The water surface of the turtle pond is covered with common duckweed (Lemna minor), due to its very fast growth rate.

In order to clear the water, the animal keepers are removing some of the weeds and using them to feed the Nene geese.  Thus, we achieve two goals: enriching the Nene geese's menu and removing excessive organic matter from the pond. As expected from the plant's name – duckweed, our geese see the new food item as a delicacy and meticulously come to the pond each day at precisely the right hour.