By October of next year, bird-friendly glazing might be a requirement on certain buildings in Washington, D.C.

Five D.C. council members introduced the Migratory Local Wildlife Protection Act of 2022 to the D.C. Council on March 14, 2022. Mayor Muriel Bowser signed the bill on Jan. 26, 2023. It now goes to the U.S. House of Representatives and the U.S. Senate for 30 days before becoming law.

By October of next year, bird-friendly glazing might be a requirement on certain buildings in Washington, D.C. Photo courtesy of Maria Oswalt.

“We know that bird-friendly glass used in construction could prevent the needless death and injury of millions, if not billions, of birds,” Rep. Mary Cheh (D) wrote in the legislation’s introduction. “The District can do its part by prohibiting unsafe building materials that put birds and other migratory wildlife at greatest risk.”

If the bill becomes law, new construction building permits or alterations involving the replacement of all exterior glazing on commercial buildings, multi-unit residential buildings, institutional facilities, or District-owned and operated buildings will need to include bird-friendly materials up to 100 feet. This does not include historic landmarks and single-family homes.

Buildings would also need bird-friendly materials on all glazed corners and fly-through conditions above 100 feet. Additionally, the exterior wall envelope and any other fenestration installed adjacent to a green roof system or roof terrace will need to include bird-friendly materials up to 24 feet above the roof system and terrace.

The bill also ensures that all bird-hazard structures be constructed with bird-friendly materials throughout the building, regardless of height. The legislation defines a bird-hazard structure as monolithic glazing installations that provide a clear line of sight or mirrored surface on the exterior of buildings. This includes awnings, handrails and guards, windbreak panels, bus shelter enclosures, skywalk enclosures and acoustic barriers made of glass or glass-like materials.

Birds have a fraught history with glass. Because glass is clear, many birds believe they can fly through it. Reflectivity also causes glass to serve as a mirror, which tricks birds into thinking they’re flying through trees or clouds.

“Most birds that collide with buildings in D.C. are migratory birds, flying north or south along the Atlantic Flyway, the major pathway for birds along the east coast of the Americas,” Anne Lewis, president of City Wildlife, told NPR.

She adds that the most common birds killed in collision in D.C. are white-throated sparrows, ovenbirds, common yellowthroats and woodcocks.