The cat jumped on a big bird on the axe (8)
I believe the answer is:
tomahawk
'the axe' is the definition.
(I've seen this before)
'the cat jumped on a big bird' is the wordplay.
'the cat' becomes 'tom' (a tom is a male cat).
'jumped' says the letters should be written in reverse (I've seen 'jumping' mean this (in a down clue, letters jump up)).
'on' indicates putting letters inside (as in clothing 'on' a person).
'a big' becomes 'wah' (I can't explain this - if you can you should believe this answer much more).
'bird' becomes 'ka'.
'wah' going inside 'ka' is 'kwaha'.
'kwaha' backwards is 'ahawk'.
'tom'+'ahawk'='TOMAHAWK'
'on' acts as a link.
Can you help me to learn more?
(Other definitions for tomahawk that I've seen before include "North American Indian hatchet" , "intended to make a kill" , "Light native axe" , "Native American fighting axe" , "American Indian axe" .)