A few nights ago at 9 p.m., the thermometer on the back porch read a springlike 60 degrees as I stepped out to listen for a few minutes. No owls on this night, but soon I heard a "yip." And then another. The local family group of coyotes was passing thorough the valley below.

For several years, I've been hearing coyotes occasionally, but I've still never seen one. And that's a big reason they have become so increasingly common and widespread. They are shy and ever alert.

Some people attribute the coyote's success to intelligence. I think it's natural selection at work.

I often hear readers blame state wildlife agencies for increasing coyote populations. They insist that biologists "release coyotes to control deer populations." It's a classic rural legend, and it is not true.

Coyotes are native to Western prairie states. They began expanding their range eastward at least 80 years ago. In "The Clever Coyote," first published in 1951, authors Stanley Young and Hartley Jackson list West Virginia, Pennsylvania, Ohio, New York and Michigan among 21 Eastern states where coyotes had been living for at least 20 years. Today they live in every state east of the Mississippi River.

It's easy to attribute the coyote's success to innate intelligence and guile. Certainly coyotes are smart, but more important they are adaptable opportunists. Individuals that survive and breed are the ones that avoid traps and stay just out of rifle range. And most important, when poisoned, trapped, and hunted mercilessly by predator control agents out west, they responded by making more coyotes.

When coyote populations decline, more females breed and they produce larger litters. So when Western sheep ranchers persecuted coyotes back in the 1950s and 1960s, coyote reproductive rates increased. Females in controlled populations averaged seven pups per litter compared to four in uncontrolled populations. The result is that intense efforts to kill coyotes rarely result in long-term control. That remains true today, and it has just as much to do with fertility as intelligence.

Consider Pennsylvania, where there is no closed season and no bag limit on coyotes. The coyote harvest jumped from fewer than 2,000 in 1990 to more than 20,000 in 2006. And still they thrive in every county.

One reason coyotes seem unfazed by control efforts is that they adapt well to suburbia. They eat almost anything -- rodents, rabbits, pet food, poultry, garbage, fruit, etc. And by living close to people, coyotes gain protection and learn to eat a new easy-to-kill prey -- pets. This is just another reason to keep cats and small dogs indoors.

The thought of coyotes killing pets sends a chill down my spine. My 14-pound lap dog would be a tasty treat for a 35-pound coyote. So each night before going to bed, I watch from the porch as he does his business.

I suspect most folks don't think about coyotes until a pet disappears. Out of sight, out of mind. Some lose a dog or cat before they even realize coyotes are present. Coyotes certainly explain at least some of the missing dog or cat signs posted on bulletin boards at local grocery stores.

In nature, away from people, coyotes can help stabilize animal communities. Biologists in North Dakota have found that the presence of coyotes actually increases the nesting success of ducks.

  The northern prairies of North America produce most of the continent's waterfowl. Unfortunately predation, mostly by red foxes, keeps nest success low. Where red foxes were common, duck nest success was only 17 percent. Where coyotes were common, foxes were scarce, and duck nest success almost doubled to 32 percent.

Just as wolves do not tolerate coyotes, coyotes do not tolerate foxes. Whether they drive them out of an area or actually kill them is unclear. Think of it as the canine pecking order. The practical result is that where coyotes occurred, fox populations declined. So when coyotes dominate an area, duck nest success booms.

The lesson is that nature is more complex than a superficial glimpse might suggest. Predators, though often viewed as bloodthirsty killers, actually add structure and diversity to interconnected animal communities.

Send questions and comments to Dr. Scott Shalaway, 2222 Fish Ridge Road, Cameron, WV 26033 or by email at sshala...@aol.com.