Flier in dire distress at the end of the line (5)
I believe the answer is:
eider
'flier' is the definition.
(eider is a kind of birdanimal)
'dire distress at the end of the line' is the wordplay.
'distress' is an anagram indicator.
'at the end of' suggests the final letters.
'line' indicates putting letters inside.
The final letter of 'the' is 'e'.
'dire' is an anagram of 'eidr'.
'eidr' placed around 'e' is 'EIDER'.
'in' is the link.
(Other definitions for eider that I've seen before include "Sea duck with soft down" , "Large sea duck" , "Duck valued for its fine soft down" , "Variety of duck" , "Sea-duck" .)