That’s obs of all Vanessa species in CA this year so far on a weekly interval. It should support most of the usual observation URL params, as well as interval (monthly (default) or weekly). If you hover your mouse over the date or hit the spacebar you can step forward and backward in time with the arrow keys. This should be considered experimental and it was mainly made for internal testing, so if you make a URL that renders tons and tons of points and it goes viral, we might have to remove it to survive the traffic / load on our servers, so use it with care. It also does most of the point rendering in your browser, so on some setups it might just lock up the browser. Again, not intended for general use.
There’s also the compare tool, which has all the same caveats but could be used to visualize a pattern like this.