https://old.reddit.com/r/aww/comments/9728ab/my_rescued_duck_petunia_greeting_me_after_a_long/ but I don't recall ducks wagging their tails like a dog!
@Neville Telen We have many wild ducks inhabiting the Colorado River area, and many wiggle their tails often. My wife claims the ones having upturned tail feathers are females. Frank