZ Birds Online pages as there aren't a lot of photos of juveniles for both WFT and Antarctic Tern.

I also think it is a White fronted, similar to this one,probably the most obvious choice to start with anyway.

Thank you for this image Steve. Definitely looks like the tern I saw.

Thanks for posting that shot, Steve. As Ben says, it looks very similar with that dark bar near the nape. The only shot of a young WFT in flight on the NZ Birds Online website is the one below taken by Ormond Torr, which doesn't have that dark bar near the nape, so it would be good to send more photos of young WFTs in flight to Colin Miskelly for him to add to the website:
https://nzbirdsonline.org.nz/species/white-fronted-tern

I also checked the Antarctic Tern page and there are no photos of young ATs in flight, so ditto for them if anyone has any photos they can send to Colin.

This one from Same spot last evening. And a few skua bombs to boot!