Residents of the San Francisco area saw a curious sight in the sky Wednesday: strands of white webbing floating down to the ground, carrying baby spiders inside them.

When baby spiders are born, they produce silk webbing that is light enough to be picked up by the wind, allowing them to float away and land elsewhere, colonizing new habitats.

To find out where to go, spiders pick up on electric currents when they are traveling in the wind, or “ballooning,” Fred Larabee, an entomologist at San Jose State University, told KNTV.

“The wind is definitely dragging them and affects the directionality of where they’re going. But then also, they absolutely can sense these electric fields. They have very specialized structures on their legs that are attuned to these electric fields; they respond to them,” he said.

While the baby spiders ride individual threads, the threads often clump, after which the spiders leave the webbing and go out into their new habitats.

Appropriately for the season, the clumps of real webbing look very similar to the fake webbing used in Halloween decorations.

“They look almost like the fake spider web stuff that you buy at the Halloween store. It was very silky and sticky,” Bay Area resident Brook Shadwell told the San Francisco Chronicle.

• Brad Matthews can be reached at bmatthews@washingtontimes.com.