Did strange insect activity foreshadow recent quake?

DEAR JOAN >> Our home in the El Dorado Park neighborhood of Walnut Creek has a small tributary of Grayson Creek running through the southeast border of the property.

We are also less than a mile from the epicenter of the recent 4.5 earthquake in Pleasant Hill.

Minutes before the earthquake at 10:19 p.m., our security camera caught some raccoons running along the creek, and shortly after that, insects started rising up from the ground. Lots and lots of insects.

Can you tell us what the insects are or anything about them?

By the way, we also have bats from time to time that we’ve seen on the camera.

I guess we now know what the bats are hunting for. — Ann and Paul, Walnut Creek

DEAR ANN AND PAUL >> First things first, identifying those insects that look like flashes of light darting up from the ground.

I shared your video — which readers can see at bayareane.ws/WildlifeVideo — with Steve Schutz, scientific programs manager for the Contra Costa County Mosquito and Vector Control District, and he suspects they are mayflies.

The mayflies hang out near water, and their presence, which may come as a relief to you, are an indication the creek is clean and healthy.

As to why the raccoons ran and the insects flew, we don’t really know for certain.

Tons of anecdotal evidence support the theory that some creatures can sense a pending earthquake, but we don’t have any hard scientific proof.

According to the U.S. Geological Survey, the earliest reference to unusual animal behavior before a significant earthquake is 373 B.C. in Greece.

Reports of the time said that “rats, weasels, snakes and centipedes left their homes and headed for safety several days before a destructive earthquake.”

The theory has been tested in China, spurred several decades ago when animals began acting oddly, prompting many people to sleep outside their homes, an act that saved many lives when an earthquake soon hit.

However, the next large quake to hit provided no early warning from animals, and thousands of Chinese people died.

The event captured in your video occurred about 4 minutes before the first quake of any strength, a 2.5, was felt in Pleasant Hill, and roughly 15 minutes before the larger one.

The raccoons might have sensed something coming, or perhaps they were startled by the lights coming on.

The insects could then have been attracted to the light.

It’s very interesting, though, and I’d love to hear more stories about creatures sensing earthquakes.

My dog just sleeps through them.

DEAR JOAN >> After reading your recent column about bird nest material, I am wondering if it’s OK to leave out dryer lint for the birds? Would they use it? — Marcia Citta, Saratoga

DEAR MARCIA >> They would use it, but they shouldn’t.

There’s no binding structure to the dryer lint and, while it looks comfy and cozy, it dissolves when it gets wet, which can then threaten the integrity of the nest.

Some people also say that the chemicals used in dryer sheets or softeners aren’t good for the birds.