Every year, thousands of avid birders flock to important birding areas in the state of Michigan, hoping to see or hear a few of the millions of birds that are migrating to their breeding grounds. Birds migrate north to their breeding grounds mid-March through May; they then migrate south to their wintering grounds mid-August through October. Unfortunately, many migratory birds will meet an untimely death by colliding with window glass or other manmade structures; a phenomenon known as a bird collision or bird strike. It has been estimated that up to 1 billion bird-collision deaths occur every year in the U.S., according to the American Bird Conservancy. As humans continue to build structures that feature glass, the threat of increases in bird collisions will also continue.
Birds and humans have a different visual system. Glass is not visible to birds, and it becomes a deadly invisible barrier they are unable to avoid. Oftentimes as a result, birds will fly directly into windows, causing fatal injuries. In some cases, a bird will fly away after the collision, but it will likely succumb to its injuries elsewhere.
The good news is that there are many things we can do to prevent collision. Keep your windows dirty! Yes, dirty windows are good for birds. You can also use dark blinds on windows and keep your blinds shut. Consider moving plants away from windows without blinds to help prevent birds from trying to land on those plants. You can also move bird feeders: either place them within 3 feet of windows or more than 30 feet away from windows to prevent collisions. There are also a variety of window films that reduce reflection on the outside of windows; ABC (American Bird Conservancy) BirdTape can be hung vertically (4 inches apart), or horizontally (2 inches apart). The most common patterns on windows are spaced in a 4 inch by 4 inch, 4 inch by 2 inch or 2 inch by 2 inch pattern, the latter being the most effective. Companies and homeowners can also build Bird-friendly buildings by incorporating specially designed bird collision glass, and even minimizing the use of glass.
The Detroit Zoological Society believes it is important to take care of all birds, not just those that are cared for by the Zoo. The DZS has been committed to tracking and preventing bird collisions on Zoo grounds since 2013. All newly hired employees are required to attend an orientation program which includes how to recognize and report bird collisions to their supervisors. Bird department personnel also work to prevent bird strikes in a number of ways including the utilization of ABC BirdTape, custom CollidEscape window film and Feather Friendly dots.
The Polk Penguin Conservation Center and Buddy’s Pizza have specially designed “fritted” glass, and ORNILUX Bird Protection Glass was used in the giraffe building expansion. Detroit Zoo visitors have access to educational flyers and displays about bird collisions at various locations throughout the Zoo.
The Detroit Zoo would like to encourage the community to take preventative measures to protect wild birds from colliding with windows in their homes, schools and businesses. Also, participating in The Detroit Audubon Society’s“Project Safe Passage Great Lakes,” members of the community and property managers of high-rise buildings, apartments, and condominiums can turn off all building lights at night on unoccupied floors and spaces; lights left on in buildings overnight are a major cause of nighttime collisions that kill millions of birds.
We appreciate everyone who makes an effort to help protect wild birds!
– Bonnie Van Dam is the associate curator of birds for the Detroit Zoological Society.