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

Economic inequality, immigration still need work in Victoria: Prosperity index

Housing, environmental health factors show improvements in 2019: report

WATCH: Soon-to-be guide dogs take part in the Amazing Puppy Race

10 puppies training to be guide dogs took part in a social Easter egg hunt

Victoria City Councillor Laurel Collins wins federal NDP nomination

Collins will run for Victoria in the upcoming federal election

Long weekend starts with series of crashes

The long weekend traffic pile up is starting with a series of… Continue reading

Victoria church bells toll in solidarity with Notre Dame Cathedral after devastating fire

Churches around the globe ring bells to honour iconic Paris cathedral

POLL: How often does your family use BC Ferries?

Navigating the lineups for BC Ferries is a way of life for… Continue reading

Crime Stoppers most wanted for Greater Victoria for the week of April 16

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

B.C. senior sentenced for sexually abusing special-needs granddaughter

73-year-old Cortes Island man will go to jail for three years

Howe Sound Queen sailing toward retirement

Vessel now up for auction ends regular runs between Crofton and Vesuvius at the beginning of June

Should B.C. lower speed limits on side roads to 30 km/h?

Vancouver city councillor wants to decrease speed limits along neighbourhood side roads

Lawsuit eyed over union-only raise for B.C. community care workers

‘Low-wage redress’ leaves 17,000 employees out, employers say

Landlord of alleged Okanagan shooter recounts deadly day

Tony Friesen was working in one of the units of his Penticton building when he heard shots

Foreign national arrested in connection to thefts at YVR

A woman, 60, is being held in police custody as Richmond RCMP investigate

Most Read