Pablo Picasso, 1939 Look what the cat dragged in! Wildlife in a world of Domestic Predators Kerrie Anne Loyd, PhD Arizona State University Colleges at Lake Havasu
History of Cats Felis catus domesticated in middle East from Felis silvestris (Wade 2007) control pest rodents in agricultural regions Brought to US with European settlers (not a native component of our systems) Perceptions have changed over time, once worshipped by Egyptians, associated with witchcraft to intelligent companions today
Everybody s Cats Most popular pet >86 million owned pet cats in US (APPA 2012) 45-77% allowed outdoors (APPA 1997, Crooks and Soule 1999, Kays and DeWan 2004, Loyd and Hernandez 2012) Similar in Australia and New Zealand
Cats, Cats and More Cats # stray cats in US unknown but expected to rival the number of owned cats 30 min - 80 million (Loss et al 2013) many in urban/suburban areas densities 10-100x higher than native predators (Liberg 2000) 1500 cats/km 2 in urban areas of the UK (Jones 2013) 2000 cats/km 2 in sites in urban Rome, Jerusalem (Liberg 2000)
Cats, Cats and More Cats Non-native predators thought to pose a significant threat to wildlife (Crooks and Soule 1999, Baker et al 2008, van Heezik et al 2010) Hunt instinctively even if well fed (Davis 1957, Adamec 1976) Potential to impact ecosystems recognized over 150 years ago (Darwin 1859)
Birds driven to extinction by cats Stephen s Island Wren (NZ) Socorro Island Dove (MX) 14% of extinctions on islands 33 total species (Nogales et al 2004) Guadalupe Storm Petrel (MX)
Bird populations decimated by cats Sooty Tern (Ascension Island, UK) Socorro Mockingbird (MX) Island ground nesting seabirds and burrow nesting seabirds are most vulnerable (Nogales et al 2004) Mainland populations understudied Fragmented habitats (suburban areas) are islands Ground foraging species in suburban areas most susceptible (Cooper et al 2012) Blackvented Shearwater (MX)
Cats Kill Wildlife
Pet Cats Kill Wildlife predation studies measured prey returned to residences by owned cats Cats don t bring all prey home (Kays and DeWan 2004) Most research took place abroad Average annual prey Number of per hunting cat cats studied Location Reference 14.4 10.2 56 54.6 27.1 21 13.4 Mean= 28.1 ± 14.4 70 138 223 118 986 144 97 Great Britain Australia California Michigan, USA Great Britain Great Britain New Zealand Churcher and Lawton 1987 Barratt 1997 Crooks and Soulé 1999 Lepczyk et al. 2003 Woods et al. 2003 Baker et al. 2005 Van Heezik et al. 2010
What do pet cats kill? (Mitchell and Beck 1992, Barratt 1998, Crooks and Soulé 1999, Woods et al. 2003, Kays and DeWan 2004, Baker et al. 2008, van Heezik et al. 2010)
How many cats kill how much wildlife? How many free-roaming pet cats hunt and how often? Do demographic factors, season, roaming habitat or time spent outdoors influence hunting behaviors? What is the most common type of suburban cat prey?
The Kittycam Approach Animal-borne video cameras Allow direct observation of behavior 1998-present Whales, sharks, seals, turtles, grizzlies, lions Food selection, habitat use, species interactions, social behaviors CritterCams KittyCams
KittyCam methods Site: Athens-Clarke County, Georgia High densities of free-roaming cats, valuable habitat to native wildlife 60 owned free-roaming cats sample from a population of ~13,500
KittyCam methods Design: 12-15 cats per season (Nov. 2010-Oct. 2011) Owners place KittyCams on their free-roaming cats 7-10 days of video/cat (daily hrs outside vary, avg of 38 hrs/cat) Volunteer incentive: Free health screening
KittyCam methods Equipment: Lightweight Mounted on break-away collar VHF transmitter Motion sensor LED lights Video data stored onto a microsd card
KittyCam methods Events recorded per day per cat Prey identified, grouped by class Total recorded hours, weather and habitat details recorded 55 cats videos analyzed nestling Cat-eye views housemate
KittyCam predation results Descriptive Results : 30 M, 25 F, all sterilized age 0.5-19.5 years (mean= 5.8) 8 rural habitat, 47 in suburban neighborhoods 44% (24 cats) witnessed stalking, chasing 30% (16 cats) successfully captured prey 2.4 predation events/successfully hunting cat during 1 wk roaming cats Frequency of predation events in one week of footage (n=16)
KittyCam predation results prey Frequency of Prey types, n=39 total prey from hunting cats Cool = Dec-Feb, Warm= Mar-Nov Only 1 of the 31 vertebrates was non-native
KittyCam predation results Proportion of cat prey (n=39)
KittyCam video
KittyCam video
KittyCams: Some Pet Cats Kill Wildlife What influences hunting behavior? Cats roaming during warm season were ~6x more likely to exhibit hunting behavior Cat age, sex, roaming habitat (rural/suburban) did NOT influence hunting behavior Prey counts: Previous studies underestimate prey -cats leave or consume most items Prey type: Previous studies missed reptiles? Mammals constitute ~60% of cat prey in previous studies, birds ~23%, reptiles, amphibians < 5% (Baker et al 2008, Barratt 1998, Crooks and Soule 1999, van Heezik et al 2009, Woods et al 2003)
KittyCam images
Cats are spending their nights looking for animals to murder. Huffington Post, 8 Aug 2012
Loss et al 2013 Nature Communications Model predicts: 1.4-3.7 Billion birds every year in the US 6.9-20.7 Billion mammals 69% of kills attributed to ferals, 31% to pet cats Far exceeds previous estimates (Dauphine et al 2009, Coleman and Temple 1997)
Loss et al 2013 Nature Communications Previously, impact of cats deemed negligible compared to habitat loss, window collisions etc. but without knowing which species are killed (rare, native, etc) hard to assess the importance of threat! ** no good estimate of stray cats **used stray cat predation rates from 2 papers rural barncats sensitivity analysis: main cause of variation in estimates
A Similar study from Canada Blancher, 2013 Avian Conservation and Ecology Cat predation of birds is one of the largest human related sources of mortality there 100-300 million birds annually in Canada, also mostly due to stray cats 59% of kills, average of 7 birds a year for pets but an average of 70/year for feral cats studies with info on stray cat predation use scat analysis to quantify (2 problems:) scavenging, doesn t detect captures not consumed
While it is hard to quantify wildlife take by feral cats, we can be certain there is cause for conservation concern, especially on island habitats Other direct effects- captures that injure wildlife but don t immediately kill Wildlife rehabilitators trying to quantify this now
Indirect effects of cats on wildlife Bonnington et al 2013 Journal of Applied Ecology Sublethal effects on birds just the sight of cats near nests causes blackbirds to feed their chicks less often slower growth rate, less healthy, up to 40% lower growth alarm calls/noises of blackbirds defending their nests ends up attracting other predators
Next, use kittycams Repeat in different geographic locations Study percent hunters, frequency of hunting and predation rate of STRAY cats Study wildlife populations (species) to determine if mortality due to cats is additive or compensatory cats responsible for 47% of mortality of small sample post fledgling gray catbirds in DC (Balogh et al 2011) urban birds in New Zealand are negatively affected by this mortality source (van Heezik et al 2010)
In the meantime Recommendations for cat owners www.kittycams.uga.edu Results summaries, image and video examples Links to other online resources
Existing educational efforts
Keeping roaming cats and wildlife safe CatBib reduces captures, does not affect other behaviors (Calver et al 2007) Pet supervision
Project Acknowledgements We thank the following project supporters: National Geographic, Oconee Rivers Audubon Society, The Morris Animal Foundation, The Pender Pet Caring Foundation and The Kenneth C. Scott Charitable Trust We also acknowledge the following Warnell and Veterinary students for their assistance with health screens or video analysis: Shaun Boone DVM, Kristy Segal, Albert Mercurio, Barbara Shock, Maren Mason, Brendon Meany, Mandy Smith, Nevena Martin, Brittany Buckley, LeeAnne Lefavi, Anna Schmidt, Shay Fain, Viviana Gonzalez Thank you to Morgan Nolan for her assistance with our website.
Questions? Manuscripts about KittyCams research: Loyd, K.T., S.M. Hernandez, J.P. Carroll, G.J. Marshall, and K. J. Abernathy. 2013. Quantifying free-roaming domestic cat predation using animal-borne cameras. Biological Conservation 160: 183-189. Loyd, K.T., S.M. Hernandez, B.C. Shock, G.J. Marshall, and K.J. Abernathy. In Press. Risk factors experienced by free-roaming cats in a suburban, southeastern town. Veterinary Record. k.loyd@asu.edu