If it seems like your trees are swarmed with squirrels right now, it’s because they are.

By the numbers

1 to 1.5Pounds of food eaten per week in warm weather1 to 6Young squirrels per litter; females breed twice per year, and more young tend to be born in years when good weather produces more food1.5 to 8Home range acres6Potential years of life span in the wild, 15 in captivity; high mortality the first yearDNR, Clemson University

It’s the time of year when acorns and other nuts have dropped, and predator hawks are in transition from summer to winter haunts rather than lurking.

So lots of squirrels are scampering, stocking up for the cold months.

A good “mast” crop — basically nut foods — last year has spiked the population somewhat. And more urban squirrels, with more and more bird feeder-y food sources, now tend to hang around in good numbers.

That means more squirrels chewing on ornamental plants, tree bark, house siding or exposed rubber wires. It means more pecan trees getting robbed.

The ubiquitous squirrel “is one of the top nuisance calls we get,” said Billy Dukes, S.C. Department of Natural Resources small-game project supervisor.

Take heart. Even if the toothy, gnawing critters were launching an end-of-time battle, besieged humans might soon have a non-lethal defense — birth control.


Work is under way at Clemson University, where the squirrel-pestered campus is now largely roamed by rodents on The Pill, so to speak.

With the university’s mix of urban environs and forester-furnished landscape trees, the squirrel population is 15 to an acre, about three times more than most other places. And the gnawers have wreaked about $13,000 in damage on at least 100 landscape trees.

Something had to be done, and at a school with an emphasis on animal health, .22 rifles weren’t an option.

Five years ago researchers launched an experiment injecting squirrels with contraceptives, said Greg Yarrow, chairman of the university’s Natural Resources Department.

The idea is to see if the technique can be safely used on squirrels by tree farmers, utilities or other agencies in spots where taking them out, so to speak, isn’t good business.

The injections worked, but the trapping was labor-intensive and the $50-per-squirrel cost was prohibitive. So researchers turned to The Pill.

They now are coating sunflower seeds with DiazaCon, a long-lasting hormone suppressant that already has proven itself on birds from crows to monk parakeets.

“We’re getting good success,” Yarrow said.

Not that homeowners should get their gnawed-over hopes up.

Acquiring DiazaCon would take a restricted-pesticide license or a federal agency.

“I could never see it getting to the point where people could go to their Walmart, Kmart or Lowe’s to get it,” Yarrow said. “At best it might be one tool on down the road (for large-scale operations) where lethal control can’t or won’t be used.”

Reach Bo Petersen at 937-5744, @bopete on Twitter or Bo Petersen Reporting on Facebook.