Indoor Cat Birdwatching

A recent study by the Smithsonian Institution and the US Fish and Wildlife Service estimated that domestic cats kill about 2.4 billion birds and 12.3 billion small mammals each year in the lower forty-eight states.  This is far higher—and probably more accurate–than previous figures, and likely exceeds all other sources of human-related losses of these animals.  That makes it a major bird conservation concern.

These deaths occur because our nation has a whole lot of cats–about 85 million owned and perhaps 55 million non-owned, or feral, cats.  Assuming that California has cats in proportion to its share of the nation’s population, it supports about 20 million, who kill about 300 million birds each year.  A similar extrapolation puts the loss at 1.5 million each year in Yolo County.  These numbers contradict a common attitude that bird losses to cats are negligible compared to other threats, so there is no need to worry about them.   

The study pointed to some ways to reduce bird predation by cats.  It found that cats kill birds in proportion to how much time they spend outdoors; so keeping your cat inside helps a lot.  On the other hand, feeding cats has no effect on their predation rate; so setting out food for feral cats is no help.  Seventy percent of the killing is by the roughly forty percent of cats that are feral; so taking unwanted cats to the County animal shelter in Woodland is much better than abandoning them on the roadside.

The study concluded that programs to trap, neuter, and return feral cats to the wild fail to help reduce their numbers.  This is largely because far too small a fraction of the feral population gets treated.  Some animal welfare organizations see it differently.  For example, the website of the Yolo County SPCA includes a solicitation for donations to its trap-neuter-return program, arguing that it is more humane than euthanizing unwanted cats.   

Given the importance of this topic for bird life, Yolo Audubon intends to explore it further in the coming months.  In the meantime, visit the website of the American Bird Conservancy for more information, and to read the study cited in this article.

Michael Perrone, YAS Conservation Chair