You are warned! The owl is puking in this video! People, who will write in the comments "Eeew, I was eating!" can only blame themselves.
But really, the process shown in the video is not vomiting, but a natural and very important stage in a birds digestion. Almost all birds that eat arthropods and any other type of food that contains indigestible fragments. For instance, a crow can make a pellet out of ground fresh carrots.
It's essential for birds of prey to make pellets. Without this their digestion will develop deep malfunctions that will lead in time to critical consequences and eventually to the birds death.
Yoll is making a pellet once daily, several hours after a meal. This means that her stomach is empty and she's ready for the next meal.
Usually birds refuse food if they haven't yet emptied their stomach.
Boreal Owl Chuchundry takes the offered food, but holds it in his paws until the pellet comes out and only then starts eating.
One of the main reasons birds of prey cannot be fed exclusively with raw meat is the impossibility of making a pellet out of it.