Bird safe lifting tail perched on line (6)
I believe the answer is:
petrel
'bird' is the definition.
(petrel is a kind of bird)
'safe lifting tail perched on line' is the wordplay.
I cannot really understand how this works, but
'on' could be 're' ('on' can be mean 'with reference to') and 're' is found in the answer.
'line' could be 'l' (used when specifying particular lines from a poem) and 'l' is found in the answer.
The remaining letters 'pet' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for petrel that I've seen before include "Mother Carey's chicken" , "Bird that sounds like fuel" , "Storm bird" , "Seabird (that may be stormy)" , "Bird of storms at sea" .)