Bird with a sharp point to its tail (7)
I believe the answer is:
bittern
'bird' is the definition.
(bittern is a kind of bird)
'sharp point to its tail' is the wordplay.
I cannot really see how this works, but
'sharp' could be 'bitter' (I've seen this before) and 'bitter' is located in the answer.
'point' could be 'n' (North) and 'n' is located in the answer.
No letters remain.
This explanation may well be incorrect...
'with a' acts as a link.
Can you help me to learn more?
(Other definitions for bittern that I've seen before include "Booming marsh bird" , "Marsh bird of the heron family" , "Bird that booms" , "flier" , "Source of boom" .)