PRESSING ISSUES ACTION PLAN Completed by Pressing Issues Working Group for the Idaho Bird Conservation Partnership September 2013 Issue: Impacts of roaming, stray, and feral domestic cats on birds Background: Domestication of the cat (Felis catus) took place about 9,000 years ago from the Near Eastern wildcat (Felis sylvestris lybica; Medina et al. 2011). Domestic cats are now widely distributed across the globe from the sub Arctic to the tropics (Bonnaud et al. 2011). Domestic cats, and particularly feral cats, pose a grave threat to native species. Feral cats have impacted insular endemic birds and mammals and have caused local extinction of island breeding seabirds (see reviews in Bonnaud et al. 2011 and Medina et al. 2011). Prey species on continental landmasses have co-evolved with predators, including the domestic cat, for millennia and are considered less susceptible to cat predation (Tschanz et al. 2011). However, estimated losses of wild birds to cat predation within the continental US are over 1 billion birds/year (Loss et al. 2013). Recent declines in many farmland and garden birds, and high densities of domestic cats in such areas, have led to a focus on the ecological role of the cat as a predator in these landscapes (Tschanz et al. 2011). Gardens have become increasingly important, functioning as wildlife refuges in fragmented landscapes, in the face of increased urbanization. Roaming, stray, and feral domestic cat populations may have different impacts on their environment and pose different conservation risks (Kays and DeWan 2004). Roaming domestic cats, living as pets with humans, are generally well-fed and receive veterinary care, and although their overall impacts to bird populations remains unclear, recent studies indicate that previous estimates of impacts have been significantly underestimated (Loss et al. 2013, Loyd et al. 2013). Feline pets prey on birds, and even when they do not physically kill birds, just their brief presence can significantly reduce avian fecundity by causing a change in provisioning behavior and increasing exposure to other predators (Bonnington et al. 2013). Farm/ranch cats, and cats that live in cat colonies consisting mostly of neutered strays, are also partially or fully subsidized by humans. Truly feral cats receive little or no food from humans and hunt to obtain food (Kays and DeWan 2004), and can have a continent-wide ecological impact, as has been shown for Australia where introduction of the domestic cat and establishment of feral cat populations has a significant effect on the native fauna and a substantial number of continental mammal extinctions (Kutt 2012). The domestic cat population in the U.S. is estimated at about 90 million and the number of unowned (feral) cats between 10-50 million. The world population of domestic cats was estimated at about 400 million in 1990 (Jarvis 1990). Domestic cat densities in urban or suburban areas can be extremely high, locally reaching densities of >200 cats/km 2 (Baker et al. 2011). This density is many times higher than those of naturally occurring mammalian mesopredators (e.g., skunk or red fox). Annual predation rates of domestic cats on wildlife, including birds, reported in the literature vary considerably from as low as 21 (Baker et al. 2005) to as high as 1
125/prey/cat (Loyd et al. 2013). Interestingly, one study (Tschanz et al. 2011) reported that 16% of domestic cats in their study population accounted for 75% of prey taken. A recent estimate by Loss et al. (2013) suggests that cats are responsible for the deaths of up to 3.7 billion birds and 20.7 billion mammals annually in the U.S., with feral and stray cats being the worst offenders. Control of feral cat populations, particularly in urban environments is problematic. These cats occur in densities 10-100 times higher than similarly sized native predators and have been shown to impact native bird populations (e.g., Hawkins 1998). During the past 5-10 years, support for a new movement called the trap-neuter-return (TNR) method has grown. Feral cats are trapped, sterilized and released to the environment to be fed and cared for by volunteers. Supporters of this approach claim that such cats do not harm wildlife; fill a natural or realized niche; do not contribute to the decline of native species; are an insignificant vector or resource of disease; and that colonies of feral cats will be eventually eliminated by TNR (Longcore et al. 2009). None of these claims are supported by scientific literature. Feral cats and feral cat colonies present a clear and present danger to native wildlife through high levels of depredation; impact populations of native species; are significant vectors of infectious diseases; and TNR methods do not eliminate or even decrease population size of feral cat colonies (Longcore et al. 2009). According to their critics, the ultimate goal of TNR is to recognize and treat feral cats as protected wildlife. Proposed Actions: We recommend adopting actions identified by The Wildlife Society s position paper on feral and free-ranging domestic cats (http://joomla.wildlife.org/documents/positionstatements/28- Feral%20&%20Free%20Ranging%20Cats.pdf). These policy statements approved by TWS Council in August 2011, are presented in the following. 1. Support and encourage the humane elimination of feral cat populations, including feral cat colonies, through adoption into indoor-only homes of eligible cats and humane euthanasia of unadoptable cats. 2. Support the passage and enforcement of local and state ordinances prohibiting the feeding of feral cats, especially on public lands, and the release of unwanted pet or feral cats into the wild. 3. Oppose the passage of any local or state ordinances that legalize the maintenance of "managed" (trap/neuter/release) free-ranging cat colonies. 4. Support educational programs and materials that provide scientific information on feral cats and the negative effects on cats from living outdoors, and call on pet owners to keep cats indoors, in outdoor enclosures, or on a leash. 5. Support programs to educate and encourage pet owners to neuter or spay their cats, and encourage all pet adoption programs to require potential owners to spay or neuter their pet. 6. Support the development and dissemination of information on what individual cat owners can do to minimize predation by free-ranging cats, and to minimize potential disease transmission to humans, wildlife, cats, and other domestic animals. 7. Pledge to work with the conservation and animal welfare communities to educate the public about the effects of free-ranging and feral cats on native wildlife, including birds, small mammals, reptiles, amphibians, and endangered species. 2
8. Support educational efforts to encourage the agricultural community to keep farm-cat numbers at low, manageable levels and use alternative, environmentally safe rodent control methods. 9. Support efforts to reduce risks to the health of humans and other animals posed by diseases and parasites of feral cats, including but not limited to removal of free-ranging cats and elimination of feral cat colonies. Encourage researchers to develop, obtain, and disseminate information on the impacts of feral and free-ranging cats on native wildlife populations, relative to predation, competition, and diseases. 10. Recognize that cats as pets have a long association with humans, and that responsible cat owners are to be encouraged to continue caring for the animals under their control. Working Group Roles: Outreach, Education, and Citizen Science Working Group most appropriate to take the lead for addressing this issue. Specifically, this Working Group should concentrate on implementation of the policies that are adapted by the TWS Council regarding feral and free-ranging domestic cats. Also, likely a role for helping to coordinate other conservation-focused groups in the state, including local Audubon chapters, etc. IBCP Steering Committee may be appropriate for addressing Action Items #2 and #3 if a letter is needed stating the IBCP s position on this issue. Monitoring and Research Working Group may become involved to track scientific literature on feral and domestic cat impacts to native wildlife to support the Outreach, Education, and Citizen Science Working Group. Funding Working Group may become involved if it is determined that funding is needed for dissemination of information regarding feral and free-ranging domestic cats. Pressing Issues Working Group will be responsible for tracking and reporting success (outlined below) to the IBCP Steering Committee and general membership as appropriate. Measures of Success: 1) Have educational programs or materials been developed and/or distributed that provide scientific information on feral cats and the negative effects on cats from living outdoors, and call on pet owners to keep cats indoors, in outdoor enclosures, or on a leash? 2) Has IBCP been successful in deflecting or defeating the passage of any local or state ordinances that legalize the maintenance of "managed" (trap/neuter/release) free-ranging cat colonies? 3) Have any local and state ordinances been passed prohibiting the feeding of feral cats, especially on public lands, and the release of unwanted pet or feral cats into the wild? 4) Have educational materials been developed and/or distributed to the conservation and animal welfare communities to educate the public about the effects of free-ranging and feral cats on native wildlife, including birds, small mammals, reptiles, amphibians, and endangered species? 3
5) Have educational materials been developed and/or distributed to the agricultural community to keep farm-cat numbers at low, manageable levels and use alternative, environmentally safe rodent control methods. Pressing Issues Group Main Contact for this Issue: Name: Colleen Moulton Email: colleen.moulton@idfg.idaho.gov Phone: 208-287-2751 Literature Cited Baker, P. J., A. J. Bentley, R. J. Ansell, and S. Harris. 2005. Impact of predation by domestic cats Felis catus in an urban area. Mammal Review 35:302-312. Bonnaud, E., F. M. Medina, E. Vidal, M. Nogales, B. Tershy, E. Zavaleta, C. J. Donlan, B. Keitt, M. Le Corre, and S. V. Horwath. 2011. The diet of feral cats on islands: a review and a call for more studies. Biological Invasions 13:581-603. Hawkins, C. C. 1998. Impacts of subsidized exotic predator on native biota: effect of house cats (Felis catus) on California birds and rodents. Ph. D. thesis. College Station, Texas A&M University, College Station, Texas. Kays, R. W., and A. A. DeWan. 2004. Ecological impact of inside/outside house cats around a suburban nature preserve. Animal Conservation 7:273-283. Kutt, A. S. 2012. Feral cat (Felis catus) prey size and selectivity in north-eastern Australia: implications for mammal conservation. Journal of Zoology 287:292-300. Longcore, T., C. Rich, and L. M. Sullivan. 2009. Critical Assessment of Claims Regarding Management of Feral Cats by Trap-Neuter-Return. Conservation Biology 23:887-894. Loss, S. R., T. Will, and P. P. Mara. 2013. The impact of free-ranging domestic cats on wildlife of the United States. Nature Communications4: 1396. 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 cameras. Biological Conservation 160:183-189. Medina, F. M., E. Bonnaud, E. Vidal, B. R. Tershy, E. S. Zavaleta, C. J. Donlan, B. S. Keitt, M. Le Corre, S. V. Horwath, and M. Nogales. 2011. A global review of the impacts of invasive cats on island endangered vertebrates. Global Change Biology 17:3503-3510. Nogales, M., A. Martin, B. R. Tershy, C. J. Donlan, D. Witch, N. Puerta, B. Wood, and J. Alonso. 2004. A review of feral cat eradication on islands. Conservation Biology 18:310-319. 4
Ruxton, G.D., S. Thomas, and J. W. Wright. 2002. Bells reduce predation of wildlife by domestic cats (Felis catus). Journal of Zoology 256:81-83. Tschanz, B., D. Hegglin, and S. Gloor. 2011. Hunters and non-hunters: skewed predation rate by domestic cats in a rural village. European Journal of Wildlife Research 57:597-602. Woods, M., R. A. McDonald, and S. Harris. 2003. Predation of wildlife by domestic cats Felis catus in Great Britain. Mammal Review 33:174-188. 5