One flies down (7)

I believe the answer is:

swallow

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'down' is the definition.
(both can mean to consume or eat)

I cannot understand how the rest of the clue works.

(Other definitions for swallow that I've seen before include "Bird - gulp down" , "It's like a swift - gulp" , "Consume - bird!" , "Fork-tailed bird" , "Creature which can go up" .)

I've seen this clue in The Telegraph.

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