Building Design That Protects Birds

Perhaps a billion birds a year die from flying into buildings, the Audubon Society estimates. Especially when migrating, our feathered friends see the sky or benign-looking landscapes reflecting from glass façades, and then, before they realize there’s danger ahead, thump, they’re gone. Not incidentally, the East Coast is a heavily trafficked migratory path for many bird species, so the advisory put out by the Minnesota Audubon chapter is of equal interest to Mid-Atlantic architects.

The overall rate of collisions at a given building is based on many variables, according to the Minnesota Audubon Society’s Bird-Safe Building Guidelines. Naturally, they suggest that solutions be implemented at the initial design stage, although modifications and operational changes are possible. Here are eight fundamental concepts they provide for a comprehensive bird-friendly design (keyed to the drawing):

Fundamental elements of a comprehensive bird-safe design strategy

A. Apply treatment to glass surfaces to make them visible to birds (whose vision extends well into the ultraviolet range)
B. Minimize confusing nocturnal light halos around office buildings by supplying task lighting options for after-hours work
C. Likewise, provide the ability to draw blinds or otherwise control light spillover after dark
D. Include a means to ensure that interior lights are off after work hours
E. Provide awnings or other means to block sky or landscape reflections on lobby windows from above
F. Angle glass 20 to 40 degrees out from bottom to top to reduce a bird’s strike angle and project reflections downward so an oncoming bird sees the ground in the glass rather than the sky
G. On exterior perimeter surfaces, avoid ventilation grates that can trap stunned birds after they fall
H. Use exterior lighting that projects downward and minimizes light pollution.

Can one design beautiful buildings that are bird-savvy? Just ask Jeanne Gang, FAIA,  the most recent architect to receive the MacArthur Genius Award. Her Aqua Tower, an 82-story landmark recently added to the Chicago skyline, is renowned for its variably projecting balconies and interestingly fritted glass surfaces. The undulating “inhabited façade” is both captivating visually and bird-protecting. Gang and her team not only aspired to create the natural look of eroded cliffs with the wavering terraces, they also specified glass fritted with a gray dot pattern and picketed railings on the balconies to enhance bird safety. Gang has long been an advocate of bird-safe design and has incorporated bird-safe strategies in a number of her projects.

Read the Minnesota Audubon report.