What the birds do when he teases them? (7)
I believe the answer is:
'what the birds do when he teases them?' is the definition.
The definition suggests a singular noun which matches the answer.
'what the birds do when he' is the wordplay.
I cannot quite see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
'he' could be 'wit' and 'wit' is found within the answer.
The remaining letters 'ter' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for twitter that I've seen before include "where characters are restricted" , "Social media provider" , "Utter tremulous sounds" , "There's birdsong" , "state of excitement" .)