The Queen entertained by regularly shooing a bird (5)
I believe the answer is:
heron
'a bird' is the definition.
(I know that heron is a type of bird)
'the queen entertained by regularly shooing' is the wordplay.
'the queen' becomes 'ER' (Elizabeth Regina).
'entertained by' indicates putting letters inside (inserted letters are hosted or entertained).
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternating letters of 'shooing' are 'hon'.
'er' placed within 'hon' is 'HERON'.
(Other definitions for heron that I've seen before include "Long-legged long-necked wading bird" , "Rhone (anag) - bird" , "One bird" , "Wading bird with long neck and legs" , "Big bird" .)