Germany's top beer intoxicated bird (5)
I believe the answer is:
grebe
'bird' is the definition.
(type of bird)
'germany's top beer intoxicated' is the wordplay.
'top' says to take the initial letters (in a down clue, the first letter is top).
'intoxicated' indicates anagramming the letters.
The initial letter of 'germanys' is 'g'.
'beer' is an anagram of 'rebe'.
'g'+'rebe'='GREBE'
(Other definitions for grebe that I've seen before include "Freshwater diving bird" , "Duck-sized water-bird" , "Diving water bird" , "I'll dive in" , "Diving waterbird" .)