Flocks of white, black and brown ducks hunt for snails and bugs as they patrol the grapevines at a vineyard in South Africa’s winemaking town of Stellenbosch, helping the owners steer clear of pesticides and synthetic fertilizers. The flock of almost 500 ducks serve as both natural pest control and entertainment for the wine-quaffing tourists who visit the vineyards. “We call them the soldiers of the vineyards,” the managing director of the estate, Corius Visser, told Reuters. Following their leader, the ducks march in convoy through the vines looking for pests. The ducks follow a daily routine: In the morning, they go to the vineyards to prevent crop damage, and in the evening they return to their paddocks to peck at pellets of nutritious bird food.