Tough old bird's lost after terrible tale (8)
I believe the answer is:
leathern
'tough old' is the definition.
The definition suggests an adjective which matches the answer.
'bird's lost after terrible tale' is the wordplay.
'bird's lost' becomes 'hern' (I am not sure about this - if you are sure you should believe this answer much more).
'after' says to put letters next to each other.
'terrible' is an anagram indicator.
'tale' with letters rearranged gives 'leat'.
'hern' after 'leat' is 'LEATHERN'.
Can you help me to learn more?
(Another definition for leathern that I've seen is " hide".)