Multifamily buildings can be strikingly beautiful with shiny glazing, often geometric architecture, and towering levels. Yet, the impact reflective or transparent windows can have on birds in flight is detrimental.
An estimated 365 million to 988 million birds are killed annually by building (of all heights) collisions, according to a study from the U.S. Fish and Wildlife Service and the Smithsonian Institution in 2014. However, this number does not account for the birds that fly away after collision but ultimately die or are taken to rehabilitation centers where they often succumb to injuries.
To befriend the birds, simple retrofitting of existing facades or adhering to the American Bird Conservancy’s (ABC) Bird-Friendly Building Standard for new construction can help. ABC considers a bird-friendly building to start with at least 90% of the material of the exposed façade from ground level to 40 feet, which is the primary collision zone, to have a threat score of 30 or less.
Tapping architect Kate Scurlock, senior associate at GWWO Architects, which specializes in cultural and educational projects that are predominantly bird-friendly, MFE learned more on features architects and developers can implement to help the feathered friends.
What are ways developers and architects can deter birds from colliding with buildings?
Bird-friendly architecture is designed to be a visible barrier to birds. The biggest threat to birds is transparent glazing, as birds cannot detect that glass is a barrier. Therefore, by eliminating clear glazing from high- (and low-) rise buildings, we can drastically reduce bird collisions.
There are many options on the market for glazing that is visible to birds, which can be easily integrated into traditional curtain wall or storefront framing systems. Other best practices for bird-friendly architecture include reducing exterior or landscape lighting and utilizing dark sky compliant fixtures.
Are there any specific designs that have been proven to help?
Patterned glass (acid-etched or ceramic frit) that satisfies the 2-inch-by-4-inch rule from The Acopian Center for Ornithology at Muhlenberg College and the American Bird Conservancy, which shows that most birds will not attempt to fly through horizontal spaces less that 2 inches high or vertical spaces 4 inches wide or less. These can be dot patterns, stripe patterns, or a unique/custom design. They perform best when installed on the No. 1 (exterior most) glass surface. An example of this is the Bird1stEtch or AviProtekE.
Another option is UV patterned glass, which are patterns that are almost invisible to humans but visible to birds, or opaque or frosted glass. Additionally, netting or screening can be installed outside of glazing.
How can owners/managers of existing buildings alter properties to be more visible for birds in flight?
There are many retrofit options for glazing to create a visible barrier. Most popular retrofit options are utilizing film or decals applied to glazing. Building managers can monitor collisions to understand where most collisions are happening and can treat that glazing first. Often, certain facades suffer more collisions than others depending on orientation and adjacent landscaping.
What misconceptions do you often hear surrounding bird-friendly architecture?
That bird-friendly design is more expensive. With more and more options coming into the market for bird-friendly glazing and increased requirements to reduce solar heat gain, many of the glazing options support both initiatives and are available for a limited (if any) premium.
Another misconception is that bird-friendly design is not aesthetically pleasing. Bird-friendly glazing can be functional and beautiful, it can help to tell a story or create a unique visual appearance. There are also options that humans don’t perceive (UV glazing options).
