If Westerners cannot thank Christopher Columbus for the glut of free-roaming horses in these parts, they surely can thank those who followed him. It was the Spaniards, not Mother Nature, who brought the beasts to North America and then turned them loose to fend for themselves, and it has been inaction that guaranteed they’d be the problem they have become in recent years.

That’s something to keep in mind when reading news stories about wild horses and burros, most recently one this week about a recommendation that the federal Bureau of Land Management begin sterilizing some mares.

The agency has to do something. Under the Free-Roaming Wild Horse and Burro Act of 1971, the animals no longer may be rounded up and sold for pet food. Instead, they must be allowed to roam free or, when there are too many, adopted under strict guidelines. The law applies to all wild horses and burros on federal land, more than 37,000 last year.

What makes the horses such a problem is this. They’re not native, and they have no natural predators in the intermountain West. Their herds naturally grow by as much as 20 percent a year and as unregulated grazers, they do terrible damage to the plants that keep native animals alive.

To keep their numbers even marginally in check, the BLM rounds up thousands every year and tries to find homes for them.

It isn’t easy.

Nationwide, nearly 9,000 were rounded up in 2011, according to BLM statistics; just under 3,000 were adopted. The rest bide their time in holding facilities near Burns and elsewhere. The ratio of adoptions to captives is so bad, in fact, that some 60 percent of the BLM’s wild horse and burro budget is spent to house and feed the animals.

If logic, not emotion, guided the wild horse program, the animals would once again be treated as the invasive species they are in the intermountain West, rounded up and disposed of. It would surely be cheaper and, if done carefully, humane.

Not that we expect such a lightning bolt of logic to strike Congress anytime soon. Until it does, sterilization may be the best alternative.