The most common and most likely answer to this crossword clue is the 6 letter word SWIFTS
I've seen this crossword clue in Independent
S
W
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F
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More clues leading to the result SWIFTS
Buddy explains!
The straight part
We know that "birds" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case birds = swifts.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SWIFTS mean?
SWIFTS noun- A small plain-colored bird of the family Apodidae that resembles a swallow and is noted for its rapid flight.
- Any of certain lizards of the genus Sceloporus.
- A moth of the family Hepialidae, swift moth, ghost moth.
- Any of various fast-flying hesperiid butterflies.
- A reel for winding yarn.
- The main cylinder of a carding-machine.
- The current of a stream.