When Worlds Collide: Developing Bird-Friendly Cities

By: Amy Walsh

On October 5th, more than 1,000 birds collided with McCormick Place in Chicago, Illinois. While Chicago has historically been one of the most dangerous cities for migratory birds, this catastrophe is the worst in recent history. Dave Williard, a staff member at the Field Museum, and his colleagues collected approximately 964 dead birds, as well as a handful of live ones. Another organization, Chicago Bird Collision Monitors, collected 450 dead birds and 300 injured birds. Events like this contribute to an estimated loss of up to one billion birds each year from building collisions alone.

There are over 1,000 different species of birds that migrate through the United States. The Migratory Bird Treaty Act (MBTA) of 1918 is the legal framework used to conserve and protect these species. A combination of four international treaties with Canada, Mexico, Japan, and Russia, the MBTA prohibits the take, including killing, capturing, selling, trading, and transporting, of migratory birds without prior authorization. When take of this magnitude occurs, people wonder whether there is justice under the MBTA. Yet, it was determined, under the M-37050 Memorandum of 2017, that the MBTA does not prohibit the “incidental” take of birds. Incidental take is take that results from an activity but is not the purpose of that activity. This memorandum alleviated any responsibility for the “accidental” death of migratory birds. Fortunately, in 2021, the U.S. Fish and Wildlife Service published a final rule that reverses that interpretation, and implements the MBTA as prohibiting incidental take. Nonetheless, it is still unclear whether building owners can be held responsible for these occurrences.

Many cities are encouraging architects to make buildings more collision-proof. Just two years ago, Illinois passed the Bird Safe Buildings Act, requiring bird-friendly design to be incorporated into construction. However, it only applies to new and renovated buildings owned by the state. Other cities, such as San Francisco, have been implementing bird-friendly construction practices for years. Typical modifications include reducing reflective surfaces by creating patterns with decals or installing external screens and moving objects away from windows.

Another significant contributor to building collisions is light pollution. When birds migrate over large cities, the bright artificial lights can be disorienting, causing collisions with heavily lit buildings. Even when birds don’t collide with buildings, the lights can cause the birds to reroute, resulting in exhaustion and exposing the birds to other threats. To minimize the dangers of light pollution, the National Audubon Society, a nonprofit dedicated to the conversation of birds and their habitats, has developed the Lights Out program, working with building owners and managers to turn off excess lighting during heavy migration periods. Some examples of efforts include turning off or down-shielding exterior lighting and installing automatic motion sensors. A 2021 study done by McCormick Place, where the recent incident occurred, determined that shutting off half of the lights in large buildings can reduce collisions by six to eleven times. While some cities participate in this program voluntarily, more consistency will ensure the avoidance of these mass collision incidents.

There are additional opportunities available to support cities in their efforts to conserve birds. The U.S. Fish and Wildlife Service established the Urban Bird Treaty program that aims to provide community engagement with bird-related recreation, education, and conservation. Bird City Network, created by American Bird Conservancy and Environment for the Americas, aims to build connections that lead to on-the-ground bird conservation. Audubon’s Bird-friendly Communities program tackles not only bird-friendly buildings, but also the importance of native plants for ensuring habitat availability for migrating birds.

Migratory birds are already in the midst of an extinction crisis, with nearly three billion birds lost in the U.S. and Canada since 1970. While improvements are being made on a city-by-city basis, the implementation of a nationwide framework could ensure some level of protection for migratory birds throughout the U.S. The Federal Bird Safe Buildings Act, reintroduced by Morgan Griffith (R-VA) and Mike Quigley (D-IL), is designed to make federal buildings more friendly. Various federal agencies have been incorporating bird-friendly measures into their buildings, such as installing bird-friendly glass and applying window treatments. Even homeowners can implement simple measures, such as closing blinds, to make a difference in local populations. Every effort is crucial to ensure that these birds can make it home safely.