More than 30 bohemian waxwings were killed after colliding with a glass walkway at Ottawa City Hall, according to a local group devoted to reducing bird deaths.

Safe Wings Ottawa began tweeting photographic evidence Saturday of the discovery of dead and injured bohemian waxwings beneath the walkway, which connects the main city hall building with the nearby heritage wing.

Feeling the worst sense of deja vu as another flock of Bohemian Waxwings collided with City Hall tonight, like 2013. <a href="https://t.co/EfcrvGA5sM">https://t.co/EfcrvGA5sM</a> —@SafeWingsOtt

Current <a href="https://twitter.com/ottawacity">@ottawacity</a> Bohemian Waxwing tally: 32 dead, 5 rescued, 13 badly hurt in trees <a href="https://twitter.com/hashtag/ottcity?src=hash">#ottcity</a> <a href="https://twitter.com/hashtag/ottnews?src=hash">#ottnews</a> <a href="https://twitter.com/JimWatsonOttawa">@JimWatsonOttawa</a> —@SafeWingsOtt

Of aprox 60 birds only 20 flew off safely. Help us <a href="https://twitter.com/hashtag/preventcollisions?src=hash">#preventcollisions</a> and save lives! <a href="https://twitter.com/hashtag/ottcity?src=hash">#ottcity</a> <a href="https://twitter.com/hashtag/ottnews?src=hash">#ottnews</a> <a href="https://t.co/ZEx002Ll1y">pic.twitter.com/ZEx002Ll1y</a> —@SafeWingsOtt

Anouk Hoedeman, the program's coordinator, told CBC News that the waxwings — small, stocky, starling-sized birds — are drawn to the area because it's a plentiful food source.

"They're flying back and forth between the fruit trees and the other trees and they crash into the walkway because they don't see the glass. It's clear glass," said Hoedeman.

As of Sunday afternoon, there were 34 dead birds, said Hoedeman, while another five injured birds had been transported to the Wild Bird Care Centre.

There were also likely about "half a dozen to a dozen" injured birds that rescuers couldn't reach because they had escaped to nearby trees, she said.

Anouk Hoedeman of Safe Wings Ottawa. The group of volunteers wants the city to adopt a bird strategy, including guidelines for developing bird-friendly buildings, and beefing up rules about outdoor cats. (CBC)

Similar incident in 2013

On its website, Safe Wings Ottawa offers a number of suggestions for how the city can make itself safer for birds, including retrofitting municipal buildings with "effective collision deterrent solutions" and creating a local bird strategy similar to what exists in Vancouver.

It's not the first time birds have been killed the walkway: dozens of waxwings died in 2013 after a similar incident.

On Sunday a worker was installing temporary shielding along the walkway to prevent future collisions, but Hoedeman said she hoped more would be done.

"We've proposed maybe whitewashing [the walkway] or doing something else temporary but quick," she said. "Long term I'd like to see them install some kind of a proper treatment for the window to make it visible."

'Absolutely tragic'

Coun. David Chernushenko called the bird deaths "absolutely tragic" and said Sunday he planned to bring a formal inquiry to city council to find out what's being done at the municipal level to prevent further bird impacts.

He also hoped to adopt "potentially mandatory" guidelines for new buildings so they're not built in a way to be harmful to birds.

"It's painful for a lot of people to see this. And it's something that is avoidable," said Chernushenko.

"You may want a lot of glass in your building, but there is a tragic consequence to that. And we've just got to build differently and build smarter."

The City of Ottawa could not be reached for comment Sunday.