Did development drive them off?

Most people can count on one hand the owls they’ve seen in the wild. Iconic, comical, and widely loved, owls are a rare treat to observe because they hunt at night and generally steer clear of humans.

Except for the burrowing owl, that is. This small, sandy-colored raptor with bushy eyebrows and stalky legs ranges across North America, and by all accounts used to be a daily sight in the sand hills of Corrales.

“They’re wonderful little creatures,” says Mikal Deese, a wild bird rehabilitator who has lived just below Rio Rancho for about 20 years. “There used to be a nest at the top of the hill, and their heads would pop out. The parents go in and out to feed them, and eventually the babies come to the entrance—and they’re just precious, looking out, going, ‘Ooh, wow, the world!’

“When construction started, they disappeared.”

Burrowing owls nest in ground holes in desert, scrub, and grasslands, and are often active during the day. Since they are poor diggers, they tend to use any burrow they can find, though historically they have relied on the plentiful prairie dog. As prairie dogs have been wiped out across the West, burrowing owl numbers also have fallen.

“There used to be a lot of burrowers in the foothills,” says Shirley Kendall, another Corrales bird rehabilitator. “It used to be fun to sit in the sand and watch them—large families would compete for food. But they’ve migrated on.”

As Rio Rancho grew, and new homes marched down the hill and across the mesa, the once-common burrowing owl has all but disappeared from Corrales. It’s sad, as Kendall put it, “what humans do.”

Or is that really what happened?

The life and habits of the burrowing owl, it turns out, share some of the controversy of their spotted cousins to the north. Talk to owl watchers and avian biologists, and there’s not much agreement on why these curious creatures are declining across New Mexico—or even if they are.

“There are a lot of other variables” besides habitat loss, says Carol Finley, coordinator of the New Mexico Burrowing Owl Working Group, a partnership of public and private agencies formed specifically to document what’s happening with the burrowing owl. The species is protected by the Migratory Bird Treaty Act, which calls for heavily fining developers caught destroying animals or nests. Yet owl numbers have fallen steeply in some areas of the state.

At Kirtland Air Force Base, where Finley is natural resource manager, the resident burrowing owl population has plummeted from 57 breeding pairs in 1998 to 14 this year, according to a monitoring and banding project. Finley suspects badgers and coyotes are to blame. “Predators have an up and down cycle too,” she notes. Drought may also affect what is available for owls to eat: insects, reptiles, rodents, and small birds. “They produce less young if there’s not a lot of food around,” Finley adds.

Home development, of course, continues to disturb what was once open habitat. But construction is not always what drives owls from a particular site. After migrating south in winter, the owls usually return to the same place each spring, sometimes to the same burrow. And they can be quite persistent in the face of disturbance, according to Kristen Madden, a state biologist and clinic director of Wildlife Rescue Inc. Owls returned to a highway median in Los Lunas, for example, and had to be trapped and moved, she said.

Famously open-minded as squatters, burrowing owls have been found under sidewalk cracks, in drainage pipes, city parks, suburban lawns, and irrigation banks. “Some have tolerated high levels of disturbance around their burrows,” according to a 2001 report by the Raptor Research Foundation, which adds that construction accounts for only a small share of cases where owl numbers are declining.

At Kirtland, for example, as well as at New Mexico State University, the Raptor Research report found owl numbers falling with no overall loss of habitat. Banding projects at those sites have found that while owls generally return each year, some stay away, and unbanded ones always show up. Some owls disappear for years, then come back. No one knows why.

But Yvonne Boudreaux scoffs at this line of reasoning. As head of the Albuquerque rescue group Prairie Dog Pals, she notes that Kirtland protects owls and owl burrows while “poisoning prairie dogs elsewhere on the base.”

With a loss of 98 percent of prairie dog range across the West, Boudreaux says, owl decline is no mystery. Indeed, the Raptor Research report notes that the loss of prairie dog habitat is probably one of the most important factors in the owls’ decline, and that the two species have evolved together so long, “it is not yet clear how the owls will fare in their association with rock squirrels”—apparently their burrow partner of second choice.

Prairie dogs have not been abundant in Corrales, however, and the burrowing owls here likely used holes made by squirrels, rabbits, mice, and snakes. Corrales owl-watcher Susan Weiss thinks the population simply crashed, as so often happens in the wild. “Sometimes the crash takes two or three years to be complete,” she notes.

Biologist Jim Findley, who has watched specific burrows in Corrales for years, believes human activity scared them off. “It’s the traffic on the arroyos, which get used for more and more things, and get built right to the edges,” he says.

Clearly, much is not known about the owls after a decade or more of study. It’s unknown exactly where New Mexico’s owls go in winter, for example, or what they encounter there. The one thing everyone agrees on is the need for more information. The Burrowing Owl Working Group has a form on its website (www.nmburrowingowl.com) where people can report owl sightings.

Madden, for one, believes burrowing owls are still present in Corrales. But don’t go peering into any burrows—the owls make a sound just like a rattlesnake when threatened. Take your photo and file a report, because nothing happens in this world without data.

“It’s easy to point to something and say that’s why a species is failing,” Madden says of the conventional wisdom on Corrales owls. “But it’s rarely just one reason.”

Burrowing owls tend to their young at Kirtland Air Force Base. Owls are banded and followed at sites including Kirtland and New Mexico State University in an attempt to understand their habits.