One on board early regularly to see breeding colony (7)

I believe the answer is:

rookery

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'breeding colony' is the definition.
(I've seen this before)

'one on board early regularly' is the wordplay.
'one on board' becomes 'rook' (I can't justify this - if you can you should give a lot more credence to this answer).
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'early' are 'ery'.
'rook'+'ery'='ROOKERY'

'to see' acts as a link.

Can you help me to learn more?

(Other definitions for rookery that I've seen before include "Seal, penguin, colony" , "breeding ground" , "Lofty breeding-place" , "Noisy bird colony" , "Breeding-place of birds, penguins, seals" .)

I've seen this clue in The Guardian.

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