Chap showing interest at first in bird of prey (5)
I believe the answer is:
ernie
'chap' is the definition.
(man's name)
'interest at first in bird of prey' is the wordplay.
'at first' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'bird of prey' becomes 'erne' (erne is a kind of bird of prey).
The first letter of 'interest' is 'i'.
'i' put within 'erne' is 'ERNIE'.
'showing' acts as a link.
(Other definitions for ernie that I've seen before include "Premium Bond picker" , "___ Wise, d. 1999" , "Premium Bond selecting machine" , "Eric's other half" , "Name given to selector" .)