Another difficult ID when you only have the app and no book. I think that this could be a White-winged Black Tern in non-breeding plumage but not confident. It and another were amongst a large of terns at Point Maud in Coral Bay, WA. They stood out as the head markings were so different and the white eye-ring seemed unusual. I have included a few photos of different views and comparative birds (which I think include Roseate Terns).
Any help appreciated.
Sue
Had a look in the book and it certainly looks very feasible for a WW Black Tern- book describes 'distinctive earphones head pattern and white hind colllar' which yours has got. Also the white rump on top which appears to be visible in last photo is a diagnostic for WW BT.
Thanks, Whistling Duck. Another new one for me. This trip has been quite interesting with a number of new birds sighted and second sightings of some others. Even saw a vagrant Rosy Starling in Arnhem Land. I will post some pictures from the trip when WiFi is a bit easier to use
Sue
Definitely White-winged Black Tern, aka White-winged Tern. There's 2 of them in the last photo. You also have a Lesser Crested Tern & all the rest appear to be Roseate Terns, except the Tern at the back in the last photo with head obscured, I can't tell what that one is.
Thanks Steven, terns are a challenge but I am starting to get some idea. There were so many that it is taking some time to check through the pictures. These two really stood out. Pleased to get it right and the Roseate. Realised the other was a Lesser Crested but thought that the size comparison would help. Today's treat at Hutt Lagoon (pink lake at Port Gregory,WA) were non-breeding plumage Banded Stilts, another first for me.
Once again, thanks to both of you
Sue