Wildlife Predation Issues

There is no doubt that feral cats play a major role in wildlife predation.  Because they are a non-native species, they can cause an unusual amount of damage to the natural ecosystems of Florida.  Read the articles below for proof positive that feral cats have a substantial negative impact on native wildlife:

The Impact of Free Ranging Domestic Cats on Wildlife of the United States. Nature (2013).

This new report from the Smithsonian and US Fish and Wildlife Service states in the abstract, “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 1.4–3.7 billion birds and 6.9–20.7 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.”

Read the full abstract (free) and/or purchase the full report at Nature.Com HERE.

Feline Geneticist Traces Origins of the Domesticated House Cat.  AP (2008).

This AP new report includes an excerpted interview with Dr. Leslie Lyons (University of California), the leader of a group of geneticists studying the origins of the domesticated house cat. When asked how cats got to America, she responds, “Cats spread through Asia, where they also became important to societies there: An all-white cat is considered good luck, for example. They came here, to North America, with the Pilgrims, on the boats to help with the rodent populations. There are no domesticated cats that are indigenous [native] to America or Australia; they all came over on boats.”

Read the interview here:  Origin of Domestic Cats

Impact of free ranging cats on birds in the United States.  Proceedings from the 4th Annual Partners in Flight Conference. (2008)

This paper discusses the incredible impact of free ranging cats on the bird populations of the US, stating “American birds face an estimated 117 to 157 million exotic predators in the form of free-ranging domestic cats (Felis catus), which are estimated to kill at least one billion birds every year in the United States. Cats have contributed to declines and extinctions of birds worldwide and are one of the most important drivers of global bird extinctions.”

Read the paper here:  Bird impacts_of_free_ranging_domestic_cats

The welfare of feral cats and wildlife.  JAVMA (2004)

This paper, written by one of the leading wildlife researchers in the field, makes very clear the impact of wildlife predation by feral cats.  Dr. Jessup observes, “Free-roaming and feral cats yearly kill hundreds of millions, perhaps as many as a billion, native North American birds, mammals, reptiles, amphibians, and fish.1,2 The Lindsay Museum of Walnut Creek, Calif, a full-service wildlife rehabilitation facility, received 5,669 small mammals, birds, and reptiles between January 1 and September 14, 2003. Of these, 24% (1,050) of birds, 12% (143) of mammals, and 15% (11) of reptiles were presented because of cat-related injuries or conditions.  These animals were brought in alive and do not include those that died or were not found. When raptors and pelagic birds are removed, accession figures reveal that 30.3% (1,015/3,353) of birds were admitted because of cat-related problems. This includes 36 species, many of which are songbirds or locally rare, sensitive, or migratory species; all are supposed to be protected by law from illegal take (Table 1). These figures are from 1 wildlife rehabilitation facility, which serves half of 1 small county in California, for < 9 months.”

Read the paper here: Jessup article on Wildlife impact javma


This paper, funded by the Fish and Game Department, shows the destruction feral cats have on native bird species.  This paper covers birds in five states, including Florida.  The authors note a, “2002 letter from the USFWS (to a Florida county regarding the Florida Scrub-Jay)…stated that these birds are, “particularly susceptible to being taken by cats because they inhabit low-growing vegetation, are highly territorial, and are relatively weak flyers.” The letter also states that, “the survival of scrub-jays in Brevard County is very important to the status of the species as a whole, and the continuing loss of scrub-jays to predation by feral cats could have dire consequences.”

Read the paper here:  Feral Cat impacts on Bird Species of Conservation concern

Toxoplasma gondii, Neospora caninum, Sarcocystis neurona, and Sarcocystis canis-like infections in marine mammals.  Journal of Veterinary Parasitology (2003).

This article demonstrates how T. Gondii is making its way into marine mammals.  The authors note, “More is known of T. gondii infections in sea otters because the parasite has been isolated from tissues of many naturally exposed sea otters and the serologic status has been verified with bioassay data (Cole et al., 2000; Lindsay et al., 2001; Miller et al., 2002a,b). T. gondii was isolated from brains or hearts from 15 of 67 (22.3%) sea otters by Cole et al. (2000) and 24 of 75 (32%) by Miller et al. (2002b). Antibodies to T. gondii were reported in 56% of 223 sea otters (Miller et al., 2002a). Toxoplasmosis has also been documented in Pacific harbor seals. Van Pelt and Dietrich (1973) first reported congenital toxoplasmosis in a 1-day-old seal and Miller et al. (2001b) isolated viable T. gondii from a diseased seal. Antibodies to T. gondii were found in 7.6% of 380 Pacific harbor seals by Lambourn et al. (2001).

Read the paper here:  Toxo in Marine Mammals including Manatees and Dolphins from Sarasota Peer Reviewed

Genetic Characterization of Feline Luekemia Virus from Florida Panthers.  CDC (2008).

This paper makes clear that domesticated cats can spread Feline Luekemia to the Florida Panther, one of our most endangered species.  As the abstract notes, “Genetic analysis of panther FeLV, designated FeLV-Pco, determined that the outbreak likely came from 1 cross-species transmission from a domestic cat.”

Read the paper here:  CDC Genetic Characterizations

“KittyCam” Reveals High Levels of Wildlife Being Killed by Outdoor Cats.  National Geographic Society (Aug 2012).

“A new study of house cats allowed to roam outdoors finds that nearly one-third succeeded in capturing and killing animals. The cats, which wore special video cameras around their necks that recorded their outdoor activities, killed an average of 2.1 animals every week they were outside, but brought less than one of every four of their kills home. Of particular interest, bird kills constituted about 13 percent of the total wildlife kills. Based on these results, American Bird Conservancy and The Wildlife Society estimate that house cats kill far more than the previous estimate of a billion birds and other animals each year.”

Read the full story with links to video here.

ABC Feral Cats and Wildlife Fact Sheet (2011).

This overview fact sheet, produced by American Bird Conservatory, highlights the destruction being caused by feral cats on native wildlife.  While this fact sheet focuses on birds, it also reveals huge numbers of kills of mammals and other small animals.

See the Fact Sheet:  ABC Cat Predation Fact Sheet 2011

Population Demography of Gray Catbirds in the Suburban Matrix.  Smithsonian. (2010)

This paper from the Smithsonian establishes the predation of stray and feral cats on the (rather ironically named) gray catbird.  The study shows a predation rate by the cat that is rather appalling.

Read the paper here:  Smithsonian 2010 Study on Gray Catbirds