A dog to the Spanish; a bird to us (8)
I believe the answer is:
cockerel
'a bird to us' is the definition.
I can't judge whether this definition defines the answer.
'a dog to the spanish' is the wordplay.
'a dog' becomes 'cocker' (cocker is a kind of dog).
'to the spanish' becomes 'el' ('the' in Spanish).
'cocker'+'el'='COCKEREL'
Can you help me to learn more?
(Other definitions for cockerel that I've seen before include "He's liable to crow" , "Young rooster" , "Young domestic male fowl" , "Farm awakener" , "Given bird" .)