Wildlife biologists are tricking these burrowing owls to help them move homes

In San Diego, Calif., as developers bulldoze open grasslands to make way for new houses and roads, conservationists say they have been destroying the homes of western burrowing owls.

Burrowing owls live in humble holes in the ground, eat live mice, and thrive on community. Recognizing those needs, wildlife officials have now used that spirit of togetherness and partnered with the developers to figure out how to move the owls to a new habitat.

"We kind of tricked the owls into thinking that there were already other owls on the site," Colleen Wisinski, a conservation biologist at the San Diego Zoo Wildlife Alliance, told As It Happens host Carol Off. "[It] really encouraged them to stay and kind of sent them the message that they were in a good place."

We're probably pretty close to having a self-sustaining population- Colleen Wisinski, conservation biologist at the San Diego Zoo Wildlife Alliance

That trickery included painting fake owl droppings outside their new burrows and playing recordings of owls hooting — a technique that has surpassed other researchers' efforts to relocate the birds to new sites, she said.

"[We] tried to get in the heads of the owls and squirt the paint on the rocks like we were a little owl standing there," Wisinski said.

She and her colleagues published their findings in the Animal Conservation journal last week.

Making the move

With the U.S. Fish and Wildlife Service, the San Diego Zoo researchers first captured the owls by setting up special one-way doors on the burrows that were set to be bulldozed. When 44 burrowing owls left their homes that day, there was no way for them to get back inside.

The researchers then captured and moved the owls about 17 km away to a new habitat with ready-made burrows, decorated with fake droppings.

With burrowing owls, though, it takes more than real estate to call a hole its home. These owls seek signs of other owls and a sense of community, which is why Canadian conservation biologist David Bird says the added trickery takes the move to a whole new level.

"This is, in my books, a prime example of highly creative thinking to help out a threatened species," he wrote in an email to As It Happens. "But if they want to take it to an even higher level, spreading bits of cow manure just outside the burrow entrances would enhance their attractiveness even more."

According to Bird, burrowing owls commonly spread manure around their homes, perhaps to lure in their favourite food — dung beetles — or to mask their own smells from predators.

Thriving in their new homes

Once the California owls entered their new homes, the researchers placed so-called acclimation enclosures on top, which are simple structures made with wood frames and chicken wire. For 30 days, these enclosures were kept there to help the owls cope with the move and ensure that, once the enclosures were removed, the birds consider the new habitat their home.

"We've tried to really take the soft release idea, that they are in an aviary for a period of time to get used to their new location," Wisinski said. "I think in some [other] cases, owls were removed without being acclimated to an area, so they may have just been dropped off and had to fend for themselves."

These pre-dug homes work as well as they do, said Wisinski, because western burrowing owls don't actually do their own burrowing.They rely on other animals in the open, grassland habitat, such as squirrels, prairie dogs, and badgers to dig for them — and to watch for predators.

Currently, the western burrowing owl is being considered for classification as endangered in California. The species is listed as endangered in Canada and threatened in Mexico. 

Near the end of the acclimatization period, the researchers played the sounds of different burrowing owls making territorial calls. The prerecorded hooting went on for one week before and one week after the aviaries were removed.

Wise reactions

The researchers monitored the owls throughout this time using a remote camera and an audio recorder setup on the speakers that played those hooting sounds.

"We had owls certainly visit the whole setup and start trying to call back to that recording," Wisinski said. "And show that this [owl], ... he was a tough guy and this was his territory. So it was actually pretty funny and it showed us that it was working."

Over the last three years of the study, she said it's been encouraging to see the relocated owls which now thrive at two different release sites.

"We have been trying to establish populations in protected areas," Wisinski said. "We try to aim for having at least half of the owls stick around on the site and then having half of those birds successfully breed.

"We think we're probably pretty close to having a self-sustaining population there."

Written by Mehek Mazhar. Interview with Colleen Wisinski produced by Ben Basran.