Jackdaw nest concealed when day breaks (4)

I believe the answer is:

dawn

'when day breaks' is the definition.
(dawn is daybreak)

'jackdaw nest concealed' is the wordplay.
'concealed' says the answer is hidden in the clue.
'DAWN' can be found hidden inside 'jackdaw nest'.

(Other definitions for dawn that I've seen before include "First light" , "Daybreak" , "Threshold" , "Early morning sing-song?" , "Aurora, poetically" .)

I've seen this clue in The Guardian.

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