So are the thoughts of vast numbers of cats, both domestic and feral, that are allowed to roam in nature.

A wide variety of studies have documented the impact of cats on birds and other small wildlife species.  In northern Georgia, “Kitty-Cams” mounted on free-roaming pet cats showed frequent predation on lizards, birds and small mammals, at a rate of 2.4 items each week. In Chicago, the abundance of cats is inversely correlated with the diversity of birds in suburban neighborhoods.

In the United States alone, cats are estimated to kill as many as 3 billion birds annually. Between 100 and 350 million more birds are killed by cats in Canada. Amongst the sources of mortality that birds suffer from humans, cats rank at the top of the list—above collisions with buildings (600 million birds/yr), automobiles (<340 million/yr), and wind turbines (340,000/yr).  When one considers habitat destruction for development, it is a wonder we have any birds at all.

If you are not one of the 60 million birdwatchers in the United States, why should you care?  The answer is not hard to find: birds perform a variety of services to human society, including predation on insect pests in croplands and forestry.  A variety of studies report higher levels of insects when birds are excluded from natural plant populations. Lizards also consume insects, as well as slugs and other garden pests.

Cats are exotic predators in North America. As such there has been little prior evolution by wildlife species here to avoid cat predation.  I don’t doubt that cats are wonderful pets, but I see no reason for cats to roam in nature.  It is not good for the cat and not good for wildlife.

Cat lovers advocate Trap-Neuter-and-Release (TNR) programs to control feral cat populations.  Since these programs return cats to the wild, they do little to relieve the problem. The only real solution is to eliminate feral and free-roaming domestic cats.  Many cat owners believe their “little mittens” couldn’t possibly be a killer. But, the Kitty-Cams never blink.

No cat should be allowed to roam free outdoors.

References

Belaire, J.C., C.J. Whelan, and E.S. Minor. 2014.  Having our yards and sharing them too: the collective effects of yards on native bird species in an urban landscape.  Ecological Applications 24: 2132-2143.

Blancher, P. 2013.  Estimated number of birds killed by house cats (Felis catus) in Canada.  Avian Conservation and Ecology 8:  doi: 10.5751/ACE-00557-080203

Loyd, K.A.T., S.M. Hernandez, J.P. Carroll, K.J. Abernathy, and G.J. Marshall. 2013.  Quantifying free-roaming domestic cat predation using animal-borne video camera.   Biological Conservation 160: 183-189.

Loss, S.R., T. Will, and P.P. Marra. 2013.  The impact of free-ranging domestic cats on wildlife of the United States.  Nature Communications 4: doi 10.1038/ncomms3961

Mantyla, E., T. Klemola and T. Laaksonen.  2011.  Birds help plants: A meta-analysis of top-down trophic cascades caused by avian predators.   Oecologia 165: 143-151.