Butterfly logic

I am a beautiful butterfly.
I will land on the windowsill when you least expect it, and wait for you to rush to fetch your camera.
I will wait, basking in the sun, until you come back and open the window.
I will watch you hang out of the window (notice, I chose upstairs, rather than downstairs).
Then I will shift along to the next window.
Now you're in the bathroom, looking even sillier as you hang outside with your camera.
I won't keep still. The sun is so nice I need to move about to cover every little bit of my lovely colourful body.
You are trying to take my photograph.
I am laughing at you (they are bound to be blurry).
Now I'm going to fly away. Bye.