Photo by Wolfgang Kippes
The caption called this a sperlingskauz, which was translated to "Sparrow Owl."
I'd never heard of a Sparrow Owl, but the EPO has a scientific name that is Latin for "Sparrow Owl" that I will assume is how it got its German name.
Ah, I was finally able to figure out the "joke," as I only got the "flat" earlier as I didn't know "huhu." I had just searched for "eulenwitz," and this thing popped up a million times. I knew "uhu" but I was too tired yet to notice the extra H to figure it was a pun. I knew one of you would lead me to the answer though!
For everyone not in on it:
Was sitzt auf einem Baum und winkt? — Ein "Huhu“! What is sitting on a tree and waving? – A “Huhu”!
Explanation: in German, “huhu” is a greeting, while “Uhu” signifies an “owl”
From The ~~Funniest~~ One and Only Multi-Language Jokebook
It's broken
Edit: Shows on web, not in app
:( And here I hoped that changing the instance would help
It can also be found here: https://kekememes.de/picture/der-praktikant-sollte-eine-kiste-uhu-bestellen-xva1Xf4f8