See the red stuff on that rock? That’s a swarm of ladybugs. A few weekends ago some friends and I paid a visit to their winter home on Mount Diablo, near Clayton, California. It was almost scary how many there were. Here’s a closeup.

It seems they live down by the coast in the warm months, then move inland into the mountains when it gets cold. They can’t fly unless it’s warmer than 55 degrees! They also have a life cycle of only four to six weeks, so how do they know to go back to the same place every year? We found them along the Falls Trail loop and it looks like they go to Redwood Regional Park too. One more fun fact: It takes 24 hours for an adult to get its spots.

And for the land-use lovers out there:

A nice shot of the Clayton Quarry, a source of diabase, a hard rock destined by law for local construction uses that have included the rail beds of the Bay Area Rapid Transit system and Interstates 580 and 680. Here’s more info on its use and history.