Cat detection depending on dominant native predator presence

Lazenby BT, & Dickman CR (2013) Patterns of Detection and Capture Are Associated with Cohabiting Predators and Prey. PLoS ONE 8(4): e59846. 

Avoidance behaviour can play an important role in structuring ecosystems but can be difficult to uncover and quantify. Remote cameras have great but as yet unrealized potential to uncover patterns arising from predatory, competitive or other interactions that structure animal communities by detecting species that are active at the same sites and recording their behaviours and times of activity. Here, we use multi-season, two-species occupancy models to test for evidence of interactions between introduced (feral cat Felis catus) and native predator (Tasmanian devil Sarcophilus harrisii) and predator and small mammal (swamp rat Rattus lutreolus velutinus) combinations at baited camera sites in the cool temperate forests of southern Tasmania. In addition, we investigate the capture rates of swamp rats in traps scented with feral cat and devil faecal odours. We observed that one species could reduce the probability of detecting another at a camera site. In particular, feral cats were detected less frequently at camera sites occupied by devils, whereas patterns of swamp rat detection associated with devils or feral cats varied with study site. Captures of swamp rats were not associated with odours on traps, although fewer captures tended to occur in traps scented with the faecal odour of feral cats. The observation that a native carnivorous marsupial, the Tasmanian devil, can suppress the detectability of an introduced eutherian predator, the feral cat, is consistent with a dominant predator – mesopredator relationship. Such a relationship has important implications for the interaction between feral cats and the lower trophic guilds that form their prey, especially if cat activity increases in places where devil populations are declining. More generally, population estimates derived from devices such as remote cameras need to acknowledge the potential for one species to change the detectability of another, and incorporate this in assessments of numbers and survival.

DNA to identify canid predation on livestock

Sundqvist, A. K., Ellegren, H., & Vilà, C. (2008). Wolf or dog? Genetic identification of predators from saliva collected around bite wounds on prey.Conservation Genetics, 9(5), 1275-1279.
Wolf predation on livestock is a management problem in many areas and is often used to justify control measures against the wolves. However, wolves coexist with dogs across their range, and dogs could be responsible for attacks blamed on wolves. In this study we evaluate the possibility of obtaining sufficient DNA for species identification of the predator from saliva remaining close to bite wounds following a canid attack. Predator DNA of reasonably high quality was successfully extracted from bite wounds on two sheep that had been attacked on a farm and were genotyped using six informative microsatellite markers. A single consensus genotype could be constructed from the bite wounds of both sheep which we compared to genotypes obtained from Scandinavian wolves and dogs. The results clearly showed that the saliva sampled originated from a single dog. This report thus demonstrates the feasibility of predator species identification from bite wounds and also illustrates that it can not be taken for granted that wolves are responsible for canid livestock kills.

DNA to prove dog attacks

Clarke, M., & Vandenberg, N. (2010). Dog attack: the application of canine DNA profiling in forensic casework. Forensic science, medicine, and pathology,6(3), 151-157.

More than 100,000 dog attacks occur each year in Australia and many go unsolved. Dog attacks are not only a cause of human injury but may also involve injury and death to family pets, prized livestock and wildlife. Canine biological evidence can often be left behind on a victim or at the scene of an attack. Our laboratory provides canine DNA profiling for forensic investigations, utilising an in-house panel of 11 canine-specific autosomal short tandem repeat markers previously validated for use in casework. Case studies will be presented that outline methods for sampling of suspected canine biological evidence, profiling of canine DNA, statistical analysis, case outcomes and challenges for investigators.

Population dynamics of a population of free roaming cats

Taylor, B. (2013). Population Dynamics of Free-Roaming Cats in Florida's Lee County. Undergraduate Journal of Mathematical Modeling: One+ Two, 3(1), 16.

We investigate whether the Trap-Neuter-Return (TNR) program can be effectively used to control the population of free-roaming cats in Florida's Lee County. We do this by estimating the number of cats that must be spayed/neutered in order to keep the population from increasing.

Our analysis shows that keeping the population of free-roaming cats in Lee County (98,000 individuals) from growing requires spaying/neutering of at least 370 cats per week. We suspect that this estimate is high because the model we considered is density independent. Nevertheless our results underline the rate at which the cat population can explode if not properly controlled.

Eradication of feral cats at Wake Atoll

Rauzon, M. J., Everett, W. T., Boyle, D., Bell, L., & Gilardi, J. (2008).Eradication of feral cats at Wake Atoll. National Museum of Natural History, Smithsonian Institution.

Feral cats (Felis catus) were introduced at Wake Atoll, (19°18' N, 166° 38' E) in the 1960s as pets and probably to control rats on this U.S. military base in the North Pacific Ocean. After base-downsizing in the 1970s, feral cats became a noticeable problem. Hunting and trapping to control their numbers has been sporadic over time but began seriously in 1996 and continued through 2002, during which time about 200 cats were removed. The eradication effort began in July 2003 and by January 2004 another 170 cats had been removed. During visits from late 2004 to 2007, two feral cats were seen but no cat reproduction was detected.
Bird populations responded quickly to the release of predation: Masked Boobies (Sula dactylatra) increased from three breeding pairs in 1996 to 25 by 2007; the Brown Booby (S. leucogaster) population rose from 73 nests in 1996 to 162 in 2003. Wedgetailed Shearwaters (Puffinus pacificus) recolonized around 1998 and populations expanded to form at least three colonies with individuals in numerous locations around the atoll. Gray-backed Terns (Onychoprion lunata), not recorded breeding on the atoll since the 1980s, began nesting in two new sites, and Great Frigatebirds (Fregata minor), which had not been recorded nesting since the 1960s, renewed reproductive efforts in 2005. Due to feral cat removal and wet weather, Pacific Rats (R. exulans) greatly increased. Current rodent control effort was less effective than it should be because hermit crabs (Coenobita perlata) ate the bait before the rats did. A bait station model design to exclude crabs was designed and tested. The island managers continued to control rats at Wake around housing areas, and rodent populations have declined since their peak following cat eradication.
On Aug. 31, 2006, Wake Island was struck by Super Typhoon Ioke. Winds over 130 mph knots broke many trees and damaged the island infrastructure but the island was soon functioning again. In June 2007, we returned and found a few cats survived. They appear to be the same cats known to remain at the end of our eradication, are likely the same sex since no kittens have been detected since then.

Cat and catkeepers in Rome

Natoli, E., Ferrari, M., Bolletti, E., & Pontier, D. (1999). Relationships between cat lovers and feral cats in Rome. Anthrozoos: A Multidisciplinary Journal of The Interactions of People & Animals, 12(1), 16-23.


The aim of this study was to assess the relationships between cat lovers and feral cats in Rome. One hundred and fifty-eight cats from 3 populations were observed for 1108 hours of data collection: some demographic characteristics of the colonies were investigated, together with the behavior of cat lovers (those who fed and cared for the cats). The quantity of food eaten and uneaten by the cats was recorded, and the cost to support each colony calculated. The quantity of food provided ranged from 20.47 to 264 kg/month. The mean quantity of food eaten/day by each cat in the study areas never surpassed 130.4 g. In total, the quantity of food wasted ranged from 522 g to 34.05 kg/month. The results of this study can help public administrations decide on how to allocate funds for the management of feral cats. Indeed, they provide statistics on the individual food intake/cat/day, as well as information on the type of collaboration one should expect from cat lovers. In addition, this study outlines advantages and limits of the "Roman model" where the Public Veterinary Services (PVS) and associations of cat lovers cooperate to manage feral cats.

Cat activity patterns in NY

Haspel, C., & Calhoon, R. E. (1993). Activity patterns of free-ranging cats in Brooklyn, New York. Journal of mammalogy 74(1), 1-8.

Activity patterns of free-ranging cats in Brooklyn, New York, varied with neighborhood, season, and hour of the night. Standardized partial-regression analysis identified temperature, humidity, precipitation, and hour as accounting for 32.6% of feral-cat activity. Cats in the area of private homes included free-ranging pets while those in the area of multiple dwellings were commonly feral. Regardless of neighborhood, nighttime activity was bimodal with peaks occurring at 0100 h and at sunrise. Activity levels declined throughout the autumn and increased in the spring.

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.

TNR needs reaching 90% of the population to be effective

Jones, A. L., & Downs, C. T. (2011). Managing feral cats on a university's campuses: how many are there and is sterilization having an effect?. Journal of Applied Animal Welfare Science, 14(4), 304-320.

Worldwide domestic and feral cat (Felis catus) numbers have increased. Concerns regarding high populations of feral cats in urban areas include wildlife predation, public nuisance, and disease. This study aimed to estimate the size of the feral cat population on 5 campuses of the University of KwaZulu-Natal, South Africa, to determine whether sterilization has an effect and to make management recommendations. The study used both the total count and mark-recapture methods to estimate the feral cat population on each campus. The study chose a noninvasive method of taking photographs to “mark” individuals and record those who were sterilized. The study estimated a total of 186 cats on all campuses and density at 161 cats/ km²  There was a negative relationship between sterilization and numbers. Sites with higher sterilization showed a lower proportion of younger cats. At the average sterilization of 55%, the population, according to predictions, would remain stable at fecundity, survival, and immigration rates reported by cat caretakers. However, caretakers underestimated cat abundance by 7 ± 37 SD%. Caretakers' feral cat sterilization and feeding programs appear to provide a service to the university community. Key management recommendations were to increase sterilization to 90% to reduce the population over the long term and to raise funds to support the costs incurred by voluntary cat caretakers.

Up to 31% of recoveries of banded birds killed by cats

Mead, C. J. (1982). Ringed birds killed by cats. Mammal Review, 12(4), 183-186.

Mead examined the fate of banded birds in Britain and discovered that for six species more than 25 percent of the recoveries were of birds caught by cats. He ascribed 31% of recoveries of ringed robins and dunnocks to cat predation, but believed that there was no evidence that cats affected the overall populations of these species. Catchability is very different in different species, depending on gregarious habits, terrestrial feeding, avoidance of potential hiding places, etc. but some cats are even able to catch aerial species.
He emphasised that birds in rural and suburban parts of Britain have co-existed with cats for hundreds of generations and may now be under less pressure from cats than they were in the past from assorted 'natural' predators.

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.



Read a short review about belling effectiveness

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.


Read a short review about belling effectiveness

Cats as first cause of death of British ringed birds

The BTO (British Trust for Ornithology) started bird ringing 100 years ago, in 1909. To date some 36 million birds have been ringed, providing a unique insight into the birds of Britain and Ireland...

...The BTO receives reports of around 14,000 birds with rings every year, providing an invaluable source of information on the latest trends in bird conservation. I think that one of the telling statistics is the causes of death. For all those people who get very upset when birds are caught in oil spills, (5,600 records), collisions with windows (13,800) or collisions with overhead wires (9,400), all these numbers are dwarfed by the 41,900 birds killed by domestic cats.

Home ranges of feral cats in South Eastern Australia

Molsher, R., Dickman, C., Newsome, A., & Müller, W. (2005). Home ranges of feral cats (Felis catus) in central-western New South Wales, Australia. Wildlife Research, 32(7), 587-595.

Twenty-one feral cats were radio-tracked using direct sighting and triangulation techniques (amassing 730 location fixes) during winter in an agricultural landscape in central-western New South Wales. Factors affecting home-range size, home-range overlap and habitat use were assessed. Mean home-range size was 248 ha (s.e. = 34.9, n = 15 cats, 598 location fixes). Home-range size and habitat use were not influenced by sex or age of adult cats, prey abundance or time of day. However, cat weight significantly influenced range size, with heavier cats having larger ranges than smaller cats. Although the cats are apparently solitary, their home ranges overlapped considerably, particularly between young adults and old adult cats. Cats were active both by day and night and did not occupy permanent dens. Home ranges encompassed mixed habitat types that provided both shelter and prey. Open woodland and open forest were the main habitat types covered by home ranges, but within these areas cats showed a preference for grassland, where rabbits were more abundant. The results recorded in this study indicate that cat-control programs should concentrate in mixed habitat areas, where both shelter and food are available, and over widely dispersed areas. The absence of group living suggests that the effectiveness of virally vectored fertility or biological control agents would be limited.

Feral cat's demography in New South Wales

Molsher, R. L. (2001). Trapping and demographics of feral cats (Felis catus) in central New South Wales. Wildlife Research, 28(6), 631-636.

A total of 76 feral cats (Felis catus) (29 individuals; 47 recaptures) was trapped during 6027 trap-nights using both cage and leg-hold traps from November 1994 to August 1996 at Lake Burrendong in central New South Wales. No significant difference was found in the relative capture efficiency between cage and leg-hold traps (P > 0.05). Overall capture efficiency was 1.3 cats per 100 trap-nights, although this varied seasonally, being higher in late autumn and early winter. Most cats were caught with rabbit as bait, and visual and olfactory lures added to baits did not appear to increase capture efficiency, although the power of the test was limited. Most captured cats were adult males weighing 4.37 0.14 kg; these were larger than the females (3.34 0.06 kg). Litters, comprising 2–5 kittens, were born between September and March.