Analyzing approaches to feral cat management

Stoskopf, M. K., & Nutter, F. B. (2004). Analyzing approaches to feral cat management-one size does not fit all. Journal of the American Veterinary Medical Association, 225(9), 1361-1964.
"... A varied array of tools needs to be available to facilitate humane solutions to a highly varied set of problems posed by the amazingly adaptable feral cat ..."

Citizen science as a tool for conservation

Cooper, C. B., Dickinson, J., Phillips, T., & Bonney, R. (2007). Citizen science as a tool for conservation in residential ecosystems. Ecology and Society,12(2), 11.

Human activities, such as mining, forestry, and agriculture, strongly influence processes in natural systems. Because conservation has focused on managing and protecting wildlands, research has focused on understanding the indirect influence of these human activities on wildlands. Although a conservation focus on wildlands is critically important, the concept of residential area as an ecosystem is relatively new, and little is known about the potential of such areas to contribute to the conservation of biodiversity. As urban sprawl increases, it becomes urgent to construct a method to research and improve the impacts of management strategies for residential landscapes. If the cumulative activities of individual property owners could help conserve biodiversity, then residential matrix management could become a critical piece of the conservation puzzle. “Citizen science” is a method of integrating public outreach and scientific data collection locally, regionally, and across large geographic scales. By involving citizen participants directly in monitoring and active management of residential lands, citizen science can generate powerful matrix management efforts, defying the “tyranny of small decisions” and leading to positive, cumulative, and measurable impacts on biodiversity.

Uses cats vs. wildlife as example

Identification of sites of high conservation priority impacted by feral cats in Australia

Dickman, C. R., Denny, E. A., & Buckmaster, T. (2010). Identification of sites of high conservation priority impacted by feral cats. Report to the Department of Environment, Water, Heritage and the Arts, Canberra.

Feral cats (Felis catus) have been recorded throughout the Australian mainland and on many offshore islands. Predation by feral cats has been implicated, together with other factors, in the population declines of many species of native vertebrates. Some of these declines have resulted in the shifting of species’ conservation status to a more endangered level, with several native species having become extinct. Predation by feral cats is classified as a key threatening process by the Australian Government under the Environment Protection and Biodiversity Conservation Act 1999. 

The cryptic nature of the cat, its exploitation of both modified and unmodified habitats, its status as both a pest and a pet species, and the abundance of introduced prey species and supplemental food sources throughout its range, all contribute to the many acknowledged problems associated with the control or eradication of feral cats in Australia. 

In the absence of a single, robust way to measure cat densities and the known difficulties associated with assessing cat impacts at the species level, indirect methods are required to prioritise sites for the implementation of cat control programs. 

This report uses an interactive decision-making tree based on characteristics of prey species to provide a relative measure of probable cat impacts between sites on the Australian mainland and offshore islands. The decision-making tree provides a single score for geographical (IBRA) regions, specific mainland sites and offshore islands that may be used comparatively for the allocation of resources for cat control programs. Although the scores in this report are based only on those species listed in the Australian Government’s Threat Abatement Plan for Predation by Feral Cats (2008), comparative scores can be calculated and allocated for sites that support any species at risk of predation by feral cats and classified as threatened, endangered, or vulnerable at the national, state or local level. Indeed, the decision-making tree also allows non-threatened species to be assessed for their risk of predation from cats, should the need arise to do so.

The interactive decision-making tree provided comparative scores for the potential impact of cats in each IBRA region of Australia. These scores varied from a high of 328 for the South Eastern Highlands IBRA region of eastern Australia, to a low of 24 for the Gawler IBRA region of South Australia and for three other IBRA regions located wholly or largely in Western Australia. However, there were also 9 IBRA regions with no extant TAP-listed species; these consequently received no scores. The decision-making tree also rovided comparative scores for the impact of feral cats in specific sites throughout the mainland and on offshore islands. These scores, based on data provided by land managers or available in the literature, varied from highs of 117 for the Diamantina National Park in Queensland and 108 for the East Gippsland area in Victoria, to a low of 10 for Dirk Hartog Island off the Western Australian coast. Further scores were calculated for sites at which cat control is uncertain (‘data deficient’) and from which cats have been eradicated or never recorded to identify sites that could be potentially impacted by feral cats in future. These scores varied from a high of 201 for sub-Antarctic Macquarie Island to a low of 9 for Boondelbah Island off the coast of New South Wales. 

We conclude that feral cat control on the Australian mainland is a long-term, multifaceted,labour- and resource-intensive venture requiring site-specific control methods that provide systematic and regular downward pressure on feral cat populations. An effective program of management should also include concurrent control of populations of both stray and owned domestic cats. We conclude further that greater 

success in cat control programs will be achieved by targeting specific sites using site-specific control methods. Human activities such as urban and rural development, agriculture and habitat modification favour the establishment and maintenance of feral cats. We recommend that a ‘nil tenure’ approach to cat control, with management activities encompassing public- and privately-owned reserved land as well as adjacent urban, rural and semi-rural developments, is necessary to reduce the feral cat population on the Australian mainland and offshore islands. In the absence of a sustained and integrated approach of this kind, declines and losses of native species are likely to continue.

More on Macquarie island cats

See more on Dirk Hartog Island feral cat eradication proposal

Dog predation on livestock in NSW

Fleming , P.J.S. & T.J. Korn. 1989. Predation of livestock by wild dogs in eastern New South Wales. The Australian Rangeland Journal 11(2) 61 - 66

A monthly survey involving officers from eastern New South Wales Pastures Protection Boards was conducted over four years from 1982 to 1985. Information was collected on the number and type of livestock attacked within each board district, sightings of wild dogs, the number of wild dogs killed, the method by which they were killed and the locations at which the observations occurred. A total of 25,644 livestock animals were reported killed or wounded from four regions; the North-East Coastal Region, the North-East Tablelands Region, the Central-East Region and South-East Region. Sheep were the most commonly attacked domestic animals followed by cattle and goats. Regional differences were apparent in the type of livestock killed and seasonal patterns of predation were evident. We recommend that annual control programmes be brought forward from June/July to late April in order to precede predation peaks.

Cats: perceptions and misconceptions

Perry, G. (1999). Cats–perceptions and misconceptions: two recent studies about cats and how people see them. In Proceedings of the 8th National Conference on Urban Animal Management in Australia, Gold Coast, Queensland.

 Current figures suggest that cat ownership in Australia is declining, yet cats, properly managed, make ideal pets for those living in high density housing and/or whose lifestyles require that their pets spend long periods alone. State governments and local authorities are increasingly requiring that owners control their cats and that animal management staff enforce these regulations.

These studies suggest that the majority of cat owners are responsible. Once they have adopted a cat, usually a ‘moggie’, they have their cat neutered, but sometimes not until it has had a litter. While many of their cats hunt, as many do not and few hunt often, so this problem is probably overemphasised by non-owners. Contrary to popular belief, they more often hunt lizards than birds.

With the emphasis on the identification of owned cats, it is important to note the reasons given for identifying or not. Any education program to raise awareness of the importance of identification of cats should emphasise the problems which could occur for an unidentified cat and the value of microchipping as an identification tool. All companion animals cause community problems — dogs bark, parrots screech — but both provide companionship whose value outweighs the problems they cause. Cats are particularly misunderstood and often cat owners feel guilt for the sins of their much loved couch potato’s feral counterpart. It is important that the benefits of responsible cat ownership be acknowledged and that strategies are put in place to educate owners on the value of early desexing, confinement and correct identification.

Home range of free-roaming domestic cats

Horn, JA, Mateus-Pinilla, N, Warner RE, Heske EJ (2011) Home range, habitat use, and activity patterns of free-roaming domestic cats. Journal of Wildlife Management, 75: 1177-1185.

We used radio-telemetry and collar-mounted activity sensors to compare home range size, habitat use, and activity patterns of owned and unowned free-roaming cats on the outskirts of Champaign-Urbana, Illinois, USA. Owned cats (3 M, 8 F) had smaller home ranges than unowned cats (6 M, 10 F), but we failed to detect consistent differences in home range size between the sexes or among seasons. Home ranges of unowned cats included more grassland and urban area than predicted based on availability in all seasons, and farmsteads were selected in fall and winter. Within home ranges, unowned cats shifted their use of habitats among seasons in ways that likely reflected prey availability, predation risk, and environmental stress, whereas habitat use within home ranges by owned cats did not differ from random. Unowned cats were more nocturnal and showed higher overall levels of activity than owned cats. Space use and behavioral differences between owned and unowned cats supported the hypothesis that the care a cat owner provides influences the impact a cat has on its environment, information that is important for making decisions on controlling cat populations.

Human attitudes towards stray cats management options

Ash, S. J., & Adams, C. E. (2003). Public preferences for free-ranging domestic cat (Felis catus) management options. Wildlife Society Bulletin, 31(2): 334-339.

Debate has occurred in recent years regarding the control of cat (Felis catus) populations. We investigated attitudes of Texas A&M University (TAMU) employees toward domestic cats living on university property and methods available for population control. We randomly selected 1,000 TAMU faculty and staff of the College Station campus from among 9,562 names in the university directory and mailed them a self-administered questionnaire. Questions addressed personal characteristics; attitudes about nuisance behaviors associated with cats, euthanasia, and cat overpopulation; preferred control method for cat populations in 6 locations; and expected outcomes of each control method. Preference of control method for cats on campus was influenced by respondents' sex, perception of nuisance, and expected outcome of each control method. While respondents in this study recognized the predatory impact of cats on wildlife species in natural areas and on campus, they did not believe the cat's exotic status or its predation on wildlife was a legitimate reason for controlling population numbers.

Dogs, one of the biggest threats to pudu

Silva-Rodríguez, E. A., Verdugo, C., Aleuy, O. A., Sanderson, J. G., Ortega-Solís, G. R., Osorio-Zúñiga, F., & González-Acuña, D. (2010). Evaluating mortality sources for the Vulnerable pudu Pudu puda in Chile: implications for the conservation of a threatened deer. Oryx, 44(01), 97-103.

We assessed the importance of potential sources of mortality for the Vulnerable southern pudu Pudu puda in southern Chile using the clinical records of wildlife rehabilitation centres, necropsies of animals found in the field and a review of the diet of potential predators. To assess whether the identified mortality sources operate in nominally protected areas, we conducted a camera-trap survey in two areas to determine the presence of pudus and their potential predators. Predation by domestic dogs Canis lupus familiaris and car collisions were the commonest causes of pudu admissions to rehabilitation centres (35 of 44) and of deaths of animals encountered opportunistically in the field (seven of 14). Field data suggest that poaching could also be an important threat to pudus. Pudus were detected in both areas surveyed, accounting for 15.6% of mammal detections. Dogs accounted for 47.8% of all detections of potential predator species, followed by pumas Puma concolor (17.4%), guignas Leopardus guigna (17.4%) and chilla foxes Lycalopex griseus (17.4%). The literature survey implicated only pumas as important pudu predators among native carnivores. Our data suggest that, aside from forest loss, dogs, road kills and probably poaching are important concerns for pudu conservation. Our frequent detections of free-ranging dogs associated with roads within nominally protected areas suggest that long-term efforts to conserve pudu will require not only the protection of remnant native forest but also substantive environmental education to modify dog management near protected areas.

Cat's diet and prey impact in Sweden

Liberg, O. 1984. Food habits and prey impact by feral and house-based domestic cats in a rural area in southern Sweden. Journal of Mammalogy, 65(3): 424-432

Natural prey of domestic cats in the Revinge area in southern Sweden during 1974-79 was related to prey abundance, annual production, and availability. Of 1437 scats collected, 996 contained remains of vertebrate prey. Most cats (80-85%) were house-based and obtained from 15 to 90% of their food from natural prey, depending on abundance and availability of the latter. Wild rabbits (Oryctolagus cuniculus) were the most important prey, and cats responded functionally to changes in abundance and availability of this prey. Prolonged snow cover made rabbits vulnerable to cats irrespective of abundance. Small rodents were the second most important cat prey, while brown hares (Lepus europeus) and birds were less important. In a period with high rabbit abundance, cat predation corresponded to 4% of annual production of rabbits and to about 20% of annual production of field voles (Microtus agrestis) and wood mice (Apodemus silvaticus). Prey choice of feral cats was similar to that of house-based cats, but as the former subsisted almost completely on natural prey, their absolute intake (294g/day during years with high rabbit abundance) was 4 times that of an average house-based cat (66 g/day).

Leash regulations lack of impact on small vertebrates

Forrest, A. & C.C. St. Clair. 2006. Effects of dog leash laws and habitat type on avian and small mammal communities in urban parks. Urban Ecosystems, 9:51–66

Remnant natural areas within urban settings can act as important refuges for wildlife, substantially increasing local biodiversity. However, habitat suitability for these species is potentially affected by human recreational activities including the presence of free-running dogs. To compare the diversity and abundance of songbird and small mammal communities between areas with bylaws that require, or do not require, dogs to be leashed, point counts and live-trapping surveys were conducted in three habitat types (deciduous, coniferous, and meadow) in the river valley parks of Edmonton, Alberta. Among birds, there was no difference between areas with different leashing bylaws in species diversity for any of the three habitat types. Similarly, there was no difference in bird diversity for a subset of species that were plausibly breeding at these sites. However, higher bird diversity was recorded in deciduous and coniferous sites than in meadow sites, regardless of leash designation, probably as a function of the horticultural practice of mowing meadows. Among both birds and small mammals, there was no difference in the abundance of individuals as a function of leashing bylaws. Our results suggest that off-leash dogs have no effect on the diversity or abundance of birds and small mammals in urban parks, but it is also possible that other factors, such as leash law compliance, reduced or obscured the effects of off-leash dogs in this study.

Rabbit control to control cats

Glen, A., J. Cruz & R. Pech. 2013. Can rabbit control reduce feral cat numbers at a regional scale? Kararehe Kino, Vertebrate pest research, 21: 20-21

One of the most important factors affecting the abundance of predators is the availability of their prey. In New Zealand, introduced rabbits support populations of introduced predators, including feral cats. The abundance of rabbits may therefore affect the level of predation by cats on native birds, lizards and invertebrates.

...

By adopting a multispecies approach, in which rabbit and cat populations are targeted simultaneously, that both species can be supressed over large areas for long periods. This should have considerable benefits for pasture and for native vegetation and fauna.

Pets or food?

Vigne J.-D. & Guilaine J. 2004. Les premiers animaux de compagnie, 8500 ans avant notre ère ? … ou comment j’ai mangé mon chat, mon chien et mon renard. Anthropozoologica 39 (1) : 249-273. 

The earliest pets, 8500 BC ? …or how I ate my cat, my dog and my fox.

Because they are of little interest economically, the carnivore mammals provide especially favourable characteristics for the archaeological study of the social and symbolic aspects of domestication in the early Neolithic periods. A short review of available data on the beginnings of the domestication of the dog, the cat and other carnivores, mainly in the Near East, allows us to ask questions about the conditions of their domestication.

Recent discoveries from the Preceramic Neolithic of Cyprus shed new light on these questions. They confirm that dog (Canis familiaris), fox (Vulpes vulpes) and cat (Felis s. lybica) were voluntarily brought to the island, and that this took place during the second half of the 9th millennium, the first half and the second half of the 8th millennium, respectively. This introduction suggests taming and appropriation of the animals by the human beings. A burial associating a human and a cat even suggests that these animals were kept as pets. But an important proportion of the bone remains of the three carnivores indicate that people did eat them. Moreover, several clues suggest that all or a part of these animals escaped human control and lived in feral groups. It seems that few dogs or none at all lived in the immediate vicinity of human dwellings. These observations, which conflict with our modern occidental conventions, suggest, for these early Neolithic phases, that the boundary between domestic and wild was fine and variable.


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Cat and dog's gene introgression

Daniels, M.J. & L. Corbett. 2003. Redefining introgressed protected mammals: when is a wildcat a wild cat and a dingo a wild dog? Wildlife Research 30(3) 213 - 218

Interbreeding between protected species and their domestic forms presents a conundrum for wildlife managers and legislators with respect to both defining the taxa concerned and enacting or enforcing conservation measures. Recent research on two species geographically distant but with highly analogous histories, the wildcat (Felis silvestris) in Scotland and the dingo (Canis lupus dingo) in Australia, illustrates the challenges faced. Introgression has left the contemporary wild form of both species difficult to distinguish from many of their domesticated forms. Furthermore, historical definitions, and the protective legislation based on them, have been rendered obsolete by subsequent anthropogenic environmental change. We argue that a new approach is necessary for defining mammalian species in the face of introgression with their domestic forms and environmental change, including persecution. Protecting animals for where and how they live, and for their cultural or ecosystem function value rather than focusing on their appearance, offers the best solution for maintaining their conservation status.

Intraguild interactions between dogs and wild carnivores

Vanak, A.T. 2008. Intraguild interactions between native and domestic carnivores in Central India. PhD. University of Missoury

I determined the various factors affecting the resource selection and spatial ecology of the Indian fox Vulpes bengalensis, a small canid endemic to the Indian subcontinent. Despite being widespread throughout India, and commonly occurring in many dry grassland habitats, little is known about the ecology of this species. I investigated habitat selection by the Indian fox in a grassland region in central India that represents a mix of natural and human-dominated habitats to discern if and how foxes respond to human encroachment on native habitats. I collected home range and habitat selection data on 32 radio-collared Indian foxes in the Great Indian Bustard Wildlife Sanctuary, Nannaj, Maharashtra over a one year period. Adult Indian fox 95% kernel density home-range sizes varied between sexes and among seasons. Males had consistently larger home-ranges than females across all seasons but there was no interseasonal variation. Females had smaller home-range sizes during the cool-dry season which is also the denning period, than during any other season. Compositional analysis of Indian fox selection of home-ranges at the landscape level showed heavy influence of the presence of grasslands, plantations and fallow land. Indian foxes avoided humanmodified habitat such as agricultural land and human settlements. The presence of grasslands was also the dominant predictor of Indian fox habitat selection across seasons within the home-range as determined by AIC ranked discrete-choice models. The results indicate that Indian foxes select for natural grasslands and avoid human-modified habitat.
The distribution, abundance and resource selection patterns of meso-carnivores such as the Indian fox are also heavily influenced by the effects of top-down intraguild competition with sympatric larger carnivores. Competitive dynamics among carnivores are asymmetric and interference competition and the associated occurrence of intraguild predation are unidirectional, with larger carnivores negatively influencing smaller carnivores. Competition can affect the subordinate competitor in several ways: by limiting spatial distributions resulting in scattered interspecies territories, constraining habitat selection, reducing prey encounter rates and food intake, or requiring increased hunting effort.
In my study area, the domestic dog Canis familiaris, is the most common midsized carnivore. As the world’s most common carnivore, dogs are known to interact with wildlife as predators, prey, competitors, and disease reservoirs or vectors. Despite these varied roles in the community, the interaction of dogs with sympatric carnivores is not well understood. Dogs have the potential to be exploitative, interference and apparent competitors with sympatric carnivores.
I examined competition for food between dogs and the Indian fox through dietary analysis. Dogs subsisted largely on human derived material from direct feeding, and scavenging on garbage, crop residue and livestock carcasses (83% relative occurrence).

Wild caught foods constituted only 11% relative occurrence of dog diet. Indian foxes are omnivorous and included a wide variety of food types in their diet. The majority of  Indian fox diet consisted of invertebrates (33% relative occurrence), rodents (20% relative occurrence) and fruits of Zizyphus mauritiana (18.5% relative occurrence). Indian foxes did not include any human derived material, nor did they scavenge from large mammal carcasses, and included only a small portion of agricultural produce in their diet. The diet of free-ranging dogs is typical of dogs from other parts of the world. However, the low contribution of human-derived food sources to the diet of Indian foxes was surprising since the species is a generalist carnivore. Although there was limited dietary overlap between dogs and foxes in this study, dogs may actually be preventing foxes from accessing agricultural lands and human associated foods by interference competition.

Dogs have the potential to be effective interference competitors, especially with medium and small-sized carnivores, and may fulfill the role of a mid-sized canid, especially in areas where the native large carnivore community is depauperate. I experimentally examined the behavioral responses of the Indian fox to the presence of dogs and dog odors. Since resource competition between dogs and foxes is low, it is unclear whether foxes perceive dogs as interference competitors. To test this I exposed foxes to neutral, live dog, and animal odor cues at food trays and recorded the amount of food eaten, time spent at food trays, and vigilance and non-vigilance behaviors. When dogs were visible, foxes continued to visit the food trays, but reduced the amount of time spent (by 83%) and food eaten (by 70%) at those trays. Foxes were 10 times more vigilant during dog trials than during neutral and odor trials and also exhibited lower levels of non-vigilance behavior (resting, playing) when dogs were visible. In contrast, dog odors did not affect fox foraging and activity. These results show that vigilance/foraging tradeoffs due to interference competition can occur between native and domestic carnivores, despite low dietary overlap.

To avoid the effects of interference competition and intraguild predation, subordinate competitors such as the Indian fox can alter space use patterns which may result in a reduction of foraging opportunities. To determine if interference competition between dogs and foxes influences the space use patterns of foxes at a landscape level, I conducted a radio-telemetry study of 32 Indian foxes and 25 free-ranging dogs in and around the Great Indian Bustard Wildlife Sanctuary in central India. Using a logistic regression analysis in an information theoretic framework, I determined the effects of landcover type, primary prey abundance (rodents) and dog presence on the landscape on the space use of foxes. As expected, Indian foxes showed low overlap with dogs based on the volume of intersection index. Top AIC ranked models showed a positive influence of grasslands and a negative influence of agricultural land and dog presence. Rodent abundance only had a weak positive effect. This suggests that fox space use is determined not only by habitat type, but also influenced by the presence of a mid-sized carnivore, the dog.

These results suggest that the competitive intraguild dynamics that are seen among wild carnivores can also occur between wild and domestic carnivores, despite a seeming lack of competition for food and other resources. The role of dogs as intraguild competitors of wild carnivores has thus far been under-recognized. Dogs are among the world’s most common carnivores and are heavily subsidized by humans. As a result, they can occur at high densities even in rural areas, where they tend to range freely into wild habitats. Therefore, dogs can pose threats to native carnivore communities, and extend the edge of anthropogenic disturbance well beyond the borders of human settlements.

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Disease impact of dogs

Vanak, A. T., Belsare, A. V. & Gompper, M. E. 2007. Survey of Disease Prevalence in Free-Ranging Domestic Dogs and Possible Spill-Over Risk for Wildlife – A Case Study from the Great Indian Bustard Sanctuary, Maharashtra - India. Final report submitted to the Rufford Small Grants Foundation, UK. Pp 1-13

Domestic dogs are the world’s most common carnivore, and yet the ecology of free-ranging  dogs has rarely been investigated. Many dog populations are subsidized by humans resulting in  high population density, which presumably also have contact rates above the critical threshold  that allows diseases to persist enzootically within the population. Domestic dogs are the  reservoir of infectious diseases that have led to epidemics of rabies, canine distemper and  canine parvovirus in several wild carnivore species, yet little is known about the disease ecology  of domestic dogs in India, and the potential for spill-over risk to wildlife. This project was carried out to assess the disease exposure and health status of free-ranging domestic dogs in the vicinity of a wildlife reserve in central India. We carried out a sero-prevalence survey of canine distemper virus (CDV), canine parvovirus (CPV) and rabies in the dog population surrounding the Great Indian Bustard Sanctuary in Nannaj, Maharashtra. We sampled 74 dogs from four villages surrounding the wildlife reserve and obtained blood samples for testing for IgM and IgG antibodies to CDV and CPV. We also collected salivary swabs from 31 dogs to test for rabies antigen. Antibodies to CPV were detected in 93.3% of the sampled dogs, while 90.7% of dogs had evidence for recent or past exposure to CDV. This suggests that these diseases are enzootic in the dog population, and may pose a significant threat to wild carnivores if disease control measures are not implemented. Rabies was also detected in 2 (6%) of the dogs tested, raising human health concerns as well. We recommend a comprehensive vaccination and dog population control policy as well as an education campaign on responsible dog ownership among villagers.