Cry of bird beginning to hover above (4)
I believe the answer is:
howl
'cry' is the definition.
(howl is a kind of cry)
'bird beginning to hover above' is the wordplay.
'bird' becomes 'owl' (owl is a kind of bird).
'beginning to' suggests taking the first letters.
'above' means one lot of letters go next to another (in a down clue, some letters go above others).
The initial letter of 'hover' is 'h'.
'owl' put after 'h' is 'HOWL'.
'of' acts as a link.
(Other definitions for howl that I've seen before include "Long cry of dog" , "Laugh (or cry?)" , "Lazy person" , "Plaintive wolf cry" , "Long wailing cry" .)