Simpson
1
Courteney Simpson
Lecture Bio 102
Prof. Riggs-Shute
October 23, 2017
Cat vs. Bird Case Study
The article I chose to review is “The impact of free–ranging domestic cats on wildlife of
the United States” by Scott R. Loss, Tom Will, and Peter P. Marra. Predation by domestic pets
contribute to killing billions of wildlife annually. Domestic cats have contributed to multiple
wildlife extinctions on islands. “Free-ranging cats cause substantially greater wildlife mortality
than previously thought and are likely the single greatest source of anthropogenic mortality for
US birds and mammals.” (Loss, et.al)
Domestic cats were introduced by humans globally and are among the 100 worst non–
native invasive species in the world. The free-ranging cats on islands have caused 33 species of
the bird, mammal, and reptile extinctions. A non-scientific approach to manage free-ranging
cats would be to cause a mass extinction, however cats are not the biggest predators to the
Simpson
2
bird, mammal, and reptile populations. Collisions with man-made structures and habitat
destruction also play a large part in decline of the species. “Estimates of annual US bird
mortality from predation by all cats, including owned and un-owned cats, are in the hundreds
of millions.” (Loss, et.al)
An estimated 1.3-4.0 billion birds and 6.3-22.3 billion mammals are killed annually by
free-ranging domestic cats and un-owned cats cause the majority of the deaths. Approximately
2.4 billion is the average amount of birds killed by free-ranging domestic cats annually, while
