What the wheatear has to drink (3)
I believe the answer is:
tea
'drink' is the definition.
(tea is a drink)
'what the wheatear has' is the wordplay.
'has' indicates the answer is hidden within the clue.
'TEA' is hidden in the letters of 'what wheatear'.
'to' acts as a link.
(Other definitions for tea that I've seen before include "Refreshment" , "Dried leaf infusion" , "Infused leaves" , "A light meal - eat up" , "Sort of garden, chest or service" .)