Blame one when a bird gets out and a reptile (8)
I believe the answer is:
terrapin
'a reptile' is the definition.
(terrapin is a kind of reptile)
'blame one when a bird gets out and' is the wordplay.
I cannot quite understand how this works, but
'blame' could be 'rap' ('rap' can be a synonym of 'blame') and 'rap' is found in the answer.
'one' could be 'i' (Roman numeral) and 'i' is located in the answer.
'when' could be 'e' (I've seen this in other clues) and 'e' is present in the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for terrapin that I've seen before include "A reptile; a printer (anag.)" , "Chelonian reptile" , "Web-footed turtle" , "Small freshwater turtle" , "Partner I found for freshwater tortoise" .)