Striking buildings are one of the leading causes of bird mortality in the United States, killing nearly a billion birds each year.

But recent changes to Portland’s deadliest building for birds show that injuries and deaths can be prevented.

Maine Audubon volunteers have routinely found large numbers of dead birds around the MEMIC building on Commercial Street during annual surveys, according to outreach manager Nick Lund.

In some years, more than 30 killed or injured birds have been found near the six-story building, Lund said.

But exterior stickers installed on three floors of windows reversed that trend and saved lives.

“During our fall surveys, we found no dead birds there, which is a complete validation of the time and effort it took MEMIC to put them together, and real proof concept for bird-safe window technologies,” Lund said.

Birds can’t tell the difference between the real world and a reflection, so they fly at full speed towards the windows. The simple decals break up the veneer and let them know it’s not the sky or a habitat, Lund says.

MEMIC’s window covering looks like polka dot spots covering part of its exterior.

“Seeing MEMIC go from the worst building on the road to a perfectly safe building has been truly remarkable,” Lund said.

In a statement, Lily Hanstein, senior vice president of strategy and communications, said the company learned the building was high on the list of violators for bird strikes in 2021.

The decision to put stickers on the building was a challenge, but ultimately the right choice, Hanstein said.