Big bird that is shot less than a birdie (5)
I believe the answer is:
eagle
This clue is a quadruple definition!!
'big bird' is the first definition.
(I've seen this in another clue)
'that is shot' is the second definition.
(thesaurus)
'less' is the third definition.
The answer and definition can be both quantities as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'than' is a link.
'a birdie' is the fourth definition.
(thesaurus)
Can you help me to learn more?
(Other definitions for eagle that I've seen before include "Bird with hooked bill and long broad wings" , "Keen-eyed bird" , "Score of two strokes under par for a golf hole" , "Fine achievement on course" , "Bird of prey; former children's comic" .)