Fear itself enough to control mammal populations, study suggests

UVic study could offer hope for those who want to see the region’s deer population controlled without resorting to a cull.

A University of Victoria study could offer hope for those who want to see the region’s deer population controlled without resorting to a cull.

Predators lower the population of their prey, not just by killing them, but by scaring them as well.

It’s a conclusion made by a team of researchers who believe behavioural research collected on song sparrows in the Gulf Islands could be applied to predator-prey interactions of all kinds and used to manage their populations.

“The fear of falling victim to a predator can also have significant effects and affect the number of babies you have,” said Michael Clinchy, adjunct professor at the UVic and co-author of the study. “This can be as important as direct killing in reducing prey numbers.”

Over the past 10 summers, Clinchy, along with University of Western Ontario biologist Liana Zanette and UVic grad students, used electric fencing and fish-netting to fully protect sparrow nests from natural predators such as owls and raccoons on Portland Island and surrounding Gulf Islands. Through speakers hung in surrounding trees, one group of birds were subjected to recorded predator calls and sounds, while sounds of non-predatory animals such as geese played for a second group of song sparrows.

Clinchy and Zanette observed the birds via video and learned those exposed to predator sounds produced 40 per cent less offspring than the control group. These birds also spent more time guarding their nests and less time feeding their young, which also reduced their numbers.

“It’s the first time in any study of wild bird or mammal that fear alone has been shown to unambiguously affect birth and survival and thus the individuals in wildlife interactions,” Clinchy said. “Basically we think that this kind of fear effect is going to be pervasive on wildlife.”

Clinchy links his work to the management of elk populations in the American Yellowstone National Park and doesn’t overrule the possibility of controlling deer in Greater Victoria using the same principal. When wolves were reintroduced to the park in the mid-90s, the elk population decreased by 50 per cent – a reduction far greater than what the wolves were capable of killing, Clinchy said.

“It’s the fear itself that’s really responsible,” he said. “If you can simulate that, you could have effects in reducing the deer population.”

The study, Perceived Predation Risk Reduces the Number of Offspring Songbirds Produce per Year, was published in the December issue of Science magazine.

nnorth@saanichnews.com

Just Posted

‘The system has fallen apart:’ Victoria woman’s son died a day after being accepted to treatment centre

Victoria man’s body went undiscovered in Victoria parking lot for five days after overdose

Every situation is different, jurors hear at coroners inquest into Oak Bay teen’s overdose death

Pediatrician says involuntary treatment necessary following overdose, opioid use

CRD tickets cyclists who ignore stop signs at Lochside trail, Saanich Road intersection

Many cyclists don’t heed the stop signs, use pedestrian-activated crosswalk light

Inaugural Sarah Beckett memorial Run raises $20,000 for law enforcement scholarship

Widow calls run, community playground fitting tributes to fallen mom and Mountie

VIDEO: Victoria airport guests see dinosaur surprise

Two boys dressed as raptors get a shock when their grandmother comes to greet them

POLL: Do you think the penalty should be increased for tossing a burning cigarette from a vehicle?

With grasslands and forests around Vancouver Island and across B.C. reaching tinder… Continue reading

Greater Victoria wanted list for the week of June 25

Greater Victoria Crime Stoppers is seeking the public’s help in locating the… Continue reading

B.C. Ferries vessel breaks down right before long weekend

Horseshoe Bay-Langdale route impacted most, revised schedule adds 4 a.m. sailings

Weather Canada issues thunderstorm alert for coastal Vancouver Island

Severe thunderstorm watch issued around 4:15 p.m. as storms developed over sections of the Island

Nanaimo man gets jail time for posting explicit photos of ex-girlfriends

Man’s name cannot be revealed to protect victims’ identities

North Island thrift store robbed at knifepoint, say RCMP

Suspect fled on bicycle following Tuesday stick-up

RCMP across Canada to soon unionize, according to B.C. mayor

A spokeswoman for RCMP headquarters in Ottawa says it’s not yet a done deal

Most Read