#science numbers: How many #birds are killed in the US every year? A lot.

From the Acopian Center for Ornithology at Muhlenberg College:

Before much was known, annual deaths attributable to windows were hypothesized to be 3.5 million in the 1970s. Since then, extensive studies over the past three decades have been used to estimate the annual toll to be between 97 million to 975 million birds in the U.S. alone. The wide-ranging difference among these figures attests to the complexity of attempting to determine accurate amounts from a source in which every individual bird is a potential victim and sheet glass of every size is a potential killing site in the environment. The roughly 100 million to 1 billion toll is based on the assumption that 1-10 birds are killed at one building in the U.S. each year. Another independent study produced similar results, and evaluated this current range of annual mortality figures to be reasonable. This confirming study examined records of 5,500 volunteers who optionally recorded bird strikes at windows while they counted visitors to feeding stations at their homes. To put these numbers in perspective, annual U.S. bird populations are estimated to be 20 billion in the fall, and annual glass kills are estimated to be 0.5 to 5.0% of this figure.

That is a significant proportion. I feel guiltier than I expected.

By comparison, each year U.S. hunters are estimated to take 120.5 million birds, and free-ranging domestic cats are suspected to kill hundreds of millions to over a billion songbirds.

Cats are bastards.

Some researchers suggest that the overall avian mortality attributable to glass is likely to be much greater than what is attributable to cats: reasoning that cats are active predators that most often capture vulnerable prey while sheet glass is an indiscriminate killer that takes the strong as well as the weak and is astronomically more numerous than cats.

Apparently, windows are also bastards.

Minimally, from an ethical and moral perspective, any unintended and unnatural killing associated with human presence in the environment should be addressed and reduced if not eliminated. Guilt and anxiety are common feelings among an increasing number of people who discover an accidental fatality beneath the window of their home, workplace, or any other structure.

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