Stadtmauerente?

Here’s something you don’t see every day.  This is the medieval city wall of the city of Konstanz, also known as the Stadtmauer (the wall, not the city):

That’s not the amazing bit.  The truly amazing bit is way up on top: a female mallard duck that looks like she is roosting there:

Even if she is not roosting there, it is still an amazing site to see a duck perched high on a monument, like a stork or a pigeon!