Three chicks were found by a worker in a nest in one of the recently dismantled sections of the old bridge, which spanned the Fraser River between Surrey and Coquitlam.
"Unfortunately, the section was moved before they were spotted and they could not be reunited with their parents," said a statement on the Facebook page of Burnaby's Wildlife Rescue Association, where the owls were first taken.
"It was a day before they arrived at Wildlife Rescue and they were cold, dehydrated, hungry and listless," the association said.
But after some fluids, some warmth, a little rest and some hand-feeding, "the siblings soon perked up."
The owls were transferred the next day to the O.W.L. Orphaned Wildlife Rehabilitation Society in Delta, which is better equipped to care for raptors.
Mindy Dick, one of the bird care staff members at O.W.L., told CBC Radio's The Early Edition that the youngest of the three has since died from an incident with one of its siblings, which can happen in the wild.
The other two owls are healthy and thriving, she said.
They are now with their foster mother, Cessna, one of the organization's permanent resident barn owls. Cessna was hit by a plane a few years ago and has a partially-amputated wing, and has since become a successful mentor.
"She is keeping them wild and defensive," said Dick of the grown barn owl. "They are in a wild setting here. We are just supplying food."
Goal will be to release to the wild
Once the baby owls grow bigger they will be moved to an outside enclosure where they will learn to hunt. The goal is to come to a point where the surviving owls can go back into the wild.
Dick said the two barn owls could end up being released this spring at a farm in the Fraser Valley through O.W.L.'s barn owl box program.
The program sets up boxes for owls to use for nesting on farms that agree to stop using rodenticide, or rat poison.
Dick said her organization treats too many owls and other birds of prey who have been poisoned after consuming rodents that have themselves been poisoned, and they want to encourage farmers to stop using the chemicals.
"A barn owl is going to work much better at pest control than rodenticide," she said.
Barn owls are designated by the Canadian government a species at risk, and while the use of rat poison is a problem for them, so is habitat destruction.
That's why these barn owls were likely found under a noisy bridge, said Dick.
"It's not totally uncommon that they nest under a bridge. It has happened before with bridges in the Lower Mainland," she said.
"It's because their habitat is being obliterated."