Thwunk. The sickening sound of a songbird colliding with a window. We’ve all heard it, and had our hearts go out to the stunned, injured or dead birds. Hundreds of millions of birds die in the U.S. each year from the invisible threat of glass, a cause of avian mortality second only to domestic cats in taking a tremendous toll on populations. The amount of glass on a building is the best predictor of the number of bird deaths it will cause. Window deaths affect reproductively active adults, and have an out-size impact on populations.
Most building bird deaths occur in daytime. Bird eyes are located on the sides of their head. They have little depth perception. They don’t perceive right angles or glass panel edges. Reflections of vegetation and sky can be particularly deadly.
Night lighting in urban areas disorients night-migrating birds, and they collide with glass. Bad weather causes birds to fly lower and closer to lights, but not all the biological factors are known. Designing or retrofitting buildings to reduce excessive or inefficient lighting can both reduce collisions and decrease light pollution. Some cities now have “Lights Out” programs, encouraging building owners and occupants to extinguish lights during spring and fall migration periods.
A recent Idaho Matters program highlighted how light pollution from Boise’s burgeoning growth now jeopardizes the central Idaho Dark Sky Reserve designation. This designation is important in promoting astral tourism. We are ruining this opportunity.
Boise has begun to take steps towards sustainability by adopting climate-conscious policies. Protecting biodiversity is a fundamental part of sustainability. An alarming new study has found that North America lost 3 billion birds since 1970, a 29% decline in populations. Concerned cities across the country are adopting new ordinances and programs to protect birds. New York City just adopted a landmark bird-friendly construction ordinance.
Boise has an opportunity to be a leader, and to make a real difference in conservation of avian species in the western U.S. Songbirds must “refuel” on insects during migration. The riparian Boise River corridor and the urban forests of the City of Trees are great resources for migrants. Beautiful yellow/black/red Western Tanagers, vivid Yellow Warblers and many other species descend on our city’s trees seeking insects. Making the city safer for birds is our conservation responsibility. Awareness is growing. BSU students recently documented the lethality of the new campus Arts building. Adopting design standards for new construction to help save birds is an important step towards urban sustainability. These efforts would involve careful coordination between several existing city Commissions.
The American Bird Conservancy has assembled information on ways new construction can incorporate bird-friendly design that is cost neutral. Older buildings can be retrofitted to reduce mortality, keeping costs down by targeting specific areas of buildings where most collisions take place. The city could provide expertise to assist property owners who wanted to retrofit buildings to reduce mortality.
Mayor-elect Lauren Mclean was recently quoted in this newspaper stating: “We need to create a new path to starting a conversation with our residents about a downtown library that is worthy of our city, appropriate for our time, and celebrated by our community”. Bird-friendly design must be a primary element of any civic project if it is to be appropriate for a city in a World facing a biodiversity crisis.
I urge the new Mayor and City Council to move forward on exploring urban design features and policies that save bird lives and advance the cause of bird conservation.