Area by train lines home to birds (6)
I believe the answer is:
aviary
'home to birds' is the definition.
I can't judge whether this definition defines the answer.
'area by train lines' is the wordplay.
I cannot really understand how this works, but
'area' could be 'a' (maths abbreviation) and 'a' is located in the answer.
'by' could be 'via' (travelling by or via a place) and 'via' is found within the answer.
'lines' could be 'ry' (abbreviation for railway) and 'ry' is located in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for aviary that I've seen before include "Building for keeping birds" , "Large cage for birds" , "wildlife centre" , "House for birds" , "Its inhabitants probably like flying" .)