He at first attributed the eradication to quarterly San Mateo County Health inspection reports that said squirrels were burrowing through the landfill cap and dragging garbage up to the surface, where the trash could blow into the waterways. "The city got comments on its quarterly reports that squirrel activity was very high and squirrels had actually penetrated the cap," Mr. Steffens said.
However, none of the county inspection reports stated that was the case.
"The main concern with the ground squirrels, or any other burrowing animal, is that their burrows can damage the landfill cap," explained Dean Peterson, the county's director of environmental health. "Caps are designed and installed to limit the amount of water entering a landfill and to control gas production — so an uncontrolled population of burrowing animals could eventually devastate the cap."
If methane gas escapes from the cap, it creates a fire hazard, according to experts.
"We have no evidence of the squirrels actually dragging trash to the surface at the Marsh Road sites," Mr. Peterson said.
So the squirrels may indeed have posed a problem — the county inspection reports do mention increased activity — but how did the city decide that litter at the park was the squirrels' fault?
"Well, we know because we followed up on it," Mr. Steffens said. "When the problem was identified, city staff did its own investigation, and said, 'OK, what are we going to about this'?"
He said he didn't know how many burrows were baited with poison, or how many squirrels died as a result. Neither did a representative from Animal Damage Management, who said the technician who carried out the contract was on vacation.
This story contains 342 words.
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