Ostler occasionally attending shy creature (6)
I believe the answer is:
coyote
'creature' is the definition.
(I have seen 'predatory creature' mean 'coyote' so perhaps 'creature' could also mean 'coyote')
'ostler occasionally attending shy' is the wordplay.
'occasionally' indicates alternate letters.
'attending' is a charade indicator (letters next to each other).
'shy' becomes 'coy' (I've seen this before).
The alternating letters of 'ostler' are 'ote'.
'ote' put after 'coy' is 'COYOTE'.
(Other definitions for coyote that I've seen before include "N. American wild dog" , "Small North American wolf" , "Wild canine" , "predatory creature" , "Wild prairie dog in America" .)