Sang wildly about ten rising fliers (7)
I believe the answer is:
gannets
'fliers' is the definition.
(gannet is a kind of bird)
'sang wildly about ten rising' is the wordplay.
'wildly' indicates an anagram.
'about' is an insertion indicator.
'rising' shows that the letters should be reversed in order (going up in a down clue).
'ten' back-to-front is 'net'.
'sang' with letters rearranged gives 'gans'.
'gans' enclosing 'net' is 'GANNETS'.
(Other definitions for gannets that I've seen before include "people grabbing grub" , "Birds" .)