Effectiveness of the Birdsbesafe® anti-predation collar

Hall, C. M., Fontaine, J. B., Bryant, K. A., & Calver, M. C. (2015). Assessing the effectiveness of the Birdsbesafe® anti-predation collar cover in reducing predation on wildlife by pet cats in Western Australia. Applied Animal Behaviour Science.


Many pet cats hunt and, irrespective of whether or not this threatens wildlife populations, distressed owners may wish to curtail hunting while allowing their pets to roam. Therefore we evaluated the effectiveness of three patterned designs (simple descriptions being rainbow, red and yellow) of the anti-predation collar cover, the Birdsbesafe® (BBS), in reducing prey captures by 114 pet cats over 2 years in a suburban Australian context. The BBS offers a colourful indicator of a cat's presence and should therefore alert prey with good colour vision (birds and herpetofauna), but not most mammals with limited colour vision. We also interviewed the 82 owners of cats in the study about their experience using the BBS and their assessment of the behavioural responses of their cats.

In the first year of the study, which focused on the effectiveness of different BBS colours, captures of prey with good colour vision were reduced by 54% (95% CL 43% - 64%) when cats were wearing a BBS of any colour, with the rainbow and red BBS more effective than the yellow when birds were prey. Captures of mammals were not reduced significantly. The second year assessed the rainbow BBS alone, and those data combined with rainbow data in the first year found a significant reduction of 47% (95% CL 43% - 57%) in capture of prey with good colour vision, with no effect of differences across years. We found no evidence that cats maintained a lower predation rate once the BBS was removed. Seventy-nine per cent of owners reported that their cats had no problems with the BBS and another 17% reported that their cats adjusted within 2 days. Fourteen owners reported that their cats spent more time at home and ate more while wearing the BBS. Two owners reported their cats stayed away from home more while wearing it. Sixty-four per cent of owners using the red collar, 48% using rainbow and 46% using yellow believed that it worked. Overall, 77% of owners planned to continue using the BBS after the study had finished. The BBS is an option for owners wishing to reduce captures of birds and herpetofauna by free-ranging cats, especially where mammalian prey are introduced pests. To date, the BBS is the only predation deterrent that reduces significantly the number of herpetofauna brought home. It is unsuitable where endangered mammalian prey or large invertebrates are vulnerable to predation by pet cats.

Belling the cat

After reviewing the available articles considering the effect of bells on feline hunting behaviour, we found a big difference between results of surveys considering cats wearing bells previously to the study and studies where cats were experimentally provided with bells.

Surveys show that bells have little effect on predatory behaviour. After one study, 33% of pet cats wore a bell in UK. Cats wearing a bell hunted fewer mammals than un-belled ones, but there was no difference for birds and herps; probably birds rely more on visual cues than mammals, but maybe skilled cats wear bells more frequently than the rest (Woods et al. 2003). Paton (1991) relying on respondents' memory, found that belling cats has no incidence in the number of preys brought home. In Australia, Reark (1994) found that belled cats hunted more than un-belled ones, but there were not data on how much did they use to hunt before wearing a bell. Barrat (1998) did not find any difference between cats wearing bells or not. In New Zealand, Morgan et al. (2009) got similar results. Hansen (2010) also found no evidence of effect of bells on predation. Comparing sites where belling is compulsory and sites without obligation, no positive correlation was found between small mammal abundance and regulations (Lilith et al., 2010).

Experimental studies where cats were equipped with bells show a decrease between 30 and 50% in the number of preys (Ruxton et al., 2002; Nelson et al., 2005; Gordon et al., 2010). Nevertheless, those studies were, probably, too short (4-8 weeks) to allow cats to learn how to silently stalk their prey. Electronic devices tend to be more effective than bells anone, but are no exempt of problems (Clark & Burton, 1998; Clark, 1999; Nelson et al., 2005). Other devices were more effective, reducing up to 80% the number of preys, but the period was also short (3 weeks) (Calver et al., 2007).

Bright coloured collars seem to be very effective to warn birds on the approaching cat: collared cats kill as much as 19 times less than uncollared animals (Willson et al., 2015), and this could be independent of the cat's skills.

There is a need of longer term studies to better understand the whether

- the effect observed in experimental studies is due to the lack of training, and cats wearing a bell for a longer time will improve their chances

- the lack of effect in surveys is due to a potential bias towards skilled cats wearing bells more frequently that less capable ones.

Novel cat collar to reduce avian mortality

Willson, S. K., Okunlola, I. A., & Novak, J. A. (2015). Birds be safe: Can a novel cat collar reduce avian mortality by domestic cats (Felis catus)?. Global Ecology and Conservation.

The domestic cat (Felis catus) has been described as the largest anthropogenic threat to songbird populations in North America. We examined the effectiveness of a novel cat collar in reducing avian and small mammal mortality by cats. The 2-inch wide Birdsbesafe® collar cover (CC) is worn over a nylon quick-release collar, and the bright colors and patterns of the CC are hypothesized to warn birds of approaching cats. We conducted two seasonal trials, each lasting 12 weeks, in autumn 2013 (n=54 cats) and spring 2014 (n=19 cats). Cats were randomly assigned to two groups, and CCs with interior collars were removed or put on every two weeks, to control for weather fluctuations and seasonal change. Cats wearing Birdsbesafe® CCs killed 19 times fewer birds than uncollared cats in the spring trial, and 3.4 times fewer birds in the fall. Birdsbesafe® CCs were extremely effective at reducing predation on birds. Small mammal data were less clear, but did decrease predation by half in the fall. The Birdsbesafe® CC is a highly effective device for decreasing bird predation, especially in the spring season. We suggest that the CCs be used as a conservation tool for owned as well as feral cats.

Alien mammal eradication and quarantine on inhabited islands in the Seychelles

Mertori, D., Climo, G., Laboudallon, V., Robert, S., & Mander, C. (2002). Alien mammal eradication and quarantine on inhabited islands in the Seychelles. In Veitch, C. R., & Clout, M. N. (2002). Turning the Tide: The Eradication of Invasive Species: Proceedings of the International Conference on Eradication of Island Invasives,[University of Auckland, 19 to 23 February 2001] (No. 27). IUCN, 182-198.

During the period 1996-2000, eradication of five introduced mammal species (feral cat (Felis catus), rabbit (Oryctolagus cuniculus), ship rat (Rattus rattus), Norway rat (R. norvegicus) and house mouse (Mus domesticus)), was attempted on four inhabited islands, including three resort islands, ranging in size from 101–286 ha in the Seychelles group, Indian Ocean. Objectives were to avert extinctions of, and restore urgently-needed habitat for, localised threatened endemic animals and to facilitate ecological restoration in line with a national biodiversity strategy. Local political, economic and biological constraints meant that adaptations were necessary to traditional poisoning and trapping methods and regimes. Furthermore, since no rat-free island was available to which native animals at risk from primary and/or secondary poisoning might be transferred, it was necessary to maintain approx. 590 individuals of three threatened animal species in captivity for the three months of the eradication programme. Strategies and techniques developed, and some of the many challenges encountered in conducting eradication and quarantine programmes on inhabited, tropical islands are outlined, together with progress to date. One island (Bird) has been maintained free of rats and rabbits since their eradication in 1996. Two others (Denis and Curieuse) are now free of feral cats but have been recolonised by Rattus rattus since eradication attempts in 2000. The fourth (Frégate), was successfully cleared of R. norvegicus and mice in 2000, in time to avert extinctions of localised threatened endemic animals. These positive results will, we hope, inspire similar effort on other inhabited islands with high biological values or potential.

Movements and predation activity of feral and domestic cats on Banks Peninsula.

Hansen, C. M. (2010). Movements and predation activity of feral and domestic cats (Felis catus) on Banks Peninsula. MSc Thesis, Lincoln University.

Domestic house cats (Felis catus) are seen as a potentially damaging predator to numerous threatened prey species, especially those with access to natural environments that contain abundant native species. However, the role of domestic cats as major predators is controversial and the degree to which they negatively impact bird populations is debated. Natural areas, such as Orton Bradley Park in Charteris Bay on Banks Peninsula, are home to many native and endemic bird species, including the threatened kereru (Hemiphaga novaeseelandiae). Charteris Bay is an urban to rural (including natural areas) gradient, and provides an ideal study site characteristic of much of New Zealand. Charteris Bay cat owners were enlisted to obtain data on their cats’ physical characteristics, management and lifestyle and how this may be influencing hunting activity. Age was the only significant influencing factor on how often a cat was reported to hunt, younger cats hunted more often than their older counterparts. Sex, size, breed, type of food fed, frequency of feeding, restricting cat indoors, use of collars and bells, distance seen from the home-site had no significant impact on hunting activity. Cat owners were then enlisted to participate in a prey recording survey of the prey that their cats brought home. Mean prey items per cat was 15.6 (± 4.5 S.E.). The number of prey caught by each cat ranged from 0 to 79 items over six months. Rodents were the prey item retrieved most often (48% of the total prey take) and Lagomorphs were the next most commonly retrieved prey item (38%). Birds, lizards and invertebrates made up the remaining 14% of prey items retrieved. Of the total prey retrieved 2.4% were native species. A sample of eight domestic cats participated in satellite tracking using GPS technology to investigate home ranges and movements. Home range sizes ranged from 0.7 to 13.4 ha (100% MCP). Maximum straight line distances travelled from the home site ranged from 80 to 301m. Nocturnal home range sizes were significantly larger than diurnal ranges. One feral cat trapped and tracked at Orton Bradley Park had a home range size of 415 ha (100% MCP). Digital camera traps were set up at 31 sites around the park, density estimates of 1.2 - 1.6 cats/ km² for feral cats were calculated using photographic recapture data from the camera traps. Domestic house cats in this study appeared to have little impact on native species populations of birds, lizards or invertebrate populations. These cats may provide a net benefit to these populations through removal and suppression of other pests and predators. Proximity to Orton Bradley Park was not a significant influencing factor for the movement or hunting behaviour for the cats in this study. Feral cats at Orton Bradley Park exist at low densities and, like their domestic counterparts, probably suppress pests and predators. A successful pest management plan at Orton Bradley Park would require removal of all levels of pests (i.e. cats, possums and rodents) and the prevention of immigration back into the site.




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Bells and bibs reducing predation by cats in Australia

Calver, M., Thomas, S., Bradley, S., & McCutcheon, H. (2007). Reducing the rate of predation on wildlife by pet cats: The efficacy and practicability of collar-mounted pounce protectors. Biological Conservation, 137(3), 341-348.

We evaluated whether a collar-worn pounce protector, the CatBib™, reduces the number of vertebrates caught by pet cats and whether its effectiveness was influenced by colour or adding a bell. Fifty-six cats identified as hunters were studied in Perth, Australia over six weeks in November/December 2005 (southern hemisphere spring/summer). Cats spent three weeks wearing a device and three weeks without it and we recorded the number of prey brought home during each period.

Cats caught 65 birds (13 species), 67 herpetofauna (11 species) and 164 mammals (five species). Alone or together with bells CatBibs stopped 81% of cats from catching birds, 33% from catching herpetofauna and 45% from catching mammals. Cats wearing CatBibs or CatBibs and bells caught only 25% of all birds, 43% of all herpetofauna and 36% of all mammals captured. Both colours were equally effective. Adding bells conferred no additional protection. Only one cat did not adjust to the CatBib and there was no long-term evidence that CatBibs altered cats’ fighting or wandering behaviour.

Owners volunteered because of one or more of: environmental concern (81%), curiosity (38%), personal (35%) or family (24%) distress caused by hunting. Most owners (70%) said they would continue to use CatBibs although only 17% were doing so eight months later because some cats had stopped hunting or lost their CatBibs. Although confinement of pet cats is the complete solution to preventing predation on wildlife, deterrents such as the CatBib are effective if used consistently.

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Bells and electronic sonic device reducing predation by cats in UK

Nelson, S. H., Evans, A. D., & Bradbury, R. B. (2005). The efficacy of collar-mounted devices in reducing the rate of predation of wildlife by domestic cats. Applied Animal Behaviour Science, 94(3), 273-285.

Volunteer cat owners from across the UK were recruited to take part in two trials designed to test the efficacy of collar-mounted warning devices in reducing cat predation rates of native wildlife. Cats equipped with a bell returned 34% fewer mammals and 41% fewer birds than those with a plain collar. Those equipped with an electronic sonic device returned 38% fewer mammals and 51% fewer birds compared with cats wearing a plain collar. There was no significant difference in prey return rates by cats wearing collars equipped with one bell, two bells or the sonic device. Warning devices mounted on quick-release collars are recommended as an effective way of reducing wildlife kill rates by domestic cats. Future research and development aimed at further improving the efficacy of sonic devices is recommended.

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You can see early reports of CatAlert device here

Clark, N. A. & N.H.K. Burton (1998). A pilot field trial into the effectiveness of the CatAlert™ collar at reducing predation by domestic cats. British Trust for Ornithology.

Clark, N. A. (1999). Progress report on the effectiveness of the Mark II CatAlert™ collar at reducing predation by domestic cats. British Trust for Ornithology.

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Bells reduce predation by cats in NZ

Gordon, J. K., Matthaei, C., & Van Heezik, Y. (2010). Belled collars reduce catch of domestic cats in New Zealand by half. Wildlife Research, 37(5), 372-378.

Context. As evidence accumulates implicating domestic cats as significant predators of urban wildlife, the need for effective mitigation of potentially negative impacts becomes more pressing. Belled collars are probably one of the cheapest and least intrusive methods, although the opinion of a proportion of members of the public in New Zealand is that they are not effective.

Aims. We aimed to determine whether belled collars reduced prey catch.

Methods. Prey caught and brought back home by cats that were regular hunters during 6 weeks when they wore a belled collar was compared with prey caught during 6 weeks when they did not wear a collar.

Key results. Predation of birds and rodents was reduced by 50% and 61%, respectively. The number of rats, lizards and insects was not significantly reduced; however, these constituted a small proportion of the total catch. Sex and age of cats, as well as time did not affect catch rates, with the exception that older cats were more likely to catch rats (Rattus spp.) than were younger cats. Most of the cats in the study were young, reflecting our selection criteria that cats be regular and frequent hunters.

Conclusions. The degree to which catch of birds and rodents was reduced is similar to that reported in two experimental studies in the UK, and confirms that belled collars are effective in the New Zealand environment.

Implications. In New Zealand, small mammals are introduced pests and hunters of native wildlife; predation by cats may regulate their populations in urban areas and so care should be taken when instituting cat-control measures. It is also possible that a 50% reduction in predation may be insufficient to ensure viability for some urban wildlife populations.

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Predation by house cat in Canberra

Barratt, D. G. (1997). Predation by house cats, Felis catus (L.), in Canberra, Australia. I. Prey composition and preference. Wildlife Research, 24(3), 263-277.

This paper attempts to apply theory from more than 100 years of scientific experience and experimentation in predator-prey ecology and introduced species ecology to predict the likely effects of predation by domestic cats (Felis catus) on prey populations and community structure. Those aspects of the predatory behaviour of domestic cats which are of most importance in predicting their impact on prey populations: I) the degree of prey selectivity or 'dietary preference'; 2) the exhibition of switching behaviour; 3) changes in predatory activity in response to changes in prey density; and 4) the extent to which high and constant densities of the predator are ameliorated by reduced prey consumption rates as a result of dietary supplement.

In suburban environments, the influence of predation by domestic cats on prey abundance and community structure probably increases, relative to the influence of habitat change, with increasing suburb age, particularly in the absence of physical disturbances such as fire. However, it may never be as important as habitat availability and indeed may never be significant at all. Removal of the predator may allow some animal species to increase in abundance but others may decline. The details of these changes are very difficult to predict. Similarly, following predator removal, total species diversity is as likely to decline due to increased inter-specific competition, as it is to increase due to the invasion of species previously excluded by predation.

In remnant habitat, the impact of predation by domestic cats is probably less likely to be important in determining the relative abundance of the more common species than in suburban environments, but more likely to contribute to local extinctions of rare species. As in suburban environments, predation on introduced species in remnant habitat may reduce predation on native species. However, the ability of domestic cats to control introduced species which prey on, or compete with, native species will be difficult to demonstrate. In light of this uncertainty, any attempt to prevent domestic cats hunting in remnant habitat patches should be integrated with a program to eliminate or control populations of other introduced species, such as black rats and rabbits, which are preyed upon by domestic cats and are known to prey on or compete with native species

Barratt, D. G. (1998). Predation by house cats, Felis catus (L.), in Canberra, Australia. II. Factors affecting the amount of prey caught and estimates of the impact on wildlife. Wildlife Research, 25(5), 475-487.

Information on the amount of vertebrate prey caught by house cats in Canberra was collected by recording prey deposited at cat owners’ residences over 12 months. The amount of prey taken was not significantly influenced by cat gender, age when neutered, or cat breed. Nor did belling or the number of meals provided per day have a significant influence on the amount of prey caught. The age of the cat and the proportion of nights spent outside explained approximately 11% of the variation in the amount of prey caught by individual cats. In all, 43% of variation in predation on introduced species (predominantly rodents) was explained by distance from potential prey source areas (i.e. rural/grassland habitat) and cat density. The mean number of prey reported per cat over 12 months (10.2) was significantly lower than mean predation per cat per year based on estimates made by cat owners before the prey survey began (23.3). Counts of the amount of prey caught by house cats were highly positively skewed. In all, 70% of cats were observed to catch less than 10 prey over 12 months, but for 6% of cats, more than 50 prey were recorded. Estimates of predation by house cats, particularly extrapolated estimates, should be treated with caution. The total number of prey caught by house cats in Canberra estimated using the sample median was approximately half the estimate based on the sample mean. Predation estimates alone do not prove that prey populations are detrimentally affected, especially in highly disturbed and modified environments such as suburbs. Impacts on native fauna are likely to be most significant in undisturbed habitat adjacent to new residential developments.



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Bells reduce by half predation by cats

Ruxton, G. D., Thomas, S., & Wright, J. W. (2002). Bells reduce predation of wildlife by domestic cats (Felis catus). Journal of Zoology, 256(1), 81-83.

Twenty-one cat owners from a 100 km²  area, centred on Carnforth, Lancashire, England, recorded each dead prey item delivered by their cat or cats during an 8-week period, following one of three experimental schedules, each of which required each cat to have a bell on a collar for only half of the time. The mean number of items each cat delivered to the owner was 2.9 in the 4 weeks when the cats had a bell attached, compared to 5.5 for the equivalent time when the bell was absent. The bell had no effect on the relative numbers of different prey types delivered, and there was no evidence that the cats adapted their hunting behaviour to reduce the effect of the bell over time.


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Apparent lack of influence of cat regulations on small size mammals abundance in urban bushland

Lilith, M., Calver, M., & Garkaklis, M. (2010). Do cat restrictions lead to increased species diversity or abundance of small and medium-sized mammals in remnant urban bushland?. Pacific Conservation Biology, 16(3), 162.

We took advantage of cat regulations enacted within differing subdivisions in the City of Armadale, Western Australia, to test the hypotheses that the species diversity (measured by the Shannon-Weiner index) and abundance of small and medium-sized mammals should be higher in native bushland within or adjacent to subdivisions where cats are restricted compared to similar areas where cats are not restricted. There were three different regimes of cat regulation: no-cat zone (strict prohibition of cat ownership applying in one site), compulsory belling of cats and night curfew at one site, and unregulated zones (free-roaming cats applying at two sites). Both sets of cat regulations were in place for approximately 10 years prior to our survey. We also measured structural and floristic features of the vegetation at each site that might influence the species diversity and abundance of small and medium-sized mammals independently or interactively with cat activity.

No significant differences in species diversity were found across the sites and KTBA (known-to-be-alive) statistics for Brushtail Possums Trichosurus vulpecula and Southern Brown Bandicoots Isoodon obesulus, the two most abundant medium-sized mammals present, were similar across all sites. The smaller Mardo Antechinus flavipes, which could be regarded as the most susceptible to cat predation of all the native species trapped because of its size, was trapped mostly at an unregulated cat site. Total mammals trapped at the unregulated cat sites exceeded those caught at the two sites with restrictions, but these unregulated sites also had significantly denser vegetation and there was a borderline (p = 0.05) rank correlation between vegetation density and mammal captures across all sites. It appears that pet cats are not the major influence on the species diversity or abundance of small and medium-sized mammals at these sites and that vegetation characteristics may be more important.

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Cats around a wetland

Morgan, S. A., Hansen, C. M., Ross, J. G., Hickling, G. J., Ogilvie, S. C., & Paterson, A. M. (2009). Urban cat (Felis catus) movement and predation activity associated with a wetland reserve in New Zealand. Wildlife Research,36(7), 574-580.

Context. House cats are increasingly suggested as having major ecological impacts in semiurban environments. Information on the activity of house cats is relatively scarce, especially in habitats such as wetlands.

Aims. This study examines the movement and foraging behaviour of house cats living on the periphery of a wetland reserve in Christchurch city, New Zealand.

Methods. Twenty-one domestic cats living in a suburban residential area were studied using radiotelemetry to determine home-range size, mean and maximum distances travelled into the adjacent wetland, and the proportion of time spent in the wetland over a 12-month period. Surveys of prey retrieval for 88 cats were also carried out by cat owners over the same 12-month period.

Key results. Cat age and the distance of the cat’s home from the periphery of the wetland were highly correlated with cat movement and hunting activity. These movements were not markedly influenced by season or time of day. Younger cats (<6 years of age) living on the periphery of the wetland had larger home-range sizes, moved significantly further into the wetland and spent a significantly greater proportion of time in the wetland. Cats living close to the wetland also brought a greater diversity and a greater total number of prey items to their home-site. Rates of predation were not significantly influenced by sex or whether the cat was wearing a bell. The most common prey items were introduced rodents and birds; however, 172 of 981 prey items were identified as a native common skink.

Conclusions.Consequently, cats living in households on the wetland periphery currently pose a predation risk for the wetland species, and the impact of cats on the native skink population warrants further investigation.

Implications. This study suggests that domestic cats will exploit wild habitats but that their potential impact will have both positive (predation of introduced pest species) and negative (occasional direct predation) effects on native wildlife.


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Cats killing billions of animals in the US

By Rebecca Morelle
Science reporter, BBC World Service 29 January 2013 

Cats are one of the top threats to US wildlife, killing billions of animals each year, a study suggests. The authors estimate they are responsible for the deaths of between 1.4 and 3.7 billion birds and 6.9-20.7 billion mammals annually.

Writing in Nature Communications, the scientists said stray and feral cats were the worst offenders. However, they added that pet cats also played a role and that owners should do more to reduce their impact.

The authors concluded that more animals are dying at the claws of cats in the United States than in road accidents, collisions with buildings or poisonings. The domestic cat's killer instinct of has been well documented on many islands around the world. Felines accompanying their human companions have gone on to decimate local wildlife, and they have been blamed for the global extinction of 33 species. But their impact on mainland areas has been harder to chart.

To find out more, researchers from the Smithsonian Conservation Biology Institute (SCBI) and the US Fish and Wildlife Service carried out a review of studies that had previously looked at the predatory prowess of cats. Their analysis revealed that the cat killings were much higher than previous studies had suggested: they found that they had killed more than four times as many birds as has been previously estimated.

Birds native to the US, such as the American Robin, were most at risk, and mice, shrews, voles, squirrels and rabbits were the mammals most likely to be killed.

Dr Pete Marra from the SCBI said: "Our study suggests that they are the top threat to US wildlife."

The team said that "un-owned" cats, which they classified as strays, feral cats and farm cats, were killing about three times as many animals as pet cats, but that their owners could do more to limit the impact.

Dr Marra said: "We hope that the large amount of wildlife mortality indicated by our research convinces some cat owners to keep their cats indoors and that it alerts policymakers, wildlife managers and scientists to the large magnitude of wildlife mortality caused by cat predation."

A spokeswoman for the UK's animal welfare charity the RSPCA said that a properly fitted collar and bell could reduce a cat's success when hunting by at least a third.

http://www.bbc.co.uk/news/science-environment-21236690


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Loss of wildlife to domestic cats

Paton, D. (1991). Loss of wildlife to domestic cats. In Potter, C. (ed), The Impact of Cats on Native Wildlife: Proceedings of a Workshop held on May 8-9 1991. ANPWS, Canberra

Questionnaires asked people how many animals they thought their cat(s) had killed in the previous 12 months. Of the 3000 questionnaires distributed, 709 were returned, covering 700 cats in Adelaide suburbs, in country towns and in rural areas. The majority of the questionnaires (88%) came from members of birders' associations.

• Cats in rural areas were reported to catch over twice as many prey as suburban cats. 
• The average number of prey reported caught per year was 30. 
• Suburban cats (the majority of cats) were reported to catch less, and rural cats (far fewer in number) caught more. 
• Bells were ineffective 
• Most preys were non native

Survey on metropolitan domestic cats

Millwood, J. & T. Heaton 1994. The Metropolitan Domestic Cat. Petcare Information and Advisory Service, Melbourne. UAM Conference Proceedings - Canberra 1994

BACKGROUND 

In Australia in recent years, concern has been raised about the possible impact of cats, both domestic and feral, on native fauna populations. 

Concern about the role of domestics cats in particular has led some groups to consider cat management options. 

Management decisions are hampered, however, by a scarcity of scientific information on the interaction of domestic cats with native fauna.

Previous research has shown that domestic cats are catching native wildlife. But - how many? To date, none of the studies published have used sample groups which reflect domestic cat distribution, making it very difficult to draw conclusions about the behaviour of the cat population as a whole. 

Most people live in highly urbanised areas. It was suspected that a survey conducted over the full range of 

metropolitan populations would show that domestic cats in fact catch very few native fauna. 

Petcare Information and Advisory Service (PIAS) thus commissioned Reark Research Pty Ltd, an independent market research organisation, to conduct a detailed survey of the metropolitan cat in all Australian capital cities (except Darwin). The sample group was selected to represent domestic cat distribution within each city, thus ensuring that conclusions could be drawn about the metropolitan cat population. 

The survey was to provide information on the hunting behaviour of domestic cats and determine the size, age and neuter status of the metropolitan cat population. 

OBJECTIVES 

1. To clarify the hunting behaviour of the metropolitan domestic cat, including: 

• What creatures are caught; 
• How many creatures are caught; 
• How many native creatures are caught. 

2. To provide detailed information on the metropolitan cat population, including: 

• what percentage are desexed; 
• changes in cat population over the last 12 months

3. To provide information on factors likely to effect cat hunting behaviour, including: 

• confinement of cats by the owner to the property at night; 
• tendency of cats to roam from the owner's property; 
• wearing bells. 

SURVEY METHODOLOGY 

The survey was designed to provide complete coverage of the cat population within metropolitan Australia, covering the entire Statistical Division for each of the capital cities. 

The metropolitan region included within the scope of the survey covers 62.7 percent of the private dwellings 

throughout the whole of Australia. Within each city, sample selection was controlled to appropriately represent population distribution, and results were weighted accordingly. 

A systematic probability sample of telephone 'white page directory' listings within postcodes classified as 'relatively low' to 'high' population densities was generated. 

Over 4000 households were surveyed. The size of the sample group ensured that the maximum degree of error was limited to not more than + /-2 percent for all estimates relating to the total metropolitan domestic cat population. 

The questionnaire was sequenced to establish a rapport between interviewer and subject, and invite an open and non threatening discussion of the cat's behaviour, thus reducing possible bias due to recent media coverage of 'cat issues'. 

RESULTS 

1. Hunting Behaviour

The proportion of domestic cats which caught prey.

• 41 percent of cats caught introduced mammals such as mice, rats and rabbits (vermin), and 2 percent caught native mammals such as possums or bats. 
• 17 percent of cats caught reptiles or amphibians such as lizards, skunks, snakes or frogs. 
• 19 percent of cats caught introduced birds such as sparrows and starlings, and 7 percent caught native birds such as magpies or honey eaters. 

Overall, 56 percent of cats were reported to catch prey. (Note that as cats could catch more than one type of creature, the total number of cats catching prey is less than the sum of cats catching individual creatures) 

The number of prey caught by domestic cats

Over the period 12 months to April 1994, native species were 33% of metropolitan domestic cats caughts.

2. Domestic cat population

• Almost one million households (985 000), that is 25.2 percent of households throughout the capital cities of Australia own a cat. 
• The total number of cats living within those households is estimated as 1,397,000. 
• Fewer households own cats than a year ago, and the number of cats per cat owning household has also dropped. 
• In the past twelve months there has been a 10 percent decline in the metropolitan cat population. 

3. Factors likely to affect cat hunting behaviour

• 39 percent of the cat population was securely contained at night. 
• 79 percent of the cat population was reported to not roam away from the home surrounds during the day. 
• The proportion of cats which caught any creature was lower for those cats which were confined to the house at night, than those which were allowed out. 
• The proportion of cats which caught any creature was higher for those which wore bell collars than those which did not.

CONCLUSIONS 

The findings support the suspicion that metropolitan domestic cats are in fact catching substantially fewer native fauna than previously supposed. 

During the survey year, each domestic cat is estimated to have caught on average: 

• One fiftieth of a native mammal; 
• One fifth of a native bird; 
• One and a third native reptiles or amphibians; 
• Half of all creatures caught were vermin - mice, rats and rabbits. 

Contrary to common perceptions that cat numbers are increasing, it appears the metropolitan domestic cat population is in decline.

• The metropolitan domestic cat population decreased by 10 percent over April 1993-1994. 
• The vast majority (94 percent) of adult metropolitan domestic cats are desexed. 

Bell collars do not appear to be effective in preventing hunting, although conclusions are difficult to draw as owners are more likely to place bells on cats which are proven hunters. 

Those cats which spend most of their time around the home tend to hunt less.


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100 millions prey in five months in UK!!

Woods, M., R.A. McDonald & S. Harris. 2003. Predation of wildlife by domestic cats Felis catus in Great Britain. Mammal Review 33 (2), 174-188.

1. A questionnaire survey of the numbers of animals brought home by domestic cats Felis catus was conducted between 1 April and 31 August 1997. A total of 14 370 prey items were brought home by 986 cats living in 618 households. Mammals made up 69% of the items, birds 24%, amphibians 4%, reptiles 1%, fish <1%, invertebrates 1% and unidentified items 1%. A minimum of 44 species of wild bird, 20 species of wild mammal, four species of reptile and three species of amphibian were recorded.

2. Of a sample of 696 individual cats, 634 (91%) brought home at least one item and the back-transformed mean number of items brought home was 11.3 (95% CI 10.4–12.2). The back-transformed means and number of cats retrieving at least one item from each prey group were: 8.1 (7.4–8.9) mammals for 547 (79%) cats, 4.1 (3.8–4.5) birds for 506 (73%) cats, 2.6 (2.2–3.0) herpetofauna for 145 (21%) cats and 2.2 (1.8–2.7) other items for 98 (14%) cats. 

3. The number of birds and herpetofauna brought home per cat was significantly lower in households that provided food for birds. The number of bird species brought home was greater in households providing bird food. The number of birds and herpetofauna brought home per cat was negatively related to the age and condition of the cat. The number of mammals brought home per cat was significantly lower when cats were equipped with bells and when they were kept indoors at night. The number of herpetofauna brought home was significantly greater when cats were kept in at night.

4. Based on the proportion of cats bringing home at least one prey item and the backtransformed means, a British population of approximately 9 million cats was estimated to have brought home in the order of 92 (85–100) million prey items in the period of this survey, including 57 (52–63) million mammals, 27 (25–29) million birds and 5 (4–6) million reptiles and amphibians.

5. An experimental approach should be taken to investigate the factors found by this descriptive survey to influence the numbers of prey brought home by cats. In particular, investigation of potential management practices that could reduce the numbers of wild animals killed and brought home by cats will be useful for wildlife conservation, particularly in suburban areas.


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