Sally, say, on bird migrating west (6)
I believe the answer is:
legume
'sally' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'on bird migrating west' is the wordplay.
I cannot really see how this works, but
'on' could be 'leg' (cricket term, fielding positions) and 'leg' is located in the answer.
This explanation may well be incorrect...
'say' is the link.
Can you help me to learn more?
(Other definitions for legume that I've seen before include "A fruit that bears its seed in pods" , "Bean, pea etc" , "Plant that bears its seeds in a pod" , "pulse" , "Eg, pea, bean plant" .)