Continue to have a pet bird (4,2,2)
I believe the answer is:
keep at it
'continue' is the definition.
(I've seen this before)
'have a pet bird' is the wordplay.
I cannot quite see how this works, but
'have' could be 'keep' (keeping is a kind of having) and 'keep' is present in the answer.
'a' is present in the answer.
'bird' could be 'tit' (tit is a kind of bird) and 'tit' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'to' is the link.
Can you help me to learn more?
(Other definitions for keep at it that I've seen before include "carry on" , "Continue" , "Persevere" .)