Glass pane markings to prevent bird-window collisions: less can be more

Abstract

To prevent birds from collisions with glass, markings on glass panes can be a valuable measure. However, to ensure public acceptance and widespread use of glass markings, maximum deterrent effect at minimum area covered has to be achieved. In this study we show that the efficacy of a deterring pattern does not necessarily depend on the size of the surface area of the marking but on orientation, spacing and dimension of the marking elements. We examined achromatic marking patterns in 1,428 choice experiments with wild birds (mostly songbirds) in a flight tunnel of seven meters length. A mist net ensured that the birds suffered no injury. Twelve markings were tested; of these, eleven effectively reduced collisions. However, considerable differences existed among the tested patterns. Covering less than 7%, 2 mm wide stripes were as effective as 13 mm wide stripes covering 50% of the glass surface. Vertical stripes 10 cm apart were significantly more effective than the same pattern in horizontal orientation. To create bird protection markings on glass, designers should consider both perceptional limits and pattern related behavioural responses of birds.

Relationship between bird-of-prey decals and bird-window collisions on a Brazilian university campus

“…However, based on previous studies in the northern hemisphere (e.g. Klem 1990, Rössler et al 2015 we predict that bird-of-prey shaped decals will be ineffective at reducing the number of bird-window collisions and that it is independent of season. We also estimate which species are prone to window collisions.…”

“…He also found the largest reductions were associated with the application of horizontal or vertical stripes in a rectangular mesh. In Europe, Rössler et al (2015) tested several methods using achromatic patterns and found that 2mm-wide stripes covering < 7% of a window were as effective as stripes of 13mm covering half of pane at reducing collisions. He also found that 10 cm long vertical stripes were more effective than horizontal stripes of the same size.…”

“…Based on this, an effective protocol could be developed to incorporate the testing of a various interventions. This would include decals separated by up to 10cm (Klem 2009b, Ocampo-Peñuela et al 2016b), 10 cm x 2 mm vertical stripes (Rössler et al 2015) and avoiding "ecological traps", such as bird feeders near glass windows (Klem 1990, Klem et al 2004, Krummer and Bayne 2015 in an effort to reduce collisions. The main goal would be to create a signal of any kind that allows birds to detect and avoid windows (US Fish and Wildlife Service 2016).…”

“…Several methods have been proposed in the Northern Hemisphere in an effort to reduce bird-window collisions, including both 2D adhesive decals and 3D mobiles simulating birds of prey, wind bells, flashing lights, UV markings and paintings, and stripes (Klem 1990, Klem and Saenger 2013, Oviedo and Menacho-Odio 2015, Rössler et al 2015. In Brazil, adhesive bird-of-prey decals are sparsely applied to glass windows in cities and parks throughout the country but without standardization and unknown effectiveness.…”

Reducing avian mortality from noise barrier collisions along an urban roadway

“…Transparent barriers constructed along roadways to reduce or block traffic noise can be especially lethal to birds (Coffin 2007;Loss et al 2014;Morelli et al 2014;Rössler et al 2015), and several studies have investigated how to prevent collisions between birds and clear and reflective panes (Klem 2006(Klem , 2009. The use of marks with various patterns visible to birds and humans are known to be an effective collision prevention method (Rössler et al , 2009(Rössler et al , 2015Schmid et al 2013).…”