Notices report about Robin and The Penguin's group

I believe the answer is:

seabirds

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'notices' is the definition.
Although both the answer and definition are plural nouns, I cannot see how they can define each other.

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Another definition for seabirds that I've seen is " Fliers".)

I've seen this clue in the Irish Times.

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