Burrowing owls face crisis from growth but have hope
A sudden burst of movement kicks up dust on what had seemed to be a vacant patch of dirt at Zanjero Park in central Gilbert. In the mid-morning sunlight, two bright yellow eyes stare forward, unblinking, framed by a brown and white feathered head that suddenly twitches in a cartoonish jolt, the eyes now appearing to be stacked on one another.
It’s easy to get lost in the quirks of this amusing little bird — a burrowing owl — but their plight is all too real. They are the only raptor in North America that lives underground, which puts them particularly at risk as development continues at a rapid pace across metro Phoenix, part of the fastest growing county in the country.
Zanjero Park sits across the street from a field where backhoes dig at construction sites, bordered by Loop 202 to the north and green agricultural fields to the east.
For years, the park has been a haven for burrowing owls which, despite their status as a federally protected species, are often displaced, their burrows destroyed by new development.
That puts the owls in a predicament: The grassland birds, which prefer sparse vegetation and plenty of open space to expand their territories, tend to live in agricultural areas where they can find water, insects, and rodents to eat and make burrows for them. That land is being rapidly developed as Arizona continues to urbanize.
“The largest footprint for how burrowing owls are affected in North America is here in Maricopa County,” said Greg Clark, the habitat coordinator for Wild At Heart, a nonprofit based in Cave Creek that is the global leader in burrowing owl rescue and relocation. The organization also rehabilitates and releases many other birds of prey.
“There’s more burrowing owls on agricultural land in the way of a bulldozer here than anyplace else. Right now, we are in a habitat emergency.” Greg Clark Wild At Heart habitat coordinator
“There’s more burrowing owls on agricultural land in the way of a bulldozer here than anyplace else,” Clark said. “Right now, we are in a habitat emergency.”
Since 2009, after the housing market collapsed, Clark relocated 60 to 70 owls a year. Last year, with another housing boom, his numbers shot up to 200, and since then he’s been scrambling to find new habitat for the birds.
He tries to maintain a buffer of two years, so that as the owls come in, he remains two years away from running out of habitat. All of that changed last year.
“All of my buffer habitat was wiped out in a single year,” Clark said. “That put me into the hole big time. Right now, I’m scrambling to find sites with the cooperation of private landowners and government landowners. I need to find places for them somewhere, anywhere.”
Finding owls a new place to live
On a recent Saturday morning, a white truck pulled into Zanjero Park, towing a white trailer. A large outline of a barn owl’s distinctive widow-peaked forehead and almond-shaped eyes peered out from the trailer, below the slogan “Building New Homes for Owls.”
Clark and a small team of volunteers were releasing nine burrowing owls into newly installed artificial burrows — 5gallon buckets buried at least 4 feet underground and connected to the surface by way of flexible plastic tubing. The buckets create large nesting areas for the owls that are deep enough in the ground to remain cool in summer heat.
The volunteers methodically worked together to take down two “tents”— square, netted enclosures that had housed the owls for the past 30 days so they could adjust to their new surroundings. They had all been rescued from construction sites across the Valley.
One owl flew back and forth in the tent, occasionally stopping to strut on the ground and analyze the humans digging up the dirt that held the netting down and kept it in the tent.
“Yeah, we’re getting there, buddy,” said David Carr, one of the volunteers. As the volunteers gingerly peeled off the netting, the little owl flew toward some nearby brush and landed, turning its head in another yellow-eyed stare at the humans.
“From day one he was ready to get out of there,” Carr laughed.
Carr had helped to feed the newly rescued owls over the past month. He’ll continue to bring mice over for the next week, by which time the owls should figure out the hunting situation in the park for themselves. First, they will pick from the assortment of available artificial burrows, and hopefully stay to find mates. Nesting season is just beginning and their population depends on healthy clutch sizes.
The burrowing owls’ predicament began with the decimation of prairie dogs, whose population has declined 95 percent in its range across the West. Starting in the 1800s, farmers and ranchers exterminated the native rodents, thinking they were a threat to crops and grazing land. Urban development has only added to their challenges of survival.
“The prairie dog is called the ‘architect of grassland,’” Clark said. “By eliminating the prairie dogs, it actually began the process of degrading the grassland. The other side effect is it eliminated the main creator of owl burrows.”
The burrowing owl relies on rodents like the prairie dog, which create intricate burrows deep in the ground. The owls take up residence in the prairie dog burrows, where they can keep the rodent population in check and raise their young safely.
With the drastic decline in natural burrows, the owls have had to resort to living in drain pipes and ditches, even electrical boxes and other makeshift “burrows.” As a result, their reproduction has slowed, mortality has increased and their populations continue to decline.
Still, burrowing owls are in a unique position to survive, and even thrive, in urban environments. Since 1993, Wild at Heart has built thousands of artificial burrows across Arizona and can claim a string of successes.
When Clark joined the organization, he used his background as an engineer to improve the artificial burrow technology and make it more specific for the Arizona climate. Clark and his volunteers have built about 7,000 burrows over the years, providing homes for even more owls.
The program is recognized as one of the most successful conservation and habitat restoration programs in the United States.
“We need to get our minds around the idea that diversity is good, that we need to give up a little something in terms of space, for the benefit of the owls,” Clark said. “We can’t really stabilize the population. All we can do is slow the decline.”
Rescuing the owls from risk
While Clark works on the relocation side of the process, Bob Fox, who cofounded Wild at Heart in the early 1990s with his wife, Sam, is on the rescue end.
“If the public sees signs of development, my phone starts to ring,” Fox said.
Usually, people will notify Fox if they see construction in an area where they’ve noticed owls. Sometimes, the developer will do an environmental survey on site, which triggers a permitting process that allows Fox to collect the owls and bring them to Wild at Heart’s headquarters in Cave Creek. The birds are kept in aviaries there for at least 60 days so they lose their attachment to their old territory and don’t fly directly back to the site they were rescued from.
In the middle of the night, when it’s quiet and the owls are in their burrows, Fox goes to the development site and sets traps. Once he’s lured the pairs out and safely captured them, he digs into the burrow himself to make sure he’s not leaving anyone behind. The process can take anywhere from two hours to three days.
He’s had to dig 14 feet under a roadway in Gilbert, where he wound up finding a nest with six eggs. He’s come noseto-nose with badgers and felt the heartclenching sensation of blindly grabbing hold of a Colorado River toad.
“This always happens at 1 o’clock, 2 o’clock in the morning, you’re down in a trench, sideways reaching in and you don’t even want to know what you’re touching,” Fox said, laughing. “Sometimes I have a camera I put down before I go in and it looks like a nightmare from Tim Burton — spider webs and bugs crawling all around, and I’m like, ‘Do I really want to put my hand in there?’”
He almost always does — except that one time when there was a rattlesnake sitting outside a burrow. He had to come back for that one.
For the most part, developers are willing to work with Wild at Heart, Fox said. The issue is awareness.
“Developers are really pretty much in line with the idea of doing this, because they don’t want to just go out and bury animals,” he said.
Students and real-world research
About six years ago, a pair of burrowing owls attempted to nest in a small irrigation ditch at Estrella Mountain Community College in Avondale. The ditch wasn’t exactly a safe spot to lay eggs, and the school was about to grade the ditch to make way for a new performing arts center.
Rachel Smith, a biologist and Estrella Mountain professor, noticed the owls. She had been volunteering with Wild at Heart for several years, so she called them. What resulted led to new research on burrowing owls, which are difficult to study because they live underground, and gave students real-world lab experience during their undergraduate careers.
Smith and Wild at Heart built artificial burrows adjacent to the performing arts center and bordering the parking lot. Years later, when the school added a solar field to the property, they relocated the owls again and built even more burrows around the solar field. Now, the campus has about 50 burrows occupied by owls.
“They’re the perfect research animal,” Smith said. “They don’t fly away, they’re not scared, they’re not hard to see, they look cute, they’re high profile so the campus loves having them, and everybody loves talking about them. It helps us raise our profile in science, it helps us with our students. It’s just a really positive thing to have on this campus.”
It was also an opportunity to do hands-on research. Smith asked Clark and Fox what would be useful to them; they said they needed help determining the sex of many of the owls.
“I was looking for more projects to do with my students, especially more labbased research,” Smith said.
Smith, with her students as her assistants, developed a new, soon-to-bepublished method of identifying the sexes of the owls. Burrowing owls are different from other raptors in that they are nearly impossible to tell male from female without DNA testing. Since Smith had a background in natural genetics and DNA, it was a perfect research opportunity.
Over about two years, Smith developed a method to extract DNA from the owls’ feathers. She’s determined the sex of more than 500 owls for Wild at Heart.
“It’s a great collaboration,” Smith said. “There are many studies that show that introducing real-world research to undergraduates in science, and even non-majors, is really powerful. So we have a situation where we can actually do real research that is not just made up to have a project. It’s really needed.”
Most of Smith’s students have gone on to four-year degrees or graduate studies, Smith said, a result she attributes partially to the hands-on experiences the students got with the owls.
“This is a really good opportunity for me,” said Brandilyn Castro, a sophomore at the college who is working with the owls. “I don’t know of any, especially community colleges, that do something like this. It really feels like a research team.”
A model for coexistence
Greg Clark imagines a world where burrowing owls and other species are a key part of an increasingly urban environment, not just a problem to be dealt with or relocated.
“One of my goals would be to turn the corner to where burrowing owls become part of the community rather than something that is temporary or could leave at any time because of development,” Clark said. “What if they’re viewed as an essential part of a park, or a greenbelt area, or a new warehouse that’s been built?”
It’s well established that burrowing owls, and birds of prey in general, are a valuable part of the ecosystem. Some, like vultures, are keystone species, essential to stopping the spread of infectious disease and keeping the environment clean. They keep rodent and insect populations down and are an indicator of the overall health of an ecosystem.
“The more that we focus on the benefits of burrowing owls, and that wildlife in general count towards a healthy community, the better,” Clark said. “Once the irrigated agricultural land is gone, the population of burrowing owls will be on the bottom unless we figure out new and innovative ways to add them to communities.”
Lake Havasu City was never a place burrowing owls historically lived, but once people moved in and pumped water to lawns and parks, the rodents came and the owls followed. They took up residence in manmade washes where ground squirrels and wood rats dug burrows.
“I started to see them around town and was surprised,” said Dr. Kerrie Anne Loyd, who in 2015 moved to Lake Havasu City from Georgia, where she had studied suburban ecology. She is now a lecturer and biologist with Arizona State University extension in Lake Havasu. “I was interested in how they were making a living here. What I found was these birds were living right next to residences in the dry rivers or the washes that run through our town.”
Loyd also noticed a lot of dead owls, so she sent them to Arizona Game and Fish for toxicology testing. Most of them had died from rodenticide poisoning.
She canvassed neighborhoods that had particularly high rates of dead birds. Meanwhile, the Environmental Protection Agency started to ban some of the more commonly used poisons after they were shown to also be harmful to human health.
As residents stopped using rodenticide, the birds rebounded and the rodent population stabilized. Although some burrowing owls like adorning the outside of their burrows with dog feces (researchers are studying why), Lake Havasu City residents have embraced them.
Burrowing owls are listed as endangered in Canada, threatened in Mexico and are a species of concern in the U.S. Still, Loyd said, you see them thriving in agricultural and some more urban areas. “People are really interested in them, a lot of people photograph them, keep an eye on them,” she said.
Burrowing owls, charismatic and nonthreatening as they are, are an easy species to learn to get along with. But can the adoration for the little daytime owls translate into more respect for other, perhaps less cute, species?
“We need more research on that,” Loyd said, as any good scientist would.