Attention Ribbited on Invaders : Wildlife: Some residents are perturbed, while kids leap with glee over an amphibian invasion in upscale North City West.

The sidewalks, parks and yards of Del Mar Highlands are hopping with an invasion of thousands of tiny toads that appeared virtually overnight after the Memorial Day rains.

“I counted 72 of them in 15 minutes while I was out walking my dogs the other evening,” Ruby Rodriguez said. “And I only counted the ones that hopped up, not the ones that were sitting there.”

The toad infestation has provided a new pastime for neighborhood youngsters, who vie to see how many they can squash with their skateboards. They are less fun for joggers, who must do some broken-field running to avoid them.

The tiny amphibians, khaki-colored with spots and ranging from nickel-size to quarter-size, are Western toads, or more scientifically, Bufo boreas , said Greg Pregill, herpetologist with the San Diego Museum of Natural History.

Although the toads are common to this region, the hatch or “bloom” in Del Mar Highlands, a bluff-top neighborhood in the North City West planned community, is unusual because few hatchings have been reported this year, he said.

The toadlets once were tadpoles, swimming in a pond or drainage ditch until they developed into the Plague of Del Mar Highlands--able to live away from water but still attracted to the sprinkler-fed landscaping of the hilltop community.

“Thank heavens! I thought I was the only one who had seen them,” one resident of the Highlands said when queried about the toad population explosion in the neighborhood. “I went out in the back yard the other night, and it was alive with them. I thought I was seeing things.” She asked that her name not be used, explaining that “it’s not the sort of thing you want to be associated with.”

Geraldine Munter remembers back two years or so when “there were frogs all over the place,” but said that the invasion didn’t occur last year, at least not on Lady Hill Road, where she and her husband live. “My cats are having a ball, chasing them all over the place,” she said. “I can’t imagine where they came from, unless someone brought them in. They just appeared all of a sudden after that big rain we had.”

She’s a bit concerned that the toads may not be quite the thing for her cats to dine on.

“I’ve heard that some kinds have a poison in their systems as a protective thing, so they won’t be eaten,” Munter said, but she acknowledged that her cats did not seem to be suffering from indigestion. “I suppose that cats are smart enough not to eat them if they are poisonous.”

Pregill agreed that the toads would hardly replace Nine Lives as a prime feline diet, since they do have a low-grade poison in sacs behind their eyes that makes them taste awful and prevents predators from gorging on them. But the toads are otherwise completely harmless, he said, and “don’t vocalize at all,” so there should be no midnight serenades in the neighborhood.

They eat insects, including mosquitoes, growing to 3 to 4 inches long, and make good show-and-tell subjects for elementary school classes.

With the four-year drought drying up normal marshy areas and with rampant development gobbling up most of the toads’ normal habitat, North County suburbia is probably the best housing bet for a Bufo boreas , Pregill said.

Keith MacBarron, a vector ecologist with the county Department of Health Services, said the invasion is perhaps a nuisance, but not a hazard.

“It would be stretching it a bit to say they were vectors,” MacBarron said, explaining that vectors are creatures posing a health threat to humans. Mosquitoes and rats qualify. Toads don’t.

Pregill predicted that the problem will take care of itself. Within a few dry days, the toads will go to ground, burrowing down into soil to go dormant for the summer, until cooler weather and winter rains arrive.

Still, Rodriguez said, “it’s sort of creepy” to look out the patio door and see several of the minuscule amphibians, their faces pressed against the glass, looking in like peeping Toms.

“They are sort of cute now,” she said, “but there are an awful lot of them. I just hope that they don’t grow up. I couldn’t stand that.”