Frantic bird has hidden in empty crate but it's a pointless pursuit (4-5,5)
I believe the answer is:
wild-goose chase
'pursuit' is the definition.
(I know that wild-goose chase is a type of pursuit)
'frantic bird has hidden in empty crate but it's a pointless' is the wordplay.
I cannot quite understand how this works, but
'frantic' could be 'wild' (similar in meaning) and 'wild' is found in the answer.
'bird' could be 'goose' (goose is a kind of bird) and 'goose' is present in the answer.
'empty' could be 'e' (abbreviation e.g. on guages) and 'e' is found in the answer.
'a' is within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for wild-goose chase that I've seen before include "Hopeless quest" , "Futile quest" , "A foolish pursuit" .)