Loco dabbler? (7)
I believe the answer is:
mallard
I believe this is a double definition.
'loco' is the first definition.
(Mallard is a type of locomotive)
'dabbler?' is the second definition.
(mallard ducks dabble in order to feed)
(Other definitions for mallard that I've seen before include "Oldest breed of duck" , "Type of duck - world speed record holding steam engine (1938)" , "Common wild duck" , "The famous steam train" , "Engine holding the world speed record for a steam locomotive, set at 123mph in 1938" .)