The wagtail? (4,3)
I believe the answer is:
bird dog
'the wagtail?' is the definition.
The definition and answer can be both animals as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'wagtail?' is the wordplay.
I cannot really understand how this works, but
'wagtail?' could be 'bird' (wagtail is a kind of bird) and 'bird' is located in the answer.
The remaining letters 'dog' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for bird dog that I've seen before include "American retriever" , "Retriever (in US)" , "animal" , "American talent scout" .)