Flier taken over Eastern mountain (5)
I believe the answer is:
grebe
'flier' is the definition.
(grebe is a kind of birdanimal)
'taken over eastern mountain' is the wordplay.
I cannot quite understand how this works, but
'over' could be 're' and 're' is found within the answer.
'eastern' could be 'e' and 'e' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for grebe that I've seen before include "Diver" , "Flier" , "Diving water bird" , "Diving waterbird" , "Diving bird which may be crested" .)