A study of 500 species of birds in Canada and the US was published in the prestigious journal Science in September 2019. It found that in the last 50 years, 3 billion birds have disappeared. This is 29 percent of the number of birds in the 500 species surveyed.
We are part of the causes. Over one year, our activities were involved in killing 1,768 million birds in Canada and the US. Household cats killed 764 million of those. Building strikes killed 624 million, cars killed 213 million, power lines killed 55 million and there were 7 million killed by other causes. Causes of mortality other than household cats total 899 million. Household cats killed 764 million — almost as many birds as all other recorded causes and this does not include birds killed by feral (non-owned) cats. (More details in National Geographic, Oct. 2019.)
We certainly could correct some of these causes of bird killings. Clearly the single most effective and least costly action would be to prevent killing of birds by household cats.
Written by: Gray Merriam