"Reducing the rate of predation on wildlife by pet cats: The efficacy and practicability of collar-mounted pounce protectors"
BIOLOGICAL CONSERVATION, Vol 137, Issue 3, July 2007, pp 341-348
Michael Calvera, Sandra Thomasa, Stuart Bradleya, and Helen McCutcheonb a-School of Biological Sciences and Biotechnology, Murdoch University, Murdoch, Western Australia, Australia b-School of Veterinary Studies, Murdoch University, Murdoch, Western Australia, Australia
In an attempt to provide sound advice to owners seeking to curb the predatory behaviour of their pet cats, we evaluated whether or not the commercial collar-worn product the CatBib reduces the number of vertebrates caught by pet cats. We also tested whether the colour of the CatBib influenced its effectiveness, or if supplementing the CatBib with a bell could reduce predation further. Fifty-six cats identified by their owners as known hunters completed the study, which took place in Perth, Western Australia over a six-week period in November/December 2005 (southern hemisphere late spring/early summer). Each cat spent a period of three weeks wearing a CatBib and three weeks without it and the number of prey brought home during each period was recorded. Participating cats caught a total of 13 bird species, five mammal species, and 11 herp (reptile and frog) species. The mammal the Southern Brown Bandicoot was the only prey species of conservation concern.
CatBibs stopped 81% of cats from catching birds, 45% of cats from catching mammals, and 33% of cats from catching herptofauna.
CatBibs of both colours were equally effective at reducing predation. There was no statistically significant evidence that adding bells conferred additional protection. Most cats (86%) adjusted almost immediately to wearing a CatBib, 10% took a day or so and only 4% took longer
- The CatBib is especially effective in reducing predation on birds. Predation on mammals is also reduced, but not to the same extent. There may be limited protection for herps.
- There was no statistically significant evidence that differently coloured CatBibs varied in their effectiveness.
- There was no statistically significant evidence that cats wearing a bell as well as a CatBib caught fewer prey than cats wearing a CatBib alone.
- Most cats (86%) adapted almost immediately to the CatBib, 10% took a day or so and only 4% took longer.
- Direct comparisons of the relative effectiveness of CatBibs, bells and electronic warning devices must be made cautiously because no researcher has tested them all simultaneously. However, the reductions in total numbers of prey caught by cats wearing CatBibs or CatBibs and bells in this study are similar to or better than those reported for the other devices in the UK by Ruxton et al. (2002) and Nelson et al. (2005). The 72% reduction in the numbers of birds caught by cats fitted with a CatBib compares favourably to the figures of 34% for bells alone and 51% for electronic warning devices alone (Nelson et al. 2005). The 45% reduction in the numbers of mammals caught by cats fitted with a CatBib or a CatBib and a bell is similar to the figures of 34% for bells alone and 38% for electronic warning devices alone (Nelson et al. 2005).
- While the sample size was small, only two of the 11 cats injured in fights were wearing CatBibs. Possibly the CatBibs make a cat look larger and more formidable, discouraging aggression. Alternatively, cats wearing them may be less inclined to pick a fight.
- Overall, the CatBib is a safe and effective means of reducing predation by pet cats, especially when birds are the prey. Cat owners can use the product with confidence.
Cat ownership is declining in Australia in contrast to the increased popularity of pet cats in Europe and the United States (REARK 1994, Perry 1999, Chaseling 2001, McGreevy et al. 2002). One significant reason may be a widely held view in Australia that pet cats are bad for wildlife either by roaming and hunting in remnant bushland or by excluding wildlife from domestic gardens (Baldock et al. 2003, Grayson et al. 2002, Grayson and Calver 2004, Lilith et al. in press). Reducing the incidence of predation by pet cats would benefit wildlife conservation and enhance the image of pet cats.
Several collar-worn devices are marketed to reduce predation by pet cats. Recent detailed studies of their effectiveness suggest that bells reduce prey captures by 34 - 48% (Ruxton et al. 2002, Nelson et al. 2005) and that electronic warning devices achieve a 38 - 51% reduction (Nelson et al. 2005). However, one device not yet tested is the CatBib, a lightweight neoprene bib worn on a collar. It functions both as a visual warning to prey and a barrier to paws when pouncing, reducing hunting success. This study assessed the effectiveness of the CatBib, a product marketed by Cat Goods Inc. (Oregon, USA) in reducing predation of birds by pet cats in an Australian context.
The study took place in Perth, Western Australia over a six-week period in November/December 2005 (southern hemisphere late spring/early summer). In October 2005, 63 volunteers were accepted from 82 respondents to advertisements in local newspapers seeking assistance from owners of cats which were active hunters. Respondents whose cats did not catch on average one prey every three weeks were declined. Most volunteers came from the outer suburban foothills where cats have ready access to native bushland. All cats were neutered and there were almost equal numbers of males and females.
The CatBib is made of neoprene, a light, strong and tear resistant synthetic fabric used in wetsuits. It attaches to a collar via hook and loop pads (velcro), which can release if the CatBib snags. Although there is only one size, varying the point of attachment of the CatBib allows some size adjustment for large or small cats. Bibs are available in five colours, two of which were tested in this study. The retail price is $8.95 (US), without a collar. While cats can carry out all activities while wearing a CatBib, the manufacturer suggests that bibs are only worn when the cat is outside. During this study owners were asked to ensure that their cats always wore bibs when outside during treatment weeks.
Male and female cats were allocated randomly to four treatments: teal CatBib only, teal CatBib plus a bell, purrple CatBib only and purrple CatBib plus a bell. Half the cats in each treatment were fitted with the device for three weeks followed by three weeks without the device, while the others were monitored for three weeks without the device followed by three weeks with it. This design ensured that all cats spent a period with and without the device as well as controlling for possible effects of the sequence of treatments or changes in prey availability over time. All collars and CatBibs were fitted initially during a home visit. If the cat was not already wearing a collar, it was given at least one week to adjust to the collar before the CatBib was fitted. Only safety collars were used.
Owners collected the bodies of any dead prey brought home by their cats and reported instances where live prey were rescued and released. All cases where the prey was dead or was released only after intervention by the owner were recorded as captures. If the owner saw a cat with a prey animal but it escaped without the owner's intervention, no capture was recorded. Prey bodies were identified to species. Most prey released after owner intervention were classed simply as mammals, birds or herps (reptiles and frogs) unless the owner provided a clear description identifying the species conclusively.
The results below are summaries of detailed statistical analyses of the data.
Characteristics of cats and cat husbandry
The 63 cats accepted had a mean age of 5 years (females) and 4.5 years (males). Most were not pure breeds, but there were some pure breed Russian Blues and Burmese, one pure breed Persian and one pure breed Abyssinian. 13% lived entirely outdoors, while the others were allowed indoors at least some of the time. Only six cats were occasionally restricted indoors. Fighting was common, with two cats wearing bibs and nine cats not wearing bibs suffering fight-related injuries (scratches, bites, abscesses) over the six-week trial. Four cats, none of which was wearing a bib, disappeared from their homes for at least two days at some point during the trial.
Most cats (86%) adjusted almost immediately to wearing a CatBib, 10% took a day or so and only 4% took longer. Seven cats lost their CatBib at least once during the trial and one lost its CatBib six times.
Prey capture and effectiveness of treatments
Over the six weeks of the trial the participating cats caught 13 bird species (11 native), 11 herp (reptile and frog) species (all native) and five mammal species (two native). The mammal the Southern Brown Bandicoot was the only species of conservation concern (Lower Risk, Near Threatened: Maxwell et al. 1996). On average, each cat caught 2.93 mammals, 1.11 birds and 1.20 herps. Male and female cats caught similar numbers of prey.
Alone or in conjunction with a bell CatBibs stopped 81% of cats from catching birds and 45% of cats from catching mammals. The effects for birds and mammals are strong, but the effect for herps is weak. CatBibs of both colours were probably equally effective at reducing predation. Bells are unlikely to cut predation beyond the reductions already caused by CatBibs.
We are grateful to the many owners who kindly volunteered their cats for the study. Cat Goods Inc. supplied the CatBibs, Mr Ray Dunn of Symonds donated the safety collars and bells and Dr Karen Johnstone of Hills Pet Nutrition provided sample bags of cat food to reward the volunteer cats. Dr Ric How, Mr Ron Johnstone, Ms Claire Stevenson and Mr Brad Maryan of the Western Australian Museum identified the prey. Mr Ian Davis, Environmental Programs Manager for the City of Melville, and Mr John DeJose, manager of the Cat Haven in Perth, provided encouragement and advice. The City of Melville and the Murdoch University Research Excellence Grants Scheme provided financial support.
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