..... to notice amphibian .... (4)
I believe the answer is:
toad
'amphibian' is the definition.
(toad is a kind of amphibian)
'to notice' is the wordplay.
'notice' becomes 'ad' (short for advert).
'to'+'ad'='TOAD'
(Other definitions for toad that I've seen before include "Dangerous driver" , "not found in Ireland" , "Hateful person; animal" , "Ugly creature, jewel in head (AYLI)" , "Warty amphibian" .)