One flies down (7)
I believe the answer is:
swallow
'down' is the definition.
(both can mean to consume or eat)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(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" .)