A parrot, it seems, can put one over on a rooster! (8)
I believe the answer is:
cockatoo
'a parrot' is the definition.
(cockatoo parrot is a kind of parrot)
'one over on a rooster' is the wordplay.
'one' becomes 'a'.
'over' becomes 'too' (I've seen this before).
'on' says to put letters next to each other.
'a rooster' becomes 'cock' ('cock' can be a synonym of 'rooster').
'a'+'too'='atoo'
'atoo' after 'cock' is 'COCKATOO'.
'it seems can put' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for cockatoo that I've seen before include "Bird, a type of parrot" , "Australasian parrot" , "Illegal Aussie look-out man" , "White parrot" , "Lightly coloured crested parrot" .)