High jinks - and they’re often very high! (5)

I believe the answer is:

larks

I'm a little stuck... Click here to teach me more about this clue!

'high jinks' is the definition.
(I've seen this in another clue)

I don't understand the remainder of the clue.

(Other definitions for larks that I've seen before include "Frolics" , "Fun and games" , "Early birds" , "High jinks" , "early risers?" .)

I've seen this clue in the Evening Standard.

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