You're quite right - they are charming.
Unfortunately there's loads(!) and they're all at the top of the room. I have high ceilings. They're all congregating at the top of the window but above the open part so I need to get them to move away. I can't open the window and hope they find their way out eventually as loads more will come in. Also, my blind will obstruct efforts to move them on.
I fear they will expire fairly rapidly as it's a sunny day and is quite hot up against the window.