Scots valley eagle needs to cover (4)
I believe the answer is:
glen
'scots valley' is the definition.
(I've seen this before)
'eagle needs to cover' is the wordplay.
'to cover' says the answer is hidden in the clue (I've seen 'covered' mean this (the answer is covered up by the clue)).
'GLEN' is hidden within 'eagle needs'.
(Other definitions for glen that I've seen before include "Highland valley" , "Narrow secluded valley in mountains" , "Narrow valley with a stream" , "Narrow Scots valley" , "Campbell perhaps" .)