This image was the result experimenting with the nice sapling tree gen addon. I got a deeper look to the particle system doing this as well.
The whole scene consists of around 500M triangles (including particles), but blender handles this very smart.
All things except the ducks are created by myself. Textures mainly from Texture Haven and textures.com, duck models from free3d.com (user printable_models).
I hope you enjoy it :)