I bought a pair of unsexed ducklings along with 6 pullets last Match. They ended up both being drakes. I have a decent sized pond near their house with plenty of plants; marginal, aquatic and floating, as well as frogs, goldfish and a few mosquito fish. It was very balanced with clear water (plants being the only filter)— it took a couple of years to reach this stable point. I introduced the ducklings to the pond at about 6 weeks of age, they stuck their bills in and waded in the shallow part and then got out. It took another 6 weeks or so before they were comfortable swimming all over the pond. Then I would rarely see them out of the pond. They slowly decimated many of the plants until the water became turbid and green, now they are leaving it alone (mid—October). Now I am trying to add more floating plants and bales of barley straw as well as barley extract, to get it back in balance. In the interim, They have a small pool that I refill daily in their house, that they have been hitting hard for the first time since they were ducklings. I will be curious to learn when they will find it acceptable to go back in the pond, and if going forward they will be more conscious of the impact they make on it. I know they are not as happy with their self imposed hiatus. This fish and frogs seem to be okay in the poor visibility.
Give the ducks time to get comfortable with the pond and then watch for changes and try to correct conditions; they appear to be quite picky. I have a second pond behind the house that they have not discovered, where I grow plants to replace the ones they consume in the main pond. Even with my pond size(around 4000 gallons) these two ducks can make a significant impact on the system: ie more ducks would require much more water area.
