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The impact of free-ranging domestic cats on wildlife of the United States

Nature Communications volume 4, Article number: 1396 (2013) | Download Citation

  • A Corrigendum to this article was published on 12 December 2013


Anthropogenic threats, such as collisions with man-made structures, vehicles, poisoning and predation by domestic pets, combine to kill billions of wildlife annually. Free-ranging domestic cats have been introduced globally and have contributed to multiple wildlife extinctions on islands. The magnitude of mortality they cause in mainland areas remains speculative, with large-scale estimates based on non-systematic analyses and little consideration of scientific data. Here we conduct a systematic review and quantitatively estimate mortality caused by cats in the United States. We estimate that free-ranging domestic cats kill 1.3–4.0 billion birds and 6.3–22.3 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of this mortality. Our findings suggest that 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. Scientifically sound conservation and policy intervention is needed to reduce this impact.

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Change history

  • Updated online 12 December 2013

    The original version of this Article contained incorrect estimates of the number of animals killed by free-ranging domestic cats, which were based on 90% confidence levels rather than the stated 95% confidence levels. Reanalysis of the original data after publication using 95% confidence levels resulted in larger ranges for the estimated number of animals killed. The estimates have now been corrected throughout the PDF and HTML versions of the Article. Unrelated to the changes above, four estimates of cat predation rates on wildlife from temperate zone studies in Supplementary Table S1 were based on partial year values that had not been adjusted to year-round estimates. The values have now been revised in Supplementary Table S1.


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S.R.L. was supported by a postdoctoral fellowship funded by the US Fish and Wildlife Service through the Smithsonian Conservation Biology Institute’s Postdoctoral Fellowship programme. P. Blancher provided insight for development of the model of cat predation magnitude, and R. Kays, C. Lepczyk and Y. van Heezik provided raw data from their publications. C. Machtans facilitated data sharing, and participants in the 2011 Society of Canadian Ornithologists’ anthropogenic mortality of birds symposium provided context and perspectives. C. Lepczyk and P. Blancher provided comments on the manuscript. The findings and conclusions in this article are those of the authors and do not necessarily represent the views of the Smithsonian or US Fish and Wildlife Service. All data used for this analysis is available in the Supplementary Materials.

Author information


  1. Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, P.O. Box 37012 MRC 5503, Washington, District of Columbia 20013, USA

    • Scott R. Loss
    •  & Peter P. Marra
  2. U.S. Fish and Wildlife Service, Division of Migratory Birds, Midwest Regional Office, 3815 American Boulevard East, Bloomington, Minnesota 20013, USA

    • Tom Will


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S.R.L. designed the study, collected and analysed data, and wrote the paper. T.W. and P.P.M. designed the study and contributed to paper revisions. All authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Scott R. Loss.

Supplementary information

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    Supplementary Information

    Supplementary Tables S1-S3, Supplementary Methods and Supplementary References.

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