Most recent bird sanctuary we found inside (6)
I believe the answer is:
newest
'most recent' is the definition.
('new' can be similar in meaning to 'recent')
'bird sanctuary we found inside' is the wordplay.
'bird sanctuary' becomes 'nest' (I've seen this in another clue).
'found inside' indicates putting letters inside.
'nest' placed around 'we' is 'NEWEST'.
(Other definitions for newest that I've seen before include "Latest novel" , "Freshest, most recent" , "Most pristine or latest" , "Most recent or least worn" , "most recently released?" .)