Peering aimlessly about, concerning bird (9)
I believe the answer is:
peregrine
'bird' is the definition.
(I know that peregrine is a bird)
'peering aimlessly about concerning' is the wordplay.
'aimlessly' indicates an anagram (the letters rearranged chaotically or aimlessly).
'about' means one lot of letters goes inside another.
'concerning' becomes 're' (both can mean on a particular topic).
'peering' with letters rearranged gives 'pegrine'.
'pegrine' going around 're' is 'PEREGRINE'.
(Other definitions for peregrine that I've seen before include "Powerful falcon" , "bird" , "Large falcon" , "Kind of falcon" .)