Window stickers, which prevent birds from flying into the glass, are more efficient if they are attached to the outside of the pane, according to a new study. If these are attached to the inside of the glass, the animals usually cannot see them sufficiently, scientists at William & Mary’s Institute for Integrative Conservation in the US state of Virginia write in the journal PeerJ.
Often fatal
Birds are often unable to properly identify glass surfaces on buildings and then fly against them – which sometimes ends fatally. Stickers in the shape of birds or patterns on the glass surfaces are intended to prevent this, but are often attached to the inside for logistical and cost reasons. However, sticking them to the outside leads to a greater reduction in collisions and thus also in bird deaths, write the scientists.
On the outside
For the study, they tested various stickers and foils. Very fine nets were used to ensure that no birds were injured. “Many people want to prevent bird collisions with windows because these unfortunate occurrences kill millions of birds every year,” says author John Swaddle. “There are many decals and tints that are likely to make the glass surfaces more visible to birds and reduce the risk of collision. We have shown that people need to put these decals and tints on the outside of the windows for the birds to benefit.”