Scientists estimate that up to 42 million birds are killed from collisions with glass in Canada every year. That estimate goes as high as nearly 1 billion in the U.S., according to Krista De Groot, landbird biologist with the Canadian Wildlife Service, who spoke at the Insulating Glass Manufacturers Alliance Summer Conference 2018 last week in Vancouver, British Columbia, Canada.
The seminar, “Bird Collisions with Glass: An Opportunity for Conservation and Innovation” explained the causes of bird collisions with glass and offered several solutions.
According to consultant David Bruce, birds consume more than 100,000 metric tons of insects daily, making them important to the world ecosystem. Birds also consume millions of agricultural pests, pollinate wildflowers and spread seeds.
De Groot said that glass has become a serious conservation threat to birds.
“They collide with glass wherever it’s found in the built environment, including patio rails, noise barriers, wind breaks, greenhouses and buildings,” she said.
“Even if you look at the lowest end of the estimates, that’s around 365 million bird deaths in the U.S. each year. That’s equivalent to 445 Deepwater Horizon oil spills every year,” said De Groot. “The issue gets swept away. Many maintenance workers are instructed to sweep dead birds away in the early morning. Scavengers eat the dead birds as well.”
She explained that when migrating birds reduce their altitude toward morning or during inclement weather they become exposed to city light and become vulnerable to structures in their air space. During the daytime when flying, birds’ lack of frontal vision makes them susceptible to clear glass collisions. They will attempt to fly through it to get to vegetation on the other side.
“If birds crash into clear glass going at high speeds it is fatal,” said De Groot.
She said that reflective glass is also a major issue, because it can be a perfect mirror of vegetation and sky. College campus are a major problem area because of the tendency for large windows to be in proximity to nature.
“Windows of any size can cause collisions,” she said. “The solution is to make the glass visible to birds with visual markers.”
Markers need to be on surface one of the glass for birds to see them clearly. High contrast markers allow birds to see them from far away. The gaps between markers shouldn’t be more than 4 inches or 10 cm horizontal, and 2 inches or 5 cm vertical because birds can fly through small spaces.
“For decals to be effective they have to cover the whole window,” said De Groot. “You can’t just stick one decal on a window and expect it to be effective.”
Several cities offer incentives for bird-friendly practices and a growing number of jurisdictions have bird-friendly building guidelines.
“LEED has Pilot Credit 55 which encourages the reduction in use of glass or use of glass with bird-friendly patterns,” said De Groot. “There are many retrofit and aftermarket products available.”
There are a number of bird-friendly glazing options available such as Arnold Glas’ Ornilux Mikado, which includes a UV pattern on surface three; Walker Glass’ AviProtek, which includes acid etching and UV on surface one; and GlasPro’s Bird Safe, which includes UV ink on surface one.
“There’s an opportunity for innovation here. Taking action to mitigate bird collisions with glass is gaining momentum,” said De Groot. “There is a growing market for bird-friendly glass.”