Feral cats datasheet

Fitzwater, W.D. 1994. House cats (feral). In S.E. Hygnstrom, R.M. Timm, and G.E. Larson, eds. Prevention and Control of Wildlife Damage. Lincoln: Univ. Neb. Coop. Ext.USDA_APHIS-Wildlife Services Animal Damage Control, and Great Plains Agricultural Council. Pp: C45-C50.

The cat has been the most resistant to change of all the animals that humans have domesticated. All members of the cat family, wild or domesticated, have a broad, stubby skull, similar facial characteristics, lithe, stealthy movements, retractable claws (except the cheetah), and nocturnal habits. Feral cats are house cats living in the wild. They are small in stature, weighing from 3 to 8 pounds, standing 8 to 12 inches high at the shoulder, and 14 to 24 inches long. The tail adds another 8 to 12 inches to their length. Colors range from black to white to orange, and an amazing variety of combinations in between. Cats are found in commensal relationships wherever people are found. In some urban and suburban areas, cat populations equal human populations. In many suburban and eastern rural areas, feral house cats are the most abundant predators. Feral cats prefer areas in and around human habitation. They use abandoned buildings, barns, haystacks, post piles, junked cars, brush piles, weedy areas, culverts, and other places that provide cover and protection. Feral cats are opportunistic predators and scavengers that feed on rodents, rabbits, shrews, moles, birds, insects, reptiles, amphibians, fish, carrion, garbage, vegetation, and leftover pet food. Feral cats feed extensively on songbirds, game birds, mice and other rodents, rabbits, and other wildlife. In doing so, they lower the carrying capacity of an area for native predators such as foxes, raccoons, coyotes, bobcats, weasels, and other animals that compete for the same food base.

Impact of cats on Australian wildlife

Tidemann, C. R. (1994). Do cats impact on wildlife?. In Urban animal management: proceedings of the third national conference on urban animal management in Australia. Australian Veterinary Association, Sydney.

Cats can have beneficial impacts on wildlife by stabilising numbers of rabbits and exotic rodents. They can also have  adverse impacts, directly through predation and indirectly through the transmission of diseases. In many cases it is incorrect to single out cats as the sole factor responsible for declining wildlife populations, but the adverse impacts of cats may operate in concert with other factors, such as droughts, to finally push species into local or complete extinction. However, there is enough evidence available to indicate that a reduction in the numbers of free-ranging cats in urban areas would lead to a desirable increase in biodiversity in Australian cities. This statement, like any other to do with the management of complex ecosystems, needs to be viewed as a working hypothesis, requiring ongoing evaluation and subsequent modification as further information becomes available. Further information in this case could readily be collected by enlisting the aid of community groups to monitor the response of prey species to cat control programs. 

Pet cats' impact on prey populations

Barratt, D. 1994. Using theory and scientific experience to assess the impact of house-based domestic cats Felis catus (L.) on prey populations and prey community structure. Urban animal management conference proceedings - Canberra. Australia.

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.

Predation of Birds at Feeders in Winter

Dunn, E. H., & Tessaglia, D. L. (1994). Predation of Birds at Feeders in Winter (Depredación de Aves en Comederos Durante el Invierno). Journal of Field Ornithology, 65 (1) 8-16.

A continentwide survey of homes with bird feeders produced 567 reports documenting 1138 incidents of predation. Of the 25 species of predators recorded, three (Sharp-shinned Hawk, Accipiter striatus; domestic cat; Cooper's Hawk, A cooperii) were responsible for 80% of the incidents in which the predator was known. Ten of the 62 species of prey identified accounted for 92% of all victims. The birds most vulnerable to predation were those that commonly occur at feeders throughout the continent (i.e., the most widespread species), but additionally, flocking species were more vulnerable to avian predators than more solitary ones. Prey size was correlated to size of avian predators, but cats concentrated on small birds. Hawks were attracted to feeders with particularly high levels of bird activity, but cats were not. The bird-feeding environment does not appear to expose birds to a higher risk of predation than is encountered in the absence of feeders.

Se hizo una encuesta, a nivel continental, en residencias en donde se les provee de comederos a aves, que produjo 567 informes en los cuales se documentan 1138 incidentes de depredación. De las 25 especies de depredadores informados tres de éstos, a saber Accipiter striatus, A. cooperii y el gato doméstico, fueron responsables del 80% de los incidentes en donde el depredador fue identificado. Diez de las 62 especies que sirvieron como presas, formaron el 92% de todas las víctimas. Las aves más vulnerables a la depredación fueron aquellas que más comúnmente utilizan comederos artificiales a nivel continental (ej. las especies más ampliamente distribuidas). No obstante las aves que se alimentan en grupos resultaron más vulnerables que las que lo hacen de forma solitaria. El tamaño de la presa se correlacionó al tamaño del depredador, aunque los gatos concentraron sus esfuerzos en aves pequeñas. Los halcones fueron atraídos a comederos, con altos niveles de actividad aviar, mientras que ocurrió lo opuesto con los gatos. Los ambientes en donde hay comederos artificiales no parecen exponer a las aves a un riesgo mayor de depredación, que en lugares en donde éstos no se encuentran.

Attractans for feral cats

Clapperton, B. K., Eason, C. T., Weston, R. J., Woolhouse, A. D., & Morgan, D. R. (1994). Development and testing of attractants for feral cats, Felis catus L. Wildlife Research, 21(4), 389-399.

As part of a programme to improve feral-cat control and eradication techniques, various odours were tested as candidate lures. They included food odours (fish oils), social odours (urine and its components, anal-sac secretions and commercial wild-animal lures) and plant materials (catnip, matatabi and their essential oils). Pen bioassay experiments used a preference procedure on captive feral and domestic cats to compare the time spent investigating the odours and the number of cats visiting each odour. Field trials at rubbish dumps used scent stations to assess cat activity. Catnip and matatabi were the most promising candidate lures in both the pen bioassay and the field trials. Future directions for lure developments are suggested.

Cat responsible of extinctions on Mangere Is.

Tennyson, A. J. D., & Millener, P. R. (1994). Bird extinctions and fossil bones from Mangere Island, Chatham Islands. Notornis, 41(supplement), 165-178.

Fossil bones and earlier observations indicate that up to 22 species of bird have become extinct on Mangere Island. The extinctions appear to have been primarily a result of predation by cats, but human hunting and bush clearance are likely to account for the disappearance of some species. A crested penguin Eudyptes ?n.sp., two species of Pterodroma petrel, a shelduck Tadorna ?n.sp., Dieffenbach's Rail Gallirallus dieffenbachii, and a kaka Nestor ?n.sp. are present in fossil deposits on Mangere Island, but have not been reported from the island before. The relative proportion of remains in the deposits suggest that Blue Penguins Eudyptula minur, Broad-billed Prions Pachyptila vinata and Sooty Shearwaters Puffinus griseus have become more common on the island. Any such increases on Mangere Island, could have been a response of a few species to the large decrease in numbers and diversity that has affected seabirds as a whole at the Chatharns. Some seabird species mav have been able to increase because of reduced competition for-food.

Cat range on a small island

YAMANE, A., ONO, Y., & DOI, T. (1994). Home range size and spacing pattern of a feral cat population on a small island. Journal of the Mammalogical Society of Japan, 19(1), 9-20.

Home range size and spacing patterns of feral cats (Felis catus) were investigated and data analyzed quantitatively, to clarify the factors affecting their social organization. "Feeding groups" were identified. These consisted of male and female members which used the same garbage site mainly for feeding (Izawa et al. 1982). The spacing patterns of females showed that they defended their feeding sites from use by females of other groups. During each season mean home range size was significantly greater for males than for females. Males expanded their ranges during the females' estrous season when their mean size exceeded the predicted size based purely on metabolic requirements. Furthermore, male home range size (during the estrous season) was correlated directly with the number of females they courted. These results suggest that the mating resource, the number of receptive females, is more important in determining male home range size during the estrous season than is the food resource.

Hybridization between dog and Ethiopian wolf

Gottelli, D, Sillero-Zubiri, C, Applebaum G.D., Roy MS, Girman D.J., García-Moreno, J., Ostrander, E.A. & Wayne, R.K.. (1994) Molecular genetics of the most endangered canid - the Ethiopian wolf Canis simensis. Molecular Ecology 3: 301–312.

The world's most endangered canid is the Ethiopian wolf Canis simensis, which is found in six isolated areas of the Ethiopian highlands with a total population of no more than 500 individuals. Ethiopian wolf populations are declining due to habitat loss and extermination by humans. Moreover, in at least one population, Ethiopian wolves are sympatric with domestic dogs, which may hybridize with them, compete for food, and act as disease vectors. Using molecular techniques, we address four questions concerning Ethiopian wolves that have conservation implications. First, we determine the relationships of Ethiopian wolves to other wolf-like canids by phylogenetic analysis of 2001 base pairs of mitochondrial DNA (mtDNA) sequence. Our results suggest that the Ethiopian wolf is a distinct species more closely related to gray wolves and coyotes than to any African canid. The mtDNA sequence similarity with gray wolves implies that the Ethiopian wolf may hybridize with domestic dogs, a recent derivative of the gray wolf. We examine this possibility through mtDNA restriction fragment analysis and analysis of nine microsatellite loci in populations of Ethiopian wolves. The results imply that hybridization has occurred between female Ethiopian wolves and male domestic dogs in one population. Finally, we assess levels of variability within and between two Ethiopian wolf populations. Although these closely situated populations are not differentiated, the level of variability in both is low, suggesting long-term effective population sizes of less than a few hundred individuals. We recommend immediate captive breeding of Ethiopian wolves to protect their gene pool from dilution and further loss of genetic variability.

Alien mammals on French subantarctic islands

Chapuis, J. L., Boussès, P., & Barnaud, G. 1994. Alien mammals, impact and management in the French subantarctic islands. Biological Conservation,67(2): 97-104.

The unique plant and animal communities of the French subantarctic islands have been greatly modified by the introduction of mammals since their discovery in 1552 and 1772. Nine species, wild and domestic, thrive due to a lack of competitors, predators and diseases and despite the small number of founders. Herbivores have induced significant changes to the nature and structure of plant communities and carnivores have modified burrowing petrel Procellaridae populations and species diversity.

Introductions are now prohibited. Research programmes have been developed to study the population biology, and measures are being taken to control or eradicate alien species populations. Control programmes are effective for rabbits Oryctolagus cuniculus on the Kerguelen archipelago and cattle on Amsterdam Island. Planned programmes deal with cat, mouflon and sheep in the Kerguelens.

Diet of feral cats on Christmas Island

Tidemann, C.R., Yorkston, H.D. & Russack, A.J. 1994. The diet of cats, Felis catus, on Christmas Island, Indian Ocean. Wildlife Research. 21 (3): 279-285.

Cats, Felis catus, were taken to Christmas Island (10°25'S,105°40'E) in the Indian Ocean at the time of first settlement in 1888 and a feral population became established soon thereafter. In 1988 a wide range of vertebrate and invertebrate animals was present in the diet of these feral cats, but flying-foxes, Pteropus melanotus, fruit pigeons, Ducula whartoni, and introduced rats, Rattus rattus, together constituted 80% of their food intake by weight. Of the guts examined, 45% contained R. rattus, and this species accounted for 31% of food intake by weight. Less than 10% of cat guts contained P. melanotus and D. whartoni, but the large body weights of these species meant that by weight they made up 21% and 28% respectively. Mus musculus was found in 27% of guts examined, although it contributed only 2% by weight. It is likely that the large numbers of feral cats present in vegetative regrowth on mined areas are related to the ease with which all four primary prey species may be caught there. No evidence was found that cats are having a deleterious effect on native species and they may well be beneficial in stabilising the numbers of R. rattus, which itself can be a serious predator of nesting birds.

Other perspective on the impact of urban cats

Although the summary don't come into detail, the author states that feral cats have positive effects: predation on rodents, anti-depressive effect for cat-carers, educative impact for children and adults and aesthetic effects. On the negative side, just hygiene and public health.

Natoli, E. 1994. Urban feral cats (Felis catus L.): perspectives for a demographic control respecting the psycho-biologicalwelfare of the species. Ann. Ist. Super. Sanità, 30 (2): 223-227

The presence of feral cats in the urban environment is creating problems of acceptance by human beings, especially in relation to health aspects. In accordance with the protectionist spirit of the law 281 of 14/8/91, the new sensitivity of the Public Veterinary Services for feral cat control in the cities are proposed. These consist mainly in demographic control by means of neutering the cats, with particular attention to the psycho-biological welfare of the species. 

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.


Read a short review about belling effectiveness

Canine distemper impact on African wild dogs

Alexander, K.A. & M.J. Appel. 1994. African wild dogs (Lycaon pictus) endangered by a canine distemper epizootic among domestic dogs near the Masai Mara National Reserve, Kenya. Journal of Wildlife Diseases, 30 (4): 481-485

A longitudinal study of canine distemper (CD) among domestic dogs on Malsai communal land to the north of the Masai Mara National Reserve in Kenya was conducted from 1989 to 1991. Prevalence of antibodies to CD was very low among domestic dogs in 1989 and 1990 (4%, n = 49; and 1%, n = 119, respectively) and no African wild dogs (Lycaon pictus; n = 16) collected simultaneously from the same area had detectable antibodies. Among 51 domestic dogs sampled in 1991, however, prevalence of CD antibodies rose significantly (P < 0.01) to 76%. Disease-related mortality rates among domestic dogs were estimated from 1990 to 1992; they rose significantly (P < 0.01) from 21% in 1990 to 50% in 1991 and then decreased significantly (P < 0.01) to 38% in 1992. The 1992 mortality rate remained significantly (P < 0.01) higher than that of 1990. Signs observed in clinically ill domestic dogs were consistent with CD and included listlessness, decreased appetite, bilateral serous to mucopurulent oculonasal discharge, and diarrhea. No carcasses could be retrieved for virus isolation and postmortem examination. Concurrent with this CD epizootic in domestic dogs, the known African wild dog packs in this region disappeared.