Groundbreaking new research in the field of bird/window collisions shows that past estimates of mortality are significantly underrated, according to the peer-reviewed article “Evidence, consequences, and angle of strike of bird–window collisions” published in The Wilson Journal of Ornithology.

The researchers found that 50 percent of bird/window collisions left no measurable evidence of a strike, and as many as 70 percent of the stunned victims likely succumbed from the collision. Therefore, estimated annual mortality may be minimally 1.28 billion–3.46 billion or as high as 1.92 billion–5.19 billion in the United States, with potentially billions more worldwide.

The researchers used direct observation to record what, if any, evidence was measurable when a bird hit the outside surface of plate glass during field experiments to evaluate several products meant to deter window strikes.

The article is co-authored by Daniel Klem, professor of ornithology and conservation biology and director of the Acopian Center for Ornithology at Muhlenberg College, Acopian Ornithological Specialist Peter G. Saenger and former student researcher Brandon P. Brogle.

While spring migration is happening now, Klem’s previous research shows that the majority of collisions occur year-round, and not only during the migratory periods. According to related research, low-rise commercial buildings (four stories or less) account for the greatest number (54%) of bird-glass deaths, followed closely by residential homes (45%) mortality. While Lights Out programs are important for bringing attention to bird-window collisions, as well as saving energy and preserving our night skies, only 1 percent of collisions occur at high-rise buildings.

To view the full article, for additional information or to schedule an interview, contact Dr. Daniel Klem at danielklem@muhlenberg.edu, Peter Saenger at petersaenger@muhlenberg.edu or Kristine Yahna Todaro at kristinetodaro@muhlenberg.edu.

How to prevent bird deaths:

• Make glass visible to birds using stickers, strings or film in a 2 inch by 4 inch pattern. Other DIY and affordable options for homeowners and renters include closing blinds and keeping screens on windows year round. • For new construction or replacement windows, current options include acid-etched and fritted glass and many other visible patterns to reduce collisions. Select manufacturers currently have, and others are developing, new solutions using ultraviolet (UV) patterns to determine whether UV alone can be an effective deterrent to collisions.

• Advocate! While the actions of individuals make a difference, larger-scale efforts are needed to save birds from this fate. Klem says we can achieve this by working together to influence city, state and federal governments to require bird-protective legislation and building requirements.

• VIDEO: “Bird’s Eye View: Avoiding Bird/WIndow Collisions” at https://www.youtube.com/watch?v=_gJmBLFnAa4

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