More than a billion birds die every year in the U.S. after colliding with buildings, a new study estimates.
Researchers found 60% of birds taken to animal hospitals after hitting a building either die or must be euthanized. This conflicted with earlier assumptions that most birds that initially survived hitting a building would later recover. The new findings helped push the estimates of total deaths due to building collisions higher.
Experts say birds have no concept of the glass windows of buildings, which may appear to them as continued open space or may reflect nearby green space. Territorial birds may also perceive reflections as threats and engage them accordingly. The amount of glass in a building, the size of the building and even the proximity of domestic bird feeders to windows have all been shown to affect the total number of collisions.
The new estimate makes buildings one of the leading killers of birds in the country, behind only cats, which according to the U.S. Fish and Wildlife Service kill an estimated average of 2.4 billion birds per year.
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Experts say we should do more to prevent bird collisions in the first place, whether by turning off lights that might disorient birds at night, or installing window markers or bird screens.
"We cannot rely on only rehabilitation to fix this kind of problem," said Ar Kornreich, the study's lead author. "The best medicine is absolutely prevention because some of these injuries just have really bad prognosis."
