Dick Clegg prepares to band one of three young owls in a barn in Chilliwack. See this owlet

Dick Clegg prepares to band one of three young owls in a barn in Chilliwack. See this owlet

What’s killing the barn owls of the Fraser Valley?

Fraser Valley is home to most of Canada's barn owls, but the harmless birds' survival is threatened by factors such as rat poison.



Retired Chilliwack farmer Allan Peters had no idea that the rat poison he used around his former dairy farm may be harming local barn owls. But since local veterinarian Dick Clegg installed a nesting box in Peters’ old barn, Peters has grown protective of the charismatic, gold-coloured birds with a pale heart-shaped face that swoop at the rafters of his building.

The neighbouring organic vegetable farm has also seen its rodent problem vanish since barn owls started nesting in Peters’s old barn, according to Clegg.

Clegg has been working to protect barn owls in the area for over a decade. The Lower Fraser Valley is home to an estimated 250 to 1,000 adult barn owls, representing most of Canada’s population.

Recently, the species was upgraded from being of “special concern,” to “threatened,” reflecting a decline in numbers.

When frightened, barn owls screech and sway in unison, successfully intimating any predator or human that cares to look into their nesting box (see owlets hissing in video below). But these tactics can’t protect against the most common reasons for the species’ decline.

One is habitat loss. Barn owls love old cottonwood trees, but have grown fond of decrepit wooden barns as well. As these are torn down and replaced with modern glass-and-concrete structures, owls have fewer places to rear their young.

Another reason may be the proliferation of second-generation rodenticides, which Clegg believes to be the biggest killer of barn owls.

When rats eat poison from a bait box, they have about a week before they die, a deliberate lag to prevent them from figuring out that the boxes contain lethal material. But it’s during that time that rats are likely to be eaten by owls.

“The poisons now, what they call second generation, are much more potent. And they’re very insidious in that they stay in the environment a long time,” said Clegg.

Even animals that don’t eat rats, such as deer, have tested positive for rat poison.

“I find whole batches of owls in boxes like this, dead,” said Clegg, indicating the wooden nesting box high up in Peters’ barn. “Quite a few people around here know I’m interested in these things, and they’ll give me a call, and say, ‘I’ve got an owl in my yard. It’s walking around looking kind of weak. And, oh, it just fell over.”

Clegg picks up the dead owls and ships many to a research facility at Simon Fraser University. He has about ten in an office freezer right now waiting for shipping.

Researchers are still trying to figure out whether rat poisons directly kill owls. What they know, however, is that 75 per cent of dead owls tested by Environment Canada between 2005 and 2011 returned positive for rat poison in their livers. This is higher than the last testing period, 1988 to 2003, when only 66 per cent of owls came back positive.

Wildlife biologist Sofi Hindmarch, one of a handful of people studying barn owls in British Columbia, says that rat poisons may also have sub-lethal impacts on owls, such as affecting an owl’s ability to hunt or limiting its coordination, and thereby increasing the bird’s risk of being hit by a car.

The few adult owls and three babies currently nesting in Peters’ old barn haven’t caused the retired farmer any problems. Instead, they’ve been eating nuisance critters such as rats and starlings on nearby farms, adding to the raptor’s basic diet of meadow voles and mice. With the notable exception of enjoying blueberry stalks, the owls are harmless to most farming operations.

Clegg has installed about 120 nesting boxes over the last dozen years, and has heard multiple stories from local farmers that the owls have brought a rampant rodent problem under control.

“Just about anybody that’s got a box with owls in it, they’re very protective of them,” said Clegg.

Health Canada recently tightened its regulations on rat poisons, especially the most harmful, second generation ones such as brodifacoum and difethialone. As of Jan. 1 of this year, all rat poison products must be placed in tamper-resistant bait stations, rather than sold as loose bait. Rodenticides in meal, treated whole grain, pelleted and liquid forms have been discontinued by manufacturers since Dec. 31, 2012. Residents can still use their existing supplies until Dec. 31, 2016.

Clegg has recovered about 40 of the over 1,000 raptors that he has banded over the past decade, an effort he takes on voluntarily in order for researchers to gain a better understanding of the species. Most barn owls died young within a couple of years of birth, Clegg found, from being hit by a car. But whether that is related to ingestion of rat poison is anyone’s guess.

akonevski@theprogress.com
twitter.com/alinakonevski

Just Posted

Dancers from the Sts’ailes First Nation perform the eagle dance at a welcome banner dedication ceremony on Thursday, June 10. “Ey Swayel” is a Halq̓eméylem term translated as ‘a good day.’ (Adam Louis/Observer)
VIDEO: ‘A good day’ for Agassiz school as Sts’ailes welcome banner is dedicated

Banner hangs above the school’s entrance, welcoming students, staff and visitors

UFV athletes were honoured for their strength and perseverance during the pandemic. (UFV photo)
Fraser Valley athletes recognized in year without sports

UFV Cascades athletes honoured for strength shown during the pandemic

Missing Abbotsford man Adam Hobbs was found deceased on Thursday evening (June 17).
Body of missing Abbotsford man Adam Hobbs found

Hobbs was reported missing Monday after leaving his job site in Langley

A tenant walks in front of her home on Boundary Road on Friday, June 18, 2021 after it was destroyed by fire the night before in Chilliwack. (Jenna Hauck/ Chilliwack Progress)
Chilliwack family homeless after fire rips through house on Abbotsford border

Turtle rescued, no one seriously hurt following Boundary Road fire in Chilliwack

A small pod of Pacific white-sided dolphins pass by close to shore in Campbell River June 16, 2021. Still capture from video courtesy of Kimberly Hart
VIDEO: Dolphin sunset captured from Vancouver Island shore

Spectacular setting for view of travelling pod of Pacific white-sided dolphins

Police are asking for public assistance in locating Anthony Graham who has been charged with the murders of Kamloops brothers Carlo and Erick Fryer. (RCMP photo)
2 charged, suspect at large in killings of B.C. brothers linked to gang activity: RCMP

Kamloops brothers Erick and Carlo Fryer were found deceased in May on a remote Okanagan road

Albert Health Minister Tyler Shandro and Alberta Premier Jason Kenney unveil an opening sign after speaking about the Open for Summer Plan and next steps in the COVID-19 vaccine rollout, in Edmonton, Friday, June 18, 2021. THE CANADIAN PRESS/Jason Franson
Alberta 1st province in Canada to lift all COVID-19 public health restrictions

70.2% of eligible citizens 12 and older in the province have received a dose of the vaccine

Fraser Health registered nurse Ramn Manan draws a dose of the Pfizer COVID-19 vaccine into a syringe at a walk-up vaccination clinic at Bear Creek Park, in Surrey, B.C., on Monday, May 17, 2021. THE CANADIAN PRESS/Darryl Dyck
‘Honour our fathers’ with COVID-19 vaccine protection, B.C. urges

109 new cases Friday, 75 per cent of 12 and up immunized

(Paul Henderson/ Chilliwack Progress)
Trutch Avenue in Chilliwack to be renamed to remove racist taint

New name to have Indigenous significance as Chilliwack takes new step toward reconciliation

Join Black Press Media and Do Some Good
Join Black Press Media and Do Some Good

Pay it Forward program supports local businesses in their community giving

Cannabis bought in British Columbia (Ashley Wadhwani/Black Press Media)
Is it time to start thinking about greener ways to package cannabis?

Packaging suppliers are still figuring eco-friendly and affordable packaging options that fit the mandates of Cannabis Regulations

Canadian Prime Minister Justin Trudeau is seen during a joint news conference following the EU-Canada Summit, in Brussels, Belgium, Tuesday June 15, 2021. Trudeau says Canada is on track now to have 68 million doses delivered by the end of July, which is more than enough to fully vaccinate all 33.2 million Canadians over the age of 12. THE CANADIAN PRESS/Adrian Wyld
Vaccine deliveries enough to fully vaccinate all eligible Canadians by end of July

Three in four eligible Canadians now have their first dose, nearly one in five fully vaccinated.

A search is underway for a 75-year-old fisherman who went missing near Port Angeles Thursday evening. (Courtesy of U.S. Coast Guard)
Search continues for angler missing between Port Angeles and Victoria

Canadian, U.S. Coast Guard searching for 75-year-old man reported missing Thursday evening

Most Read