Feral Cats — Scourge of Birds?

I love cats. I had them the whole time I was growing up, and I wish I had one now, but it just wouldn’t work. And my cats have always been at least partially outdoor cats. I never thought about it too much, and my mother firmly believes that it is wrong to keep a cat indoors all the time, for the cat’s sake. But this article has made me really think about that theory.

Apparently, according to this Audubon article, cats, both totally feral and those somewhat dependent on humans, kill millions of birds a year.

The American Bird Conservancy estimates that 150 million free-ranging cats kill 500 million birds a year in the United States.

Many people believe that Trap, Neuter, Return (TNR) is the answer. Feed the feral cats, trap them, neuter them, and then return them. But apparently it doesn’t work.

According to a peer-reviewed study published February 24, 2009, in Conservation Biology, TNR causes “hyperpredation,” in which well-fed cats continue to prey on bird, mammal, reptile, and amphibian populations so depressed they can no longer sustain native predators.

The article focused mainly on Hawaii, an area of particular concern because of the many indigenous and unique bird species there that are threatened with extinction, but the points made also apply to the mainland, too, Wisconsin and Florida being cited in particular.

Honestly, I knew cats kill birds, but I never thought the problem could be so terrible. And I never thought about this:

Wildlife biologists and law-enforcement officials contend that in most situations feeding feral cats violates federal law because it facilitates “take” of species protected by the Migratory Bird Treaty Act and/or the Endangered Species Act.

But that isn’t usually enforced, due to the power of the feral cat lobby.

Last year, for example, it squashed federal legislation to remove exotic species from national wildlife refuges because feral cats might be among them. In Hawaii legislation to ban the feeding of cats on state property is invariably shouted down. “TNR advocates are very well organized and funded,” declares Steve Holmer, director of public relations for the American Bird Conservancy. “They’re getting ordinances passed all over the place.”

The article was fascinating, and contains much more data and facts than I am providing here. I highly recommend reading the whole article. What do you think? Should all cats be caged or kept indoors? Why doesn’t TNR work? It seems like it should: sterilize the cats in a colony, and natural causes of death should do the rest. Is it impossible to trap all the cats in a colony? Does in-migration to a food source bring in unneutered cats?

cross-posted at Citizens for Sustainability

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  1. TNR does work, please check out Alley Cats Allies for a list of studies done on TNR: http://www.alleycat.org/NetCommunity/Page.aspx?pid=668

    Human caused habitat destruction is the major cause of bird numbers decline. Even if all the feral cats were eliminated and all domesticated cats were kept indoors, bird numbers would continue to decline. Audubon published a paper called “Common Birds in Decline” 2007. In it they stated that the reasons for declining bird numbers as intensified farming techniques, logging, urban sprawl, industrial development, pesticides and loss of wetlands. The paper did not mention cats! Audubon does recommend using the CatBib, a product that stops 4 out of 5 cats from killing birds.(Audubon magazine, Jan-Feb 2008)

    Cats are an easy emotional target, good for fund raising. The American Bird Conservancy knows all about the CatBib, but will not acknowledge it exists for fear it will dilute their (tax funded campaign) message “Keep Cats Indoors”. The CatBib has the potential to save millions of birds if only more people knew about it.

    Window collisons by birds is the second major killer of birds, by 10 times. Prof. Daniel Klem, Jr. estimates one billion birds are killed by “window strikes” per year in the US alone.

    Prof. Michael Calver had this to say “(Cat) predation may not be a major cause of wildlife decline in suburbia although it is a convenient scapegoat. Attention to other issues such as housing density, road design and retention and management of remnant native vegetation may bring greater benefits….”

    There is so much more to this subject….I do hope you look into it further. Wildlife would have tremendous advocates if cat people and bird people would join forces.

    • I found out about the Cat Bib after writing the post — Audubon did not mention it in the print version, only at the bottom of the online version. I was meaning to write another post about the cat bib, but hadn’t gotten to it yet! My main goal here was to start a discussion — thank you!

  2. Brenda Pike

     /  October 20, 2009

    I definitely think cats should be inside, not just for the birds, but for their own welfare. My parents’ outdoor cat lived to be 15, but my sister has lost two kittens in a row because she let them outdoors. My own two cats will always be indoor-only.


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