Hello,
the main aim for my comment is to bump this interesting thread up, hoping for others to jump in.
First: the adult Tern is a Common Tern (or are there two of them?) imo, by dark wedge of outer primaries and long bill.
The 1cy bird in picture 7 is a Common Tern, too: please note dark secondary-bar and pale midpanel on the arm as the palest part of the wing.
The other two 1 cy birds are more difficult for me:
first, assuming that the 1cy Common Tern from picture 7 is one of the young trio, it is obvious, that confident assesment of the wing-pattern is difficult here.
Or is it a different bird? Then it looks slightly better for a 1cy Arctic Tern imo.
And I think, this is one of the main reasons for the lack of comments so far, the other is the mixture of different birds (no offence you know).
The other two 1cy birds look good for Arctic Terns imo:
both seems to have
- pale secondaries,
- the pale area reaches onto the inner primaries at least
- I think, I can make out the indication of an tri-coloured wing with a pale wedge on the rear-wing (or is it wishful thinking, enhanced by picture quality and light situation?)
- the right bird has a round head with shortish (not ID-friendly short) bill, the other one is not so easy for me.
Conclusion?
I think your pictures shows one adult Common Tern (or two similar birds?), one 1 cy Common Tern and two (or three?) 1cy Arctic Terns.
But better wait for confirmation or correction. Thans!
