Perch for birds contains regular debris from male fowl (8)
I believe the answer is:
roosters
'fowl' is the definition.
(I know this)
'perch for birds' is the wordplay.
'perch' becomes 'roost' (roost is a kind of perch).
'for birds' becomes 'ers' (I can't explain this - if you can you should believe this answer much more).
'roost'+'ers'='ROOSTERS'
'contains regular debris from male' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for roosters that I've seen before include "Cockerels" , "Adult male chickens" , "poultry" , "Sore sort of male farmyard birds" , "Domestic cocks" .)