Owls can't digest the fur and bones of the animals they eat, so they cough up small pellets which prove handy for wildlife researchers. ((Ray Poulin))

Scientists in Saskatchewan say a project examining owl vomit is yielding tremendous information about Prairie wildlife.

The researchers, based at the Royal Saskatchewan Museum in Regina, put out a call in 2008 asking people to send them samples of owl vomit. The scientists wanted to study the regurgitated material to see what small animals were being consumed by the birds.

"Owls cannot digest the fur and bones of the mammals that they eat," explained Ray Poulin, a biologist at the museum. "So, to get rid of them, they cough them up in a convenient pellet form."

To study the pellets, the researchers remove the hairy bits in the laboratory.

"We bring them back to the lab here, and we effectively digest away the fur parts ... and we're left with bright, white clean bones that we can use to identify what the owls have been eating," Poulin said.

Poulin, who is the museum's curator of life sciences, and his colleagues decided to use the vomit of owls for their research because the birds are far more efficient at gathering samples than humans.

In effect, hungry owls do most of the scientists' field work.

Combined with their own efforts, Poulin said researchers gathered 3,400 pellets for study. The samples came from more than 500 different spots across Saskatchewan, primarily south of Nipawin and Prince Albert.

"We've got a lot of work ahead of us," Poulin said, referring to the analysis part of the research now underway. "We've identified about 10 per cent of the contents of the pellets, which has translated into over 5,000 mammals so far from 25 different species, which is just incredible."

Owls much better than mousetraps

At the rate things are going, Poulin estimates he and his colleagues might end up identifying 50,000 small mammals through the pellets.

"If we were using mousetraps ... it would take me about one million trap nights to catch that many small mammals in the Prairies."

The results so far have turned up remnants of rabbits, weasels, bats and the more common shrews, mice and voles.


Owls, such as this young Great Horned Owl, are efficient 'mousetraps' for field scientists. ((Ray Poulin))

The owls also coughed up fish bones, snake teeth and countless insects and invertebrates.

"These owls are really good at what they do," Poulin said. "This is why we selected them as 'the best mousetrap.'"

Some animals, such as the sagebrush vole, are especially tricky to trap by humans so determining their numbers is very difficult.

Previously, officials, at a loss to say if the species was endangered or thriving, simply marked it as "data insufficient."

However, the research gleaned from the owl pellets has generated more useful information.

"We're finding that it's the second or third most common species of small mammals that the owls are catching," Poulin said. "So, here we can't catch them at all ... but the owls are having an easy time of it."

More research on the findings would be needed to rate the vole.

Poulin said he was not surprised by anything in the vomit, including the presence of fish bones.

He attributed those finds to the great-horned owl, which Poulin described as "the great white shark of the bird world."

"I think, if they could, they would eat licence plates," Poulin added. "They will eat just about anything that moves." 

Poulin said the research will be valuable for years to come.

"Saskatchewan, in particular, is not well studied for its small animals," Poulin said. "We've got species that are probably here in the province that we've never found."

Finding them is important for developing management plans and for the pure science of studying the animals.

Poulin said researchers are still interested in receiving pellet samples but plan to be more selective, focusing on certain regions.

He said they would like to get information about areas around the South Saskatchewan River near Leader and the eastern side of the province.