What were those tiny winged insects in Kensington, North Berkeley after recent rains?

DR. JOAN: This morning, we witnessed an unusual occurrence. Hundreds of small flying insects began to swarm as the sun warmed the ground after our rain.

They appeared to be coming from the ground, but I couldn’t tell where. We have decomposed granite in the courtyard where they first appeared, but no sign of the small holes. They measure about 12 to 5/8-inch in length and have two sets of glasslike wings with a wingspread of about 1 inch.

We needed to run an errand in Berkeley, and they appeared all over North Berkeley. They suddenly vanished after about two hours.

Shelley Dommer from Kensington

DR. SHELLEY: What you described is common in the autumn after a rain shower. Subterranean termites are the winged insects. Termites are common in California, and we have both dry wood and those that live underground. Mud tunnels they build to reach wood above ground are one sign that you have a colony living beneath you.

The termites are sexually mature, and they leave the colony after the first fall rain to establish new colonies and begin reproducing. Many are eaten by birds and other insectivorous animals, but not all.

DR. JOAN: Anna’s hummingbirds, mostly males, visit our feeder on a regular basis. They typically feed one at a time before being chased away by another.

There were two males at the feeder this morning, one eating and the other standing guard. The sentinel would scan the area and never eat. The one who was eating flew away, and another male came in from the opposite direction, which the sentinel chased away.

Do you believe the sentinel is always chasing the others away, or do you believe the chaser varies and they all just chase each other? Why do you think he was standing guard while the one eating ate?

— San Ramon resident John Tessman

DR. JOHN: I’m not sure why the first hummer let the other drink while chasing away the second. Perhaps the first one gave the sentinel a few dollars and the second refused to pay. Hummers are adorable and beautiful, but they can also be feathered gangsters.

This feeder has most likely been claimed by the sentinel hummingbird. If so, he stays near it, perhaps hidden in a tree or shrub, ensuring that only approved guests are allowed in. Bullies can be replaced by bigger bullies, but hummers don’t share jobs.

Krane Pond update

In the five weeks since we launched a fundraising campaign to save and protect Krane Pond, an important wildlife water source, 234 readers have donated $55,775 to Save Mount Diablo. The fund is now at $443,391, or 89 percent of its $500,000 goal.

More importantly, the success has prompted longtime Save Mount Diablo supporters Philip Matthews and Dian Heisey to match donations up to $20,000.

Donations can be mailed to Save Mount Diablo at 201 N. Civic Drive, Suite 190, Walnut Creek, CA 94596, or made online at https://savemountdiablo.org/donate. Please specify that your donation is for Krane Pond.