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' says the answer is hidden in the clue.
'TEA' is hidden in the letters of 'what wheatear'.
'to' is the 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" .)