Bird with a type of pad is a common tweeter (8)
I believe the answer is:
titmouse
'pad is a common tweeter' is the definition.
I can't judge whether this defines the answer.
'bird with a type of' is the wordplay.
'bird' becomes 'tit' (I've seen this before).
'with' means one lot of letters go next to another.
'a type of' becomes 'mouse' (I am not sure about this - if you are sure you should believe this answer much more).
'tit'+'mouse'='TITMOUSE'
Can you help me to learn more?
(Other definitions for titmouse that I've seen before include "Small songbird" , "Small bird" .)