A flighty bird, we believe (7)

I believe the answer is:

swallow

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'believe' is the definition.
(to swallow something is to accept or believe it)

I cannot understand how the remainder of the clue works.

(Other definitions for swallow that I've seen before include "Bird - drink" , "flier" , "put up with" , "Songbird" , "Buy < and consume" .)

I've seen this clue in the Evening Standard.

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