The six swans are still on South Platte Park Reservoir (and probably have been all day). They are out of view from the dam, however you can see them from the business at 7926 Platte Canyon Drive. Drive to the end of the parking lot and look east through the wrought iron gate.
The Tundra Swan is currently on the very south edge of Blackrock Lake. This is the small Lake just east of South Platte Park Reservoir.