Rustic husband deserts bird (7)
I believe the answer is:
peasant
'rustic' is the definition.
(I know that peasant is a type of rustic)
'husband deserts bird' is the wordplay.
'husband deserts' becomes 'peas' (I am not sure about this - if you are sure you should believe this answer much more).
'bird' becomes 'ant bird' (ant bird is a kind of bird).
'peas'+'ant'='PEASANT'
Can you help me to learn more?
(Other definitions for peasant that I've seen before include "rude fellow" , "Rural person of low class" , "Provincial" , "Rural labourer" , "Poor smallholder" .)