Stellenbosch — The quacking is soft at first amid the vineyards that roll for miles in this South African wine-making town.But then the duck handlers whistle and wave their white flags, and the noise reaches a crescendo. All 1 071 ducks huddle at the gate that separates them from the vineyards.It's time to go to work, and the daily duck parade is about to start.This wine farm is winning praise from environmentalists for using Indian runner ducks instead of chemicals to eradicate pests like snails and bugs from its vineyards.The duck parade is also a colourful affair that attracts tourists.John Faure, whose family had owned the Vergenoegd wine estate since 1820, imported six Indian runner ducks in 1984 to control pests in his garden. He then started breeding them and, as the workforce grew, so did their job description.The estate, which was recently sold to a German owner, continues to use the ducks for pest control although it is much more expensive than pesticides, said the vineyard's social media manager David Badenhorst. The ducks cost an average of $2 300, while more conventional methods would cost that amount per year, he said. Using the ducks is more sustainable, Badenhorst said."If you use conventional pest control, those chemicals are absorbed into the soil, which affects the growth of the vines and kills insects," he said. "Our ducks go into the vineyards and they eat the snails and snail eggs while fertilising the soil."