Ground squirrels are being killed again
Publication Date: Friday Mar 21, 1997

STANFORD: Ground squirrels are being killed again

Seeking to preserve trees, Stanford resumes program with new poison

Stanford University was criticized last September for its program of killing ground squirrels in the arboretum by poisoning them. The poison used then, an anti-coalugent, caused the ground squirrels to go into convulsions and die unpleasant deaths.

Stanford has now resumed killing ground squirrels, but it is using what it calls a more "humane" and very quick method by inserting poison gas into their burrows.

Stanford officials are convinced the eradication program is necessary to protect the towering palm trees that line Palm Drive. The ground squirrels are eating into the trees, causing potential health problems for the trees and also weakening them structurally, said Chris Christofferson, director of facilities management at Stanford.

"I had to be convinced that the damage they were doing was worth an eradication program," Christofferson said. So his staff brought him photographs of damaged palm trees, some of which had been bored right through by the ground squirrels.

Palo Alto resident Dena Mossar, who walks her dogs in the Stanford arboretum nearly every day, noticed last weekend that she didn't see any ground squirrels. "And there were no great blue herons, which hunt the squirrels," she added.

Mossar said elimination of the ground squirrels affects other animals above it and below it in the food chain. "Ground squirrels are a native species," Mossar said. "They're part of the deal."

Instead of leaving out baited traps for the ground squirrels, the new program is focused only in areas where actual damage has occurred, Christofferson said.

The poison gas "is significantly more humane" because the squirrels die very quickly, he said. "It's very quick acting," he said.

During the former eradication program, some residents had expressed concerns that the poison in the dead ground squirrels was working its way up the food chain by being ingested by raptors, like hawks and owls. But Christofferson said the university found no evidence of that.

A bigger factor in the switch, Christofferson said, was that the poisoned bait "was pretty unpleasant for the squirrels."

One factor in the abundant ground squirrel population is that they have few natural predators in the area.

--Don Kazak

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