Half of street's enthralled by wheeling glossy birds (8)
I believe the answer is:
kestrels
'birds' is the definition.
(kestrel is a kind of bird)
'half of street's enthralled by wheeling glossy' is the wordplay.
'half of' suggests halving the letters.
'enthralled by' indicates putting letters inside ('enthral' can mean 'capture').
'wheeling' is a reversal indicator (letters wheel back).
'glossy' becomes 'sleek' (synonyms).
'sleek' in reverse letter order is 'keels'.
'street' halved is 'str'.
'str' inserted within 'keels' is 'KESTRELS'.
(Other definitions for kestrels that I've seen before include "Elk rests awkwardly on the birds" , "Birds of prey" , "Small falcons" .)