Squirrels keep dying on Mount Graham
By Tom Jackson King, Managing Editor

The fall 2001 count of Mount Graham red squirrels is now just 247 -- a massive drop from a peak number of 549 in fall 1998 and the lowest count of squirrels since 1993, according to a report released by AGF and the U.S. Forest Service.

The die-off of squirrels is part of a two-year trend that Forest Service biologists blame on the death of more than 16,000 acres of spruce trees. The seeds in spruce cones are the preferred food resource for the small, shy squirrels.

A controversial aspect of the die-off in the endangered squirrel subspecies is their presence overlaps with the eight acres occupied by the Mount Graham International Observatory atop Mt. Graham, a presence that some critics say has worsened the survival prospects of the squirrel. Others say the die-off is a natural part of nature's ebb and flow of trees, insects, animals and weather.

Bill Van Pelt, Arizona Game and Fish nongame birds and mammals program manager, said the Oct. 1-4 survey by 25 biologists from AGF, USFWS, the Coronado National Forest and the U.S. Fish and Wildlife Service, found fewer squirrel middens in each of the forest zones where squirrel presence is counted by tracking the number of cone scale middens that have signs of fresh activity.

"About 20 percent of the middens surveyed in the spruce-fir (zone), 34 percent in mixed conifer forest, and 33 percent in the transition forest vegetation types showed signs of recent use by Mount Graham red squirrel," Van Pelt said.

Since squirrels that were live-trapped in the past have died, forest biologists have relied on an indirect counting method to estimate the number of squirrels now living on the Pinaleno Mountain range.

"We actually visit randomly chosen middens, or cone scale piles," Tim Snow of AGF said. "We look for recent activity such as new cone scales, fresh digging and stored cones."

Genice Froehlich, field biologist for the Coronado National Forest office in Safford, has been warning for more than two years that insect devastation of spruce trees on Mount Graham would result in a large decline in living Mount Graham red squirrels.

"The main thing I want to reiterate is this infestation is far from over. Maybe 16,000 trees were killed last year. It could be the same number this year," she said in July.

Froehlich said treating individual trees for insect infestation is pointless. "The infestation is so widespread, it's pretty useless to do any forest-wide treatment. And stepping up our controlled burning in the spruce and fir forest would not help. It will kill all the living trees if we burn in the spruce and fir," she said.

Dr. Robin Silver of the Center for Biological Diversity in Tucson blames the population drop on the construction of telescopes on the mountain by the University of Arizona, with a resulting loss of squirrel habitat.

"The squirrels are endangered because of piecemeal loss of habitat. The controllable piecemeal loss to date is the loss of 1,000 trees and interference with squirrel migration by astronomers. Also, fire suppression activities are aimed solely at saving Columbine Cabin. They jeopardize the squirrel," Silver said. He then demanded the removal of the three telescopes now atop Mt. Graham.

Buddy Powell of Steward Observatory, which operates the three telescopes now on top of Mount Graham, said the astronomers aren't to blame for squirrel deaths.

"We've been on the mountain since 1989 and, during the heavy construction, squirrel population went from about 125 to 550. We know well over 1,000 acres are affected by bug infestation. From the LBT, we see massive devastation of the spruce and fir. The bottom line is, if 1,000 acres were killed by bugs, how much impact did eight acres have?" Powell said.

Jeff Humphrey, a spokesman for U.S. Fish and Wildlife, said the large die-off of squirrels as insects infest their food trees may be a part of nature's normal cycle.

"There's evidence that die-offs like this have occurred over the millennia and they have probably had a role in the natural cycle on Mount Graham. We need to assess if this current cycle is something the (squirrel) species can tolerate, like it probably has in the past," he said.

Squirrel numbers have been counted since spring 1986. The lowest number was about 125. The highest number counted was 549 squirrels in fall 1998. This is the third major rise and drop episode in squirrel population since 1986. A review of data provided by USFS shows that even with the steep population drops, squirrel numbers ended up higher in each successive drop than in the previous drop -- except for this fall's count, which is slightly lower than the spring 1995 count.

The next count of squirrels will come in spring 2002. It may show whether the population drop of the last two years is continuing or whether red squirrel numbers have leveled off as the animals move sideways into other forest zones less affected by insect infestation.

Copyright 2001 Eastern Arizona Courier