Cookie Policy
last updated 22 august 2026
Necessary
If you sign in, one cookie keeps you signed in. Without it there is no way to know which butterflies are yours. It cannot be turned off while you are signed in, and it goes away when you sign out. A second cookie remembers that a guest has let a butterfly go today, which is how the one-a-day limit works. It holds a date and nothing else, and it expires by itself. A third one appears only when you follow a password reset link, and only for a quarter of an hour: it carries the token from that link so the token never has to sit in the address bar, and it is dropped as soon as the new password is set. None of the three can be read by scripts running in the page.
The bot check
Before a message from the contact form reaches us, Cloudflare checks that a person filled the form in. That check runs in the page and may keep a token of its own in your browser to tell people apart from scripts. It is on the contact page and nowhere else, and it is not used to follow you between sites.
Preferences
Two things are kept in your browser and never sent to us: a butterfly you have started but not released yet, so that reloading the page does not lose the colours and the name you chose, and the fact that you have dismissed the notice shown when the meadow cannot be drawn. Both live in the tab and disappear when you close it. Nothing else is remembered — the camera position and everything else are recalculated each time the page loads.
Measurement
We do not use advertising or cross-site tracking cookies. If we ever add a way of counting visits, it will be one that does not identify you, and this section will say so before it is turned on.