A common yellowthroat warbler sits on the ground, unable to fly, presumably after hitting the glass building behind it Tuesday. Maine Audubon counted the bird in its new study on bird strikes on building glass in the Old Port. Brianna Soukup/Staff Photographer

Nick Lund and Jamie Bailey-Rittall walked from Portland Harbor toward the window-covered WEX building just after dawn Tuesday, likely appearing to early commuters as two people out for a morning stroll.

But Lund and Bailey-Rittall are part of a team on the lookout for birds that have died after hitting windows on buildings. The research, being conducted during the fall migration, is a first for Portland.

For the past 16 days, Maine Audubon staff, volunteers and a professor and students from the University of Southern Maine have found 13 dead or impaired migrating birds directly beside buildings. The survey will continue every day until mid-October, the end of the migration season.

As many as 365 million to 988 million birds are killed annually in the United States when they inadvertently fly into building glass, according to the U.S. Fish and Wildlife Service. As a result, more cities in North America have passed ordinances over the past decade requiring bird-safety measures on glass buildings, such as bird-safe glass on new construction. Bird-safe glass is constructed in a way that birds can see it is there, but it looks like normal glass to people.

Nick Lund takes a closer look at a common yellowthroat found on the sidewalk beside a glass building early Tuesday morning. Brianna Soukup/Staff Photographer

Lund hopes Portland will be the next.

“Look around, every new building today is glass,” said Lund, Maine Audubon’s outreach manager, as he stood in the middle of the Old Port on Tuesday morning.


Since Sept. 7, Maine Audubon staff and volunteers, in partnership with USM biology Professor Chris Maher and USM students, have walked a two-mile loop through the Old Port between Commercial and Congress streets in search of injured or dead birds. Maine Audubon also is working with Avian Haven, a bird rehabilitation center in Freedom; and the Portland Society for Architecture on the study.

Documenting how many birds are crippled or found dead beside buildings in the Old Port is a first step toward raising awareness – and perhaps influencing architects and city planners, said Maher.

“To see a pattern, you have to look over a long enough period of time,” said Maher, who designed the study. “But, already the data is suggesting that it’s potentially an issue. Hopefully, we will at least make people aware of it. People think glass buildings are beautiful, but there are consequences.”

A newer, mostly glass building on Fore Street stands next to a more traditional brick building with smaller windows. The Maine Audubon study is looking for dead birds beside both kinds of buildings. Brianna Soukup/Staff Photographer

While birds see and avoid solid structures, such as brick walls or even flecked glass, they can’t see glass that is transparent or reflects the sky.

The first-time survey in Portland is taking place during the fall migration, when millions of birds are heading to South America for the winter. It will be repeated in the spring, when the birds return.

Small migrating songbirds usually travel at night because winds are generally calmer, there are fewer predators out hunting, and the birds use the stars for navigation. So looking for birds killed by building glass at first light offers the best chance to find them.


So far the Portland survey has found three common yellowthroats, a Lincoln sparrow, a scarlet tanager and a northern flicker, among other songbirds. Three birds have been found beside the WEX building and two were discovered next to the Time and Temperature Building. Other birds were found beside eight other buildings in the Old Port.

Some birds have been found alive, but Lund said research shows birds injured by glass strikes do not survive because of significant internal injuries and trauma to the head.

In the past decade, changing architectural practices and new building ordinances across North America have tried to address the problem.

A seagull flies near the new Wex building in Portland on Tuesday. Maine Audubon organized walks throughout the bird migration months to try to get an idea of how many birds become victims of buildings designed with a lot of glass. Seagulls often prey on birds that have fallen to the ground after hitting glass. Brianna Soukup/Staff Photographer

In December, New York City passed an ordinance requiring bird-safe building designs on new construction to minimize avian fatalities. But in a city where up to 230,000 birds are killed annually, according to New York City Audubon, the ordinance followed years of efforts to make the Big Apple safer for birds.

In 2011, San Francisco became the first major U.S. city to require bird-safe buildings – half a dozen other California cities later passed mandatory bird-safe building ordinances, according to the American Bird Conservancy.

In Maine, the University of New England changed the original plan for the student center at its Biddeford campus and switched in 2017 to bird-safe glass because the university – which offers environmental degrees – sits on a migratory flyway at the mouth of the Saco River.


So far, no Maine community has passed an ordinance requiring bird-safe glass.

Christine Sheppard, the American Bird Conservancy’s bird collisions campaign director, said the Portland survey is a good first step toward changing building practices in Maine by building interest in bird-safe buildings.

“Legislation is great, but it doesn’t have to be a big glass building – 50 percent of collisions happen on people’s homes because people have a couple of bad windows,” Sheppard said. “As more legislation is adopted and more buildings are built, people will see that you can still have a glass building – and it also can be bird safe.”

From left, Nick Lund with Maine Audubon, Jaime Bailey-Rittall, a biology student at USM, and Cath O’Connor, look for a common yellowthroat warbler that Lund had put into some bushes at the beginning of their survey Tuesday. Seagulls could be eating many of the songbirds that get killed in building strikes. Brianna Soukup/Staff Photographer

On Tuesday, after the Maine Audubon dead-bird search came up empty after a loop around the WEX building, the small group circled the building again and found a maimed common yellowthroat on the sidewalk. The group stopped to observe the injured bird – and soon were joined by a gull that walked up behind them and proceeded to pace back and forth, likely waiting for the chance to devour the bird, Lund said.

And therein lies a challenge in the new study – Portland’s healthy gull population could be eating many of the migrating songbirds that get killed in building strikes.

“If we had waited just five more minutes, the yellowthroat would not have been there. So the dead birds we’ve found so far doesn’t tell how many have died by bird strike. It is the minimum,” Lund said.

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