Hogwarts castle question re 3 tiny towers

[SmallWorld71]

What are the three small towers that stick out from one of the larger towers on the castle?

We noticed them this summer at WWOHP but then forgot about them. DS11 is working on the Hogwarts LEGO set now and there they are again - sticking out of the owlery on the playset. I feel like I saw the answer here months ago, but I can't remember what it is.

Thanks!

 

[damo]

It is the Headmaster's tower.

 

[SmallWorld71]

It is the Headmaster's tower.

Thanks!