Evaluating the Effectiveness of Select Visual Signals to Prevent Bird-window Collisions

Klem, D. E.; Saenger, Peter

doi:10.1676/12-106.1

Cited by 49 publications

(57 citation statements)

References 26 publications

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“…Their measure of density included counting the number of birds within 50 or less meters from the windows they monitored, but density is a meaningful explanation of the number of strikes if measured within 10 or less meters of a window surface, a vulnerable contact zone, where individuals of any species can be deceived attempting to reach habitat seen behind clear or reflected in mirrored panes. Although clear and reflective glass may be invisible to birds, the results of recent experiments reveal that alterations to the outside surface of windows, even with clear external films, offer enough visual cues to reduce the risk of a strike by 59% or more [20,21].…”

Section: Discussionmentioning

confidence: 99%

“…To prevent bird-window collisions and all their consequences, windows in the form of sheet glass and plastic must be transformed into barriers that diverse bird species will see and avoid. Notwithstanding skeptics [48,49], the most elegant solution, using UV signals that birds see and we humans do not has been shown to be an effective prevention method [20,21]. External films with effective prevention are not being manufactured because those with the know-how will not commit to production because they cannot factor in unconventional consumer interest into their business plan to determine if it merits their investment.…”

Section: Discussionmentioning

confidence: 99%

“…One German glass manufacturer has produced and sold a supposedly bird-safe pane using UV signals but reliable experimental testing of their windows revealed that they are ineffective, even more hazardous to birds than conventional glass. The interpretation of the inability of these panes to alert birds to their presence is that the UV signal is too weak (7%-22%) over the too narrow UV wavelength (300-400 nanometers) range, reaching above 20% UV-reflection only at 397 nm [21]. In comparison, previous studies found external films with UV-reflecting components of 20%-40% over 300-400 nm to effectively deter bird-window collisions [20,21].…”

Section: Preventionmentioning

confidence: 91%

“…Those that have been effective also limit viewing, but for those committed to protecting innocent potential victims the obstructed view is acceptable. Line and dot patterns that uniformly cover the entire pane and are applied in the form of ceramic frit or etching to surface #1 (facing outside environment) of a single or multi-pane window are most effective; they are less effective if applied to inner surfaces [20,21]. To completely eliminate collisions the dot and line patterns must be separated at most by 5 cm if oriented in horizontal rows, or 10 cm if oriented in vertical columns [4].…”

Section: Preventionmentioning

confidence: 99%

“…The interpretation of the inability of these panes to alert birds to their presence is that the UV signal is too weak (7%-22%) over the too narrow UV wavelength (300-400 nanometers) range, reaching above 20% UV-reflection only at 397 nm [21]. In comparison, previous studies found external films with UV-reflecting components of 20%-40% over 300-400 nm to effectively deter bird-window collisions [20,21]. Remarkably, although known for some time, no external film company has produced a product for retrofitting offending windows, nor has any glass manufacturer produced an effective bird-safe window using UV signals.…”

Section: Preventionmentioning

confidence: 99%

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Landscape, Legal, and Biodiversity Threats that Windows Pose to Birds: A Review of an Important Conservation Issue

Klem¹

2014

Land

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Windows in human residential and commercial structures in urban, suburban, and rural landscapes contribute to the deaths of billions of birds worldwide. International treaties, federal, provincial, state, and municipal laws exist to reduce human-associated avian mortality, but are most often not enforced for bird kills resulting from window strikes. As an additive, compared to a compensatory mortality factor, window collisions pose threats to the sustainability and overall population health of common as well as species of special concern. Several solutions to address the window hazard for birds exist, but the most innovative and promising need encouragement and support to market, manufacture, and implement.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Preventionmentioning

confidence: 91%

Section: Preventionmentioning

confidence: 99%

Section: Preventionmentioning

confidence: 99%

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Landscape, Legal, and Biodiversity Threats that Windows Pose to Birds: A Review of an Important Conservation Issue

Klem¹

2014

Land

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Causes, temporal trends, and the effects of urbanization on admissions of wild raptors to rehabilitation centers in England and Wales

Panter

Allen

Backhouse

et al. 2022

Ecology and Evolution

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Data from wildlife rehabilitation centers (WRCs) can provide on-the-ground records of causes of raptor morbidity and mortality, allowing threat patterns to be explored throughout time and space. We provide an overview of native raptor admissions to four WRCs in England and Wales, quantifying the main causes of morbidity and mortality, trends over time, and associations between threats and urbanization between 2001 and 2019. Throughout the study period, 14 raptor species were admitted totalling 3305 admission records. The Common Buzzard (Buteo buteo; 31%) and Tawny Owl (Strix aluco; 29%) were most numerous. Relative to the proportion of breeding individuals in Britain and Ireland, Peregrine Falcons (Falco peregrinus), Little Owls (Athene noctua), and Western Barn Owls (Tyto alba) were over-represented in the admissions data by 103%, 73%, and 69%, respectively. Contrastingly Northern Long-eared Owls (Asio otus), Western Marsh Harriers (Circus aeruginosus), and Merlin (Falco columbarius) were under-represented by 187%, 163%, and 126%, respectively. Across all species, vehicle collisions were the most frequent anthropogenic admission cause (22%), and orphaned young birds (10%) were most frequent natural cause. Mortality rate was highest for infection/parasite admissions (90%), whereas orphaned birds experienced lowest mortality rates (16%). For one WRC, there was a decline in admissions over the study period. Red Kite (Milvus milvus) admissions increased over time, whereas Common Buzzard and Common Kestrel admissions declined. There were significant declines in the relative proportion of persecution and metabolic admissions and an increase in orphaned birds. Urban areas were positively associated with persecution, building collisions, and unknown trauma admissions, whereas vehicle collisions were associated with more rural areas. Many threats persist for raptors in England and Wales, however, have not changed substantially over the past two decades. Threats associated with urban areas, such as building collisions, may increase over time in line with human population growth and subsequent urban expansion.

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What causes bird‐building collision risk? Seasonal dynamics and weather drivers

Scott

Danko²,

Plant³

et al. 2023

Ecology and Evolution

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Bird-building collisions are a major source of wild bird mortality, with hundreds of millions of fatalities each year in the United States and Canada alone. Here, we use two decades of daily citizen science monitoring to characterize day-to-day variation in building collisions and determine the factors that predict the highest risk times in two North American cities. We use these analyses to evaluate three potential causes of increased collision risk: heightened migration traffic during benign weather, increased navigational and flight errors during inclement weather, and increased errors in response to highly directional sunlight that enhances reflected images. The seasonal phenology of collisions was consistent across sites and years, with daily collision rates approximately twofold higher in autumn as compared to spring. During both migration seasons, collision risk was best predicted by the weather conditions at dawn. In spring, peak collision risk occurs on days with warm temperatures, south winds, and a lack of precipitation at dawn. In autumn, peak collision occurs on days with cool temperatures, north winds, high atmospheric pressure, a lack of precipitation, and clear conditions with high visibility. Based on these results, we hypothesize that collisions are influenced by two main weather-driven mechanisms. First, benign weather at dawn and winds that are favorable for migration cause an increase in migration traffic in both spring and autumn, creating greater opportunity for collisions to occur.Second, for autumnal migrants, cold clear conditions may cause an additional increase in collision risk. We propose that these conditions may be particularly hazardous in autumn because of the high abundance of naïve and diurnal migrants at that time of year. Our analysis also establishes that a relatively small proportion of days (15%) are responsible for 50% of the total collision mortality within a season, highlighting the importance of targeting mitigation strategies to the most hazardous times.

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Evaluating the Effectiveness of Select Visual Signals to Prevent Bird-window Collisions

Cited by 49 publications

References 26 publications

Landscape, Legal, and Biodiversity Threats that Windows Pose to Birds: A Review of an Important Conservation Issue

Landscape, Legal, and Biodiversity Threats that Windows Pose to Birds: A Review of an Important Conservation Issue

Causes, temporal trends, and the effects of urbanization on admissions of wild raptors to rehabilitation centers in England and Wales

What causes bird‐building collision risk? Seasonal dynamics and weather drivers

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