In the way that you call groups of geese a ‘gaggle’ and a group of lions is a ‘pride’ you can call a group of ducks a ‘flock,’ ‘raft,’ ‘team,’ ‘padding,’ ‘badding’, or ‘brace.’
A flock of ducks that lived on the roof of a hotel in Memphis, Tennessee, used to take the elevator to the ground floor when they wished to go anywhere.