Twice a day, you can see a parade of ducks in Stellenbosch, South Africa, when hundreds of ducks go to work at 9:45 AM, and when they come home at 3:45 PM. The Vergenoegd Wine Estate keeps 700-800 ducks as pest control specialists for the vines.
The ducks eat slugs, bugs, and other pests that threaten the vineyards. They have been employed since 1984 (not the same ducks), and have proven invaluable. Since no chemical pesticides are needed, the vineyard has a WWF biodiversity certificate. -via the Presurfer