Regarding the letter [“Learning the Ways of the Wild,” Sept. 26] disputing the numbers of songbirds killed by feral and free-ranging cats (indoor cats allowed free access to the outdoors) discussed in my letter [“Revisiting Those Cats and Snakes,” Sept. 12], I would agree with the writer to the extent that there is an absence of studies that have accurately determined the extent of songbird mortality from free-ranging and especially feral-cat predation. (Obviously, these types of studies are very difficult to conduct.)
However, there are several studies (including a study by University of Wisconsin ornithologist Dr. Stanley Temple, that estimated between 20 million and 150 million songbirds are depredated yearly by rural cats in Wisconsin alone) that have determined that the impact of cat predation on songbird populations is quite extensive. Another study of free-ranging cats belonging to landowners that resided in breeding-bird survey routes (120 kilometers) in southeastern Michigan has conservatively estimated that between 16,000 and 47,000 birds are depredated (doesn’t include predation by feral cats) during the breeding season.
While the actual number of songbirds predated by cats is difficult to accurately determine, it is no urban myth that over 100 million free-roaming and free-ranging cats exist in this country. The previously mentioned Michigan study (“Landowners and Cat Predation Across Rural-to-Urban Landscapes,” Biological Conservation) estimated that, on average, these cats depredate one bird a week. Doesn’t seem too difficult to do the math and come up with some enormous numbers.
Just as with global warming, there’s a lot of controversy over this subject. Considering the risks that these cats pose to the native wildlife populations, it seems pretty obvious, at least to me, that we should be taking steps to minimize these risks before the problem gets even worse, instead of arguing about the numbers. Even the naysayers (I would hope, anyway) would have to say that there is a problem.
— Jeff Smith