### Clue: Pub's standard drink leads to trouble, ducks (7)
### Answer: PINTAIL 
 ### Explanation: Definition: ducks
 PINT(the standard unit measure of beer or cider served in the UK and Ireland, even post-metrication) + AIL(to trouble, as in "what ails you?").
Answer: Plural for the greyish-brown ducks with pointed tails of the Northern Hemisphere.