Do cat attributes influence what they eat?

Yip, S. J., Dickman, C. R., Denny, E. A., & Cronin, G. M. (2013). Diet of the feral cat, Felis catus, in central Australian grassland habitats: do cat attributes influence what they eat?. Acta Theriologica, 1-8.

The house cat Felis catus was introduced to Australia as a pet and means of rodent control over 200 years ago, but now has established feral populations and has become a serious threat to native wildlife. Using stomach content analysis of 73 feral cats from semi-arid grassland habitats in Queensland, Australia, we aimed to identify dominant prey groups in the cats' diet and to explore associations between the diversity of prey eaten and attributes of the cats including body size, condition, sex, age and coat colour. We also sought to determine any relationships between cat size and the size of the dominant prey in the diet, the long-haired rat Rattus villosissimus. Mammals and reptiles were the dominant prey, with R. villosissimus occurring in 60 % of samples and comprising more than half of all prey by volume. Birds and terrestrial invertebrates were the next most important contributors to the diet, but fish, frogs and freshwater crustaceans also were surprisingly well represented. The dietary diversity of cats was largely unrelated to any of the cat attributes that we measured, although a positive relationship emerged between cat head width and the range of prey types eaten. Our study was conducted during a population irruption of R. villosissimus and confirms that cats are able to exploit an abundant focal prey resource when the opportunity occurs. Further research now is needed to explore associations between diet and cat attributes during periods when rats are scarce.

Dogs and cats in the mammal assemblage in a urban forest patch in Brazil

Bernardo, P. V. D. S., & Melo, F. R. D. (2013). Assemblage of medium and large size mammals in an urban Semideciduous Seasonal Forest fragment in Cerrado biome. Biota Neotropica, 13(2), 76-80.

Nowadays, the processes of deforestation and loss of habitats represent a major threat to many species of mammals. These processes cause changes in natural landscapes by decreasing area, connectivity, and fragment size, and increasing edge effects and number of fragments. Understanding which and how many species persist in disturbed fragments may indicate the species' minimum requirements and might contribute to their conservation. Here we show how the mammalian fauna of medium and large size (higher than 1 kg) are structured in a semideciduous seasonal forest fragment of 36.5 ha in the urban area of Jataí, Goiás. We performed the sampling with 30 sand track plots (1 x 1 m). We analyzed the relative record frequency and built a collector's curve to demonstrate the sampling effort. With a total effort of 600 track plots × days, we recorded twelve species of mammals with our tracks sampling method, from which only the wild mammals were included in the analyzes (11 species). The estimated species richness reached 13 species (SD (Standard Deviation) = ±1, CI (Confidence Interval) = ±2 (11 – 15 species). The species with the highest relative record frequency was Didelphis albiventris and the species with the lowest was Tamandua tetradactyla. The fragment size must be a limiting factor to the richness and to the occurrence of species, as it may not be sufficient to allow the persistence of a population or an individual. Disturbances that originated from houses, like domestic animals and movement of people, also contributed to the removal and extinction of species. To conserve the species in the fragment, we suggest the prevention of entrance of people and of domestic animals. We also recommend increased connectivity of the fragment with the landscape external to the urban area in order to allow the movement of the currently present species.

Mesopredator release within an oceanic island

Rayner, M. J., Hauber, M. E., Imber, M. J., Stamp, R. K., & Clout, M. N. (2007). Spatial heterogeneity of mesopredator release within an oceanic island system. Proceedings of the National Academy of Sciences, 104(52), 20862-20865.

Predator–prey communities are ubiquitous in ecology, but introduced predators can drive native species to extinction within island systems, prompting the eradication of such exotics. Ecological theory predicts that elimination of top-introduced predators from islands can lead to the counterintuitive decline of native prey populations through the ecological release of smaller introduced species in a process termed “mesopredator release”.

 We show, in accordance with mesopredator release theory and counter to conservation goals for a New Zealand island reserve, that initial eradication of cats on Little Barrier Island led to reduced breeding success of Cook's petrels, which also are vulnerable to predation by a mesopredator, the Pacific rat. The rat's impact on prey productivity varied with elevation within the island. Rat eradication was followed by a rise in petrel productivity, in support of both ecological theory and practical conservation management goals. It appears that interactions among introduced predators, native prey, and environmental gradients can drive counterintuitive and spatially heterogeneous responses to predator eradications from islands. Location-specific, ecosystem-level understanding is essential for predicting the outcomes of such restoration management techniques.


Related articles

Dog outcompete vultures at sea lion colony

Pavés, H. J., Schlatter, R. P., & Espinoza, C. I. (2008). Scavenging and predation by Black Vultures Coragyps atratus at a South American sea lion breeding colony. Vulture News, 58(1), 4-15.

Many animal species benefit from resources provided by other species. Such species may develop or coevolve particular interspecific relationships (for example: competition, depredation and mutualism). During two sea lion breeding seasons (1996-97 and 1997- 98), we observed behavioral interactions at the Punta Lobería Southern Sea-lion Otaria flavescens colony. We documented facultative mutualism, commensalism and depredation by Black Vulture Coragyps atratus, Kelp Gull Larus dominicanus and Domestic Dogs Canis familiaris on sea lions. Competitive relationships between Black Vulture and dogs were observed. We recorded depredatory behaviour by vultures on live seal pups. Black Vultures were the dominant bird consumer on carcasses in the absence of feral dogs. Sea lion mother displayed agonistically when Black Vultures approached their pups. Vultures fed on sea lion placentas and umbilical cords during the birth period. 12-17% of the sea lion pups suffered attacks by Black Vultures during our two season's observations. Dogs compete advantageously with vultures on seal pup carcasses. We postulate that the shift
from mutualistic scavenging to depredation by vultures may be influenced by hunger stress due to competition with feral dogs for limited sea lion carrion.


Distintas especies de animales se asocian y benefician de los recursos generados en una colonia reproductiva de lobo marino común (Otaria flavescens), desarrollando un conjunto de relaciones interespecíficas coevolutivas particulares (competencia, depredación, mutualismo, entre otros). Durante dos periodos reproductivos (1996-1997 y 1997-1998) se realizaron observaciones de las conductas interespecíficas en la colonia reproductiva de Punta Lobería (38º39'S; 73º29'W). Se registraron relaciones de tipo mutualista, comensal y depredadoras, entre Jote cabeza negra (Coragyps atratus), Gaviota dominicana (Larus dominicanus) y Perros domésticos abandonados (Canis familiaris) sobre O. flavescens. Relaciones competitivas entre Jote cabeza negra, Jote de cabeza colorada (Cathartes aura), Gaviotas dominicanas y perros domésticos fueron también identificadas. Los Jotes en ausencia de perros vagos tienden a ser los carroñeros dominantes en este tipo de gremio. Las madres de los cachorros de lobo marino común despliegan conductas agonísticas ante la aproximación de jotes quienes se alimentan de las placentas y cordones umbilicales expulsados durante el parto. Se registraron conductas de tipo depredadora de jotes sobre cachorros vivos de lobo marino común. Entre un 12% y 17% de los cachorros sufrieron ataques por jotes durante ambas temporadas. Los perros vagos compiten en forma ventajosa con jotes por carroña. Se postula que la redirección de una conducta carroñera mutualista a depredadora, en el jote de cabeza negra, estaría influenciada por estrés alimentario, bajo el efecto competitivo dominante con perros vagos por cadáveres de lobos marinos.

Diet and home range of feral cats in Galápagos

Konecny, M. J. (1987). Home range and activity patterns of feral house cats in the Galapagos Islands. Oikos, 50: 17-23.

The spatial organization of two populations of feral house cats Felis catus, was examined in the Galápagos Islands using mark-recapture and radio telemetry. Both populations were located in the same habitat vegetation type and had approximately equal densities of cats. Two sites differing in resource density and habitat heterogeneity also differed significantly in home range size and amount of overlap. Male home ranges averaged 3.04 km² while those of females averaged 0.82 km². Monthly home ranges did not vary significantly. Activity patterns were roughly bimodal with peaks near dawn and dusk and lows near midday. Daily movement paths differed between sites. Resource levels and home range patterns suggest a resource threshold territoriality based on resource depression at the poorer site while no territoriality was found at the richer site demonstrating the adaptability and ecological flexibility of feral cats.

Konecny, M. J. (1987). Food habits and energetics of feral house cats in the Galápagos Islands. Oikos, 50: 24-32.

The food habits of feral cats (Felis catus) were assessed by visual observations and scats collected in two seasons and at two sites in the Galápagos Islands. Cats were seen to both scavenge and attack live prey with a capture efficiency of 32%. In seasonal comparisons significantly more food items were included in the dry season (7.4) than the wet (5.7). Significantly more items were included in the diet at Tagus Cove (7.8) which was less productive than Cerro Colorado (6.7). The diet included both vertebrate and invertebrate prey but vertebrates constituted 71.9% of each scat by weight and 93.4% of the energy. The estimated daily intake of energy was 170 kcal which is at the caloric break even point for non-pregnant females, slightly below that for adult males and pregnant females and well below that for lactating females. The food habit and energetic data were combined to make some predictions about food preferences, foraging decisions and the role of available water on feral cats.

Dog predation on marine iguanas

Kruuk, H., & Snell, H. (1981). Prey selection by feral dogs from a population of marine iguanas (Amblyrhynchus cristatus). Journal of Applied Ecology, 18: 197-204.

(1) Factors are examined which influence prey selection by feral dogs from a population of marine iguanas on Isabela, Galápagos, Ecuador.

(2) For various size classes of iguanas the relative risk of predation by dogs is significantly greater for large animals. 

(3) Variation in risk was related to differential fleeing distances, and to the greater exposure of territorial male iguanas which did not seek shelter at night. 

(4) Anti-predator behaviour of iguanas did not protect them against feral dogs, and dog predation was probably considerably greater than the marine iguana population could sustain.

Introgression of domestic dog haplotype in coyote

Adams, J. R., Leonard, J. A., & Waits, L. P. (2003). Widespread occurrence of a domestic dog mitochondrial DNA haplotype in southeastern US coyotes.Molecular Ecology, 12(2), 541-546.

Sequence analysis of the mitochondrial DNA control region from 112 southeastern US coyotes (Canis latrans) revealed 12 individuals with a haplotype closely related to those in domestic dogs. Phylogenetic analyses grouped this new haplotype in the dog/grey wolf (Canis familiaris/Canis lupus) clade with 98% bootstrap support. These results demonstrate that a male coyote hybridized with a female dog, and female hybrid offspring successfully integrated into the coyote population. The widespread distribution of this haplotype from Florida to West Virginia suggests that the hybridization event occurred long ago before the southeastern USA was colonized by coyotes. However, it could have occurred in the southeastern USA before the main front of coyotes arrived in the area between male coyotes released for sport and a local domestic dog. The introgression of domestic dog genes into the southeastern coyote population does not appear to have substantially affected the coyote's genetic, morphological, or behavioural integrity. However, our results suggest that, contrary to previous reports, hybridization can occur between domestic and wild canids, even when the latter is relatively abundant. Therefore, hybridization may be a greater threat to the persistence of wild canid populations than previously thought.

See more about wild canid hybridisation with dogs

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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Hyperpredation: Cat diet on a small Mediterranean island

Bonnaud, E., Bourgeois, K., Vidal, E., Kayser, Y., Tranchant, Y., & Legrand, J. (2007). Feeding ecology of a feral cat population on a small Mediterranean island. Journal of Mammalogy, 88(4), 1074-1081.

Domestic cats (Felis catus) have been introduced on many islands in the world and are responsible for much damage to native insular faunas. The worldwide success and spread of this opportunistic predator is generally associated with its trophic adaptability. We examined the diet of a long-established feral cat population on a small Mediterranean island through the analysis of 1,219 scats collected during a 4-year period. Our results confirm that feral cats are generalist predators, able to feed on a wide range of prey. However, only a few prey species formed the major part of its diet. Two introduced mammals and a Mediterranean endemic seabird provided 93% of the yearly biomass consumed by cats (ship rats, 70%; wild rabbits, 7%; and yelkouan shearwaters, 6%). Ship rats remained by far the staple prey for cats throughout the year, but the diet of feral cats was more diversified in spring and early summer, frequently including insects, reptiles, and migrant birds. Endemic yelkouan shearwaters were preyed upon most frequently in autumn and winter, that is, during the shearwaters' prelaying period. Because rats provide the majority of the food of cats, they could help to maintain or inflate this alien predator population with deleterious consequences to the endemic shearwater. A cat eradication campaign would help protect the population of shearwaters on this island.

Diet of feral cats on farmland in New Zealand

Langham, N. P. E. (1990). The diet of feral cats (Felis catus L.) on Hawke’s Bay farmland, New Zealand. New Zealand journal of zoology, 17(2), 243-255.

Food remains were analysed in 361 cat faeces (scats) collected from September 1983 to May 1987 on farmland in southern Hawke’s Bay. Mammals were the most important food items in scats, both by occurrence (76%) and by weight (74%). House mice were the most frequently (50%) encountered remains, and comprised only 12% of the total prey identified by weight; rats were less frequently found (20%) but the most important item by weight (39%). Other mammals found were scavenged possums (13% by weight), sheep (7%), and lagomorphs (3%). Birds, consisting mainly of introduced species, including turkeys, were both frequent (24%) and important by weight (24%). Invertebrate remains consisted mainly of cicada nymphs (Homoptera) (10% by frequency), grass grubs (Coleoptera) (8%), and black field crickets (Orthoptera) (7%) contributed less than 2% by weight. Cicada nymphs were recorded only in willow/ swamp habitat. No significant differences were found between vertebrate prey recorded in scats from willows and swamps and vertebrate prey from bams and pasture. There were no consistent local or seasonal changes in frequency of occurrence of rats, but mice were found more frequently in scats collected in winter. Possum remains were found mainly in winter. Birds were the main items in scats collected in the spring and summer months. Eggs of Toxocari cati (64%) were the only identifiable internal parasite frequently found in the scats.

Precautionary principle applied to predation by pet cats

Calver, M. C., Grayson, J., Lilith, M., & Dickman, C. R. (2011). Applying the precautionary principle to the issue of impacts by pet cats on urban wildlife.Biological Conservation, 144(6), 1895-1901.

Despite evidence that pet cats prey on urban wildlife and may transmit disease, there is uncertainty over whether they cause declines in wildlife populations. The uncertainty fosters disagreement about whether and how pet cats should be managed, and hampers the implementation of regulations. We suggest that the precautionary principle could be used in this context. The principle mandates action to protect the environment when there is a scientifically plausible but unproven risk, and provides a rationale for immediate intervention to protect wildlife from pet cats while we await definitive studies. In applying a 4-step guide for implementing the precautionary principle, we argue that: (i) current data documenting wildlife mortality caused by pet cats satisfy the precautionary trigger of scientifically plausible risk; (ii) the risk of significant declines or local extinctions of threatened wildlife, coupled with uncertainty in establishing population declines in response to pet cats, argue for strong levels of precaution; (iii) precautionary measures that should be considered include, but are not limited to, restrictions on the maximum number of cats allowed/household, mandatory sterilisation and registration of pet cats, curfews, requiring pet cats roaming outdoors to wear collar-mounted predation-deterrents or compulsory confinement of cats to their owners’ premises; and (iv) the principle’s requirement for extensive consultation in implementing precautionary measures should encourage collaborations involving conservation biologists, veterinarians, animal welfare activists, concerned citizens and municipal officers. Adherence to these steps should assist in choosing actions that have broad support and are applicable to unique local circumstances.


Highlights

► The precautionary principle justifies protecting wildlife from pet cats. ► Deaths caused by pet cats show scientifically plausible risk of population declines. ► Risk, plus uncertainty of wildlife decline from cat predation, support precaution. ► Specialists and the community must collaborate to implement precaution. ► Implementation should follow adaptive management principles to reduce uncertainty.

Regulation of cat ownership based on precautionary principle

Grayson, J. and Calver, M.C. (2004) Regulation of domestic cat ownership to protect urban wildlife: a justification based on the precautionary principle. In: Lunney, D. and Burgin, S., (eds.) Urban wildlife: more than meets the eye. Royal Zoological Society of New South Wales, Mosman, pp. 169-178.

While it is undeniable that both feral cats and owned domestic cats prey on native wildlife, evidence that this is a threat to the viability of wildlife populations is contentious, particularly in the suburbs. Where uncertainty is great or the risks are high, the precautionary principle is a guide as to whether or not action should be taken to regulate domestic cats This involves an evaluation of the available evidence and the extent of uncertainty, as well as consideration of the viewpoints of major stakeholders. Applying this approach leads to the conclusion that wildlife can be protected while improving cat welfare, Containing cats at night not only separates cats and nocturnal wildlife, but minimises trauma from both cat fights and road accidents while reducing nuisance to neighbours from caterwauling and fighting. Desexed cats no longer contribute toward unwanted stray and feral cat populations that depredate native wildlife populations and are often less of a nuisance to neighbours and themselves as spraying and fighting are reduced. Cats with identification can be returned to their owners should they be found lost or injured, while problem cats can be identified. Therefore, the cat welfare issue is the key to a successful precautionary approach because it achieves wildlife protection while respecting the interests of cat owners.

Bird and rat numbers on Little Barrier after cat eradication

Girardet, S. A. B., Veitch, C. R., & Craig, J. L. (2001). Bird and rat numbers on Little Barrier Island, New Zealand, over the period of cat eradication 1976–80. New Zealand Journal of Zoology, 28(1), 13-29.

Passerines were monitored on Little Barrier Island over 15 years (1975–89) spanning the period (1976–80) when feral cats were eradicated from the island. All birds seen and heard were recorded while walking three transects representing an altitudinal range from near sea level to approximately 550 m above sea level. Analysis of variance statistics were used to test for differences in bird numbers between transects and between years. Bird species were examined by transect to test for changes in numbers over time. Three species had increased on some transects, and two species had decreased on some transects, but it was difficult to attribute changes in bird numbers to the one cause which we were able to study: reduced cat numbers. Examination of numbers of individuals of 14 species recorded between transects showed significant differences for some individual species, but not for all species grouped together. Four species did not show any significant differences between transects. This study demonstrates different patterns in bird distributions on Little Barrier Island which cannot be understood from these data.

Index traplines were set for Pacific rats or kiore (Rattus exulans) between 1977 and 1984, before and after cat eradication. Rat numbers fluctuated widely, and there were no significant differences that could be attributed to the changes in cat numbers.

Related articles

Eradication of cats on Little Barrier

Veitch, C. R. (2001). The eradication of feral cats (Felis catus) from Little Barrier Island, New Zealand. New Zealand Journal of Zoology, 28(1), 1-12.

Feral cats (Felis catus) probably reached Little Barrier Island in about 1870. They contributed to the total extinction of the Little Barrier snipe (Coenocorypha aucklandica barrierensis), the local extinction of North Island saddleback (Philesturnus carunculatus rufusater) and the severe reduction in numbers of grey‐faced petrel (Pterodroma macroptera gouldi), Cook's petrel (P. cookii) and black petrel (Procellaria parkinsoni), plus the decline of lizard and tuatara species.

Sporadic cat control was carried out on Little Barrier from 1897 to 1977. A determined eradication attempt commenced in July 1977 was completed on 23 June 1980. Cage traps, leg‐hold traps, dogs and 1080 poison were used, but leg‐hold traps and 1080 poison were the only effective methods. Altogether, 151 cats were known to have been killed before the eradication was declared complete. Important lessons learnt can be transferred to other feral cat eradication programmes. The responses of the bird populations are described elsewhere (Girardet et. al. 2001).

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Alien carnivores' diet in New South Wales

Meeks, P.D. & B. Triggs. 1998. The food of foxes, dogs and cats on two peninsulas in Jervis Bay, New South Wales. Proceedings of The Linnean Society of New South Wales 120: 117-127

European Red Fox Vulpes vulpes (L.), Dog Canis lupus familiaris/dingo (L.), and Cat Felis catus (L.) scats were analysed to assess the food, and report on the diet of these predators from two peninsulas at Jervis Bay, NSW. The main food items of V. vulpes comprise mammal, Pseudocheirus peregrinus (26.8%) on Bherwerre Peninsula, and Rattus rattus (37.9%) on Beecroft Peninsula. Invertebrates, vegetation and birds were also important food items of V. vulpes on both peninsulas. The diet of C. lupus familiaris consisted mainly of Wallabia bicolor on both peninsulas, while P. peregrinus, Oryctolagus cuniculus and R. rattus were also eaten. F. catus favoured mammals over invertebrates, birds and vegetation. An important finding from the survey was the occurrence of four locally endangered species; Pseudomys gracilicaudatus, Sminthopsis leucopus and Litoria aurea on Bherwerre Peninsula and Rattus lutreolus on Beecroft Peninsula. Differences in predator food preferences between Beecroft and Bherwerre reflect the differences in prey diversity on each peninsula, and supports the theory that V. vulpes and F. catus are opportunistic feeders that select the most abundant food items. In contrast C. lupus familiaris were more selective and favoured medium to large macropods.

Home range of feral cats as introduced apex predators in insular ecosystems

Recio, M. R., & Seddon, P. J. (2013). Understanding determinants of home range behaviour of feral cats as introduced apex predators in insular ecosystems: a spatial approach. Behavioral Ecology and Sociobiology, 1-11.

The introduced feral cat (Felis catus) is a widespread generalist with flexible social behaviour and an apex predator without major interspecific competitors in insular ecosystems that evolved in the absence of predators. Mechanistic definitions consider an animal’s home range to be the spatial expression of a cognitive map that is kept up-to-date with the status of critical resources that contribute to animal fitness. We assumed there are two major determinants structuring the home range of cats as apex predators in insular ecosystems: the distribution of critical food resources and conspecific distribution. We hypothesized that cats structure their home ranges by optimizing the use of staple critical food resources and that as a consequence of the presence of rich resources cats tend to socialise, aggregate and share space. We carried out spatial analyses using location data for feral cats tracked using lightweight GPS collars in conjunction with the suitability value of rabbit patches and their associated ownership costs for cats within a New Zealand braided-river environment. Cat home ranges and spatial distribution, especially for females, were related to the inclusion of rabbit patches within home ranges with higher mean value than the average of neighbourhood patches in the landscape. Cats showed solitary behaviour but tolerance to conspecific presence by sharing high-use areas and high-value rabbit patches, mostly at different times, resulting in occasional encounters among males and females. Home range size and patterns of spatial overlap were dependant on sex and season. Solitary spacing patterns as consequence of innate preferences together with resource constraints may regulate feral cat population densities.

Roaming, stray, and feral domestic cats and dogs as wildlife problems

Van't Woudt, B. D. (1990). Roaming, stray, and feral domestic cats and dogs as wildlife problems. Proceedings of the Fourteenth Vertebrate Pest Conference 1990, Sacramento, California

From several centers of domestication, cats and dogs have become the near-ubiquitous companion of man. Their dependence on man is such that when abandoned in a rural environment most succumb to malnutrition in combination with predation, diseases, parasites, and exposure. Where not subject to predation and where native or introduced prey is adequate, some survive to form feral populations. This applies on oceanic islands, in Australia and New Zealand. Elsewhere, as far as is known today, requirements for survival are met with in parts of the U.S. and Europe only, in remote wilderness areas in the case of dogs, and more widespread, with a tendency to fall back on surplus and waste products of man during hard times in the wild, in the case of cats. Where vermin populations, such as those of rabbits, rats and mice are dense, cats provide inadequate control; they can be useful in keeping small vermin populations small. Away from oceanic islands and desert areas, where their impact on native animals can be disastrous, this makes them sufficiently useful for damage to wildlife (notably to lizards, small marsupials and some birds) to be outweighed, without providing a clear-cut case for a need for control of either roaming, stray or feral cats in rural areas. On the other hand, dogs are potentially destructive animals, whether roaming, stray, or feral; they demand strict control

TNR vs. TVHR to control feral cats

McCarthy, R. J., Levine, S. H., & Reed, J. M. (2013). Estimation of effectiveness of three methods of feral cat population control by use of a simulation model. Journal of the American Veterinary Medical Association,243(4), 502-511.

Objective—To predict effectiveness of 3 interventional methods of population control for feral cat colonies.

Design—Population model.

Sample—Estimates of vital data for feral cats.

Procedures—Data were gathered from the literature regarding the demography and mating behavior of feral cats. An individual-based stochastic simulation model was developed to evaluate the effectiveness of trap-neuter-release (TNR), lethal control, and trap-vasectomy-hysterectomy-release (TVHR) in decreasing the size of feral cat populations.

Results—TVHR outperformed both TNR and lethal control at all annual capture probabilities between 10% and 90%. Unless > 57% of cats were captured and neutered annually by TNR or removed by lethal control, there was minimal effect on population size. In contrast, with an annual capture rate of ≥ 35%, TVHR caused population size to decrease. An annual capture rate of 57% eliminated the modeled population in 4,000 days by use of TVHR, whereas > 82% was required for both TNR and lethal control. When the effect of fraction of adult cats neutered on kitten and young juvenile survival rate was included in the analysis, TNR performed progressively worse and could be counterproductive, such that population size increased, compared with no intervention at all.

Conclusions and Clinical Relevance—TVHR should be preferred over TNR for management of feral cats if decrease in population size is the goal. This model allowed for many factors related to the trapping program and cats to be varied and should be useful for determining the financial and person-effort commitments required to have a desired effect on a given feral cat population.



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Habitat structure mediates the non-lethal effects of mesopredation

Arthur, A. D., Pech, R. P., & Dickman, C. R. (2004). Habitat structure mediates the non‐lethal effects of predation on enclosed populations of house mice. Journal of Animal Ecology, 73(5), 867-877.

1 Prey behavioural changes in response to predation risk can result in significant effects on prey body growth rates and reduced reproductive output, with resultant impacts on prey population dynamics. This paper examines the influence of habitat structure on these non-lethal impacts of predation using a model, field-based experimental system, with house mice as prey.
2 Three treatments were employed in eight 50 × 50 m pens that contained mice, but allowed access to a suite of free-living vertebrate predators, which included feral foxes, feral cats and native raptors: a treatment where the natural grassland vegetation in the pens was maintained at a height < 10 cm; a treatment where small, felled cypress pine trees covered with wire netting were added to low grassland vegetation to create refuge areas covering 10–15% of the area in a pen; and a treatment where predators were excluded from a 25 × 25 m section of some pens with an underlying grassland structure. A 5 × 5 grid of felled trees was added to grassland and predator-exclusion pens to allow assessment of mouse behaviour.
3 Mice in grassland pens avoided open areas, had lower body growth rates, and began breeding later in spring than mice in both predator-exclusion areas, where they foraged more readily in the open, and in refuge pens, where mice avoided open areas but had safe access to supplementary food located within the refuge. These results occurred despite mouse population densities being much lower in grassland pens, and presumably competition for food being much less, compared with under the other treatments.
4 The results indicate predators can have significant non-lethal impacts on prey, and these effects can be mediated by habitat structure.

Ecology of feral cats in open forest in Australia

MOLSHER, R. L. (2006). The ecology of feral cats, Felis catus, in open forest in New South Wales: interactions with food resources and foxes. Australian Nature Conservation Agency

This report provides an overview of the impact of feral cats Felis catus on native fauna of the Pacific region, with particular reference to Australia and its island territories. In Australia, cats take a wide variety of native species of mammals, birds and reptiles, but show evident preference for young rabbits or small marsupials where these are available. Reptiles are taken primarily in and habitats, while birds often feature predominantly in the diet of cats on islands. Despite their catholic diet, population-level impacts of feral cats on native fauna have been poorly documented. There is considerable potential for competition to occur between cats and carnivorous species such as quolls and raptors, but no critical evidence has yet been adduced. There is also potential for amerisal impacts to occur, either via transmission of the pseudophyllidean tapeworm Spirometra erinacei or of the protozoan parasite Toxoplasma gondii, but evidence for deleterious effects in freeliving animals is not compelling. Direct predatory impacts have been inferred from anecdotal and historical evidence, more strongly from failed attempts to reintroduce native species to their former ranges, and most critically from the decimation of island faunas and responses of prey species following experimental removal of cats or reduction of cat numbers. Attributes of the biology of feral cats and their prey species derived from the literature review were used to develop a rank-scoring system to assess the susceptibility of native species to cat predation. Species listed federally as endangered or vulnerable were designated as being at zero, low or high risk of impact from cats according to their attribute scores, and their distributions mapped from primary sources and actual locality data. Based on the number of threatened species they contain, localities and regions within Australia were placed in order of priority for future research to clarify the precise impacts of feral cats. Although difficult and expensive to carry out, controlled and replicated field removal experiments are recommended to elucidate cat impacts in all mainland areas. Removal of cats should take place also on offshore islands and island territories, but only if pilot studies show that this will not release populations of alternative predator species such as introduced rats. If release appears likely, cats should be removed only as a component of an integrated control program that targets all relevant predators.

Impact of exotic generalist predators on the native fauna of Australia

Dickman, C. R. (1996). Impact of exotic generalist predators on the native fauna of Australia. Wildlife Biology, 2(3), 185-195.

This paper reviews the impacts of three species of introduced mammalian predators on native fauna in Australia. The feral cat Felis catus, introduced over 200 years ago, is linked with early continental extinctions of up to seven species of mammals, regional and insular extinctions of many more species of mammals and birds, and the failure of management programs attempting to reintroduce threatened native species to parts of their former ranges. Evidence for cat-impact is largely historical and circumstantial, but supported by observations that afflicted native species are, or were, small (<200 g) occupants of open habitat and hence likely to be especially vulnerable to cat predation. The red fox Vulpes vulpes was released successfully in 1871. Its subsequent spread into all except parts of arid and tropical Australia coincided with local and regional declines of medium-sized (450-5,000 g) mammals, birds and chelid tortoises. The fox has also created recent failures of many management attempts to recover threatened native species. Unequivocal demonstration of fox-impact has been obtained in removal experiments, especially on rock-wallabies Petrogale lateralis. The dingo Canis lupus dingo, introduced 3,500-4,000 years ago, probably caused the extinction of the thylacine Thylacinus cynocephalus and Tasmanian devil Sarcophilus harrisii on mainland Australia. It effectively suppresses extant populations of large mammals, such as kangaroos, and emus, over large areas. Impacts of all three predators are wrought primarily by direct predation. Negative impacts appear to be increased in spatially fragmented forests where native species are restricted to remnant vegetation, and in arid landscapes when native species become restricted temporarily to scattered oases during drought. Alternative prey, especially rabbits Oryctolagus cuniculus, enhance negative impacts on native species by supporting large populations of the predators. It is concluded that feral cats and especially foxes have major negative impacts on certain small and medium-sized native vertebrates in Australia, whereas dingoes have major negative impacts on large species. Dingoes could have positive effects on smaller native species if they significantly suppress populations of foxes and cats. Further quantification of both the direct and indirect impacts of the three predators on native fauna is needed, and should be obtained from experimental field studies.

Exotic mammals structure Australian biota

Davey, C., A. R. E. Sinclair, R. P. Pech, A. D. Arthur, C. J. Krebs, A. E. Newsome, D. Hik, R. Molsher, & K. Allcock (2006). Do exotic vertebrates structure the biota of Australia? An experimental test in New South Wales. Ecosystems,9(6), 992-1008

From 1993 to 2001, we conducted a series of experiments in a mixed grassland–woodland system in central New South Wales (NSW) to quantify the interactions between red foxes and their prey and competitors. Foxes were removed from two areas around the perimeter of Lake Burrendong, and data were collected from these areas and a nearby untreated area before, during, and after the period of fox control. The arrival of rabbit hemorrhagic disease (RHD) in 1996 provided an opportunity to examine the interactive effects of controlling foxes and rabbits. In this landscape, typical of central NSW, (a) the fox population was not affected by a large reduction in the abundance of rabbits, or vice versa; (b) the cat population declined in areas where foxes were removed after the large RHD-induced reduction in rabbit numbers, but there was no consistent response to the removal of foxes; (c) the abundance of some macropod species increased in response only to the combined removal of rabbits and foxes; (d) there were no consistent changes in the abundances of bird species in response to the removal of either foxes or rabbits, but there were clear habitat differences in bird species richness; and (e) there was likely to be an increase in woody plant species after the large reduction in rabbit populations by RHD. We conclude that (a) long-term field experiments (more than 3 years) are required to quantify the indirect consequences of controlling foxes and rabbits, and (b) single manipulations, such as fox control or rabbit control, are not necessarily sufficient for the conservation of remnant woodland communities in southeastern Australia.

Antipredator strategies of house finches in towns

Valcarcel, A., & Fernández-Juricic, E. (2009). Antipredator strategies of house finches: are urban habitats safe spots from predators even when humans are around?. Behavioral Ecology and Sociobiology, 63(5), 673-685.

Urbanization decreases species diversity, but it increases the abundance of certain species with high tolerance to human activities. The safe-habitat hypothesis explains this pattern through a decrease in the abundance of native predators, which reduces predation risk in urban habitats. However, this hypothesis does not consider the potential negative effects of human-associated disturbance (e.g., pedestrians, dogs, cats). Our goal was to assess the degree of perceived predation risk in house finches (Carpodacus mexicanus) through field studies and semi-natural experiments in areas with different levels of urbanization using multiple indicators of risk (flock size, flight initiation distance, vigilance, and foraging behavior). Field studies showed that house finches in more urbanized habitats had a greater tendency to flock with an increase in population density and flushed at larger distances than in less urbanized habitats. In the semi-natural experiment, we found that individuals spent a greater proportion of time in the refuge patch and increased the instantaneous pecking rate in the more urbanized habitat with pedestrians probably to compensate for the lower amount of foraging time. Vigilance parameters were influenced in different ways depending on habitat type and distance to flock mates. Our results suggest that house finches may perceive highly urbanized habitats as more dangerous, despite the lower number of native predators. This could be due to the presence of human activities, which could increase risk or modify the ability to detect predators. House finches seem to adapt to the urban environment through different behavioral strategies that minimize risk.

Cats favoured by habitat fragmentation and isolation

Crooks, K.R. 2002. Relative sensitivities of mammalian carnivores to habitat fragmentation. Conservation Biology 16(2): 488-502.

I examined the effects of habitat fragmentation on the distribution and abundance of mammalian carnivores in coastal southern California and tested the prediction that responses to fragmentation varied with the body size of carnivore species. I conducted track surveys for nine native and two exotic carnivore species in 29 urban habitat fragments and 10 control sites. Fragment area and isolation were the two strongest landscape descriptors of predator distribution and abundance. Six species were sensitive to fragmentation, generally disappearing as habitat patches became smaller and more isolated; three species were enhanced by fragmentation, with increased abundance in highly fragmented sites; and two species were tolerant of fragmentation, with little to no effect of landscape variables on their distribution and abundance. Within urban habitat fragments, the carnivore visitation rate increased at sites with more exotic cover and closer to the urban edge, a pattern driven largely by the increased abundance of fragmentation-enhanced carnivores at edge sites. Finally, body size, in conjunction with other ecological characteristics, partially accounted for the heterogeneity in responses to fragmentation among carnivore species. These differential sensitivities are useful criteria for choosing appropriate focal species for ecological research and conservation planning, a choice that depends on the scale of fragmentation in a region and the commensurate responses of carnivore populations at that scale.

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Examiné los efectos de la fragmentación del hábitat sobre la distribución y abundancia de mamíferos carnívoros en la costa del sur de California y evalué la predicción de que las respuestas a la fragmentación variaban con el tamaño corporal de carnívoros. Se realizaron muestreos de huellas para nueve especies nativas y dos exóticas en 29 fragmentos de hábitat urbano y 10 sitios control. El área fragmentada y su aislamiento fueron los dos principales descriptores de la distribución y abundancia de depredadores. Seis especies fueron sensibles a la fragmentación, generalmente las especies desaparecían conforme los fragmentos eran más pequeños y aislados, tres especies fueron favorecidas por la fragmentación, con incremento en su abundancia en sitios altamente fragmentados, y dos especies fueron tolerantes a la fragmentación con poco o ningún efecto de las variables del paisaje sobre su distribución y abundancia. Dentro de los fragmentos de hábitat urbano, las tasas de presencia de carnívoros incrementaron en sitios con mayor cobertura exótica y cercanos al borde urbano, un patrón dirigido principalmente por el incremento en la abundancia de carnívoros favorecidos por la fragmentación en el borde de los sitios. Finalmente, el tamaño corporal, conjuntamente con otras características ecológicas, fueron parcialmente responsables de la heterogeneidad en respuestas a la fragmentación entre especies de carnívoros. Estas sensibilidades diferenciales son un criterio útil para seleccionar especies focales apropiadas para investigaciones ecológicas y la planeación de la conservación, una selección que depende de la escala de fragmentación en una región y de las respuestas apropiadas de las poblaciones de carnívoros a esa escala.

Rabies risk to Ethiopian wolf

Haydon, D. T., Laurenson, M. K., & Sillero‐Zubiri, C. (2002). Integrating epidemiology into population viability analysis: managing the risk posed by rabies and canine distemper to the Ethiopian wolf. Conservation Biology, 16(5), 1372-1385.

Infectious disease constitutes a substantial threat to the viability of endangered species. Population viability analysis (PVA) can be a useful tool for directing conservation management when decisions must be made and information is absent or incomplete. Incorporating epidemiological dynamics explicitly into a PVA framework is technically challenging, but here we make a first attempt to integrate formal stochastic models of the combined dynamics of rabies and canine distemper into a PVA of the Ethiopian wolf ( Canis simensis), a critically endangered canid. In the absence of disease, populations in habitat patches of every size were remarkably stable and persistent. When rabies virus was introduced, epidemics, assumed to arise from sporadic dog-to-wolf transmission, caused extinction probabilities over 50 years to rise linearly with the force of infection from the dog reservoir and particularly steeply in smaller populations. Sensitivity analysis revealed that although the overall pattern of results was not altered fundamentally by small to moderate changes in disease-transmission rates or the way in which interpack disease transmission was modeled, results were sensitive to the process of female recruitment to male-only packs. Completely protecting wolf populations from rabies through vaccination is likely to be impractical, but the model suggested that direct vaccination of as few as 20–40% of wolves against rabies might be sufficient to eliminate the largest epidemics and therefore protect populations from the very low densities that make recovery unlikely. Additional simulations suggested that the affect of periodic epidemics of canine distemper virus on wolf population persistence was likely to be slight, even when modeled together with rabies. From a management perspective, our results suggest that conservation action to protect even the smallest populations of Ethiopian wolves from rabies is both worthwhile and urgent.

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Las enfermedades infecciosas constituyen una amenaza sustancial contra la viabilidad de las especies en peligro. El análisis de viabilidad poblacional ( PVA) puede ser una herramienta útil para dirigir la conservación para el manejo cuando las decisiones deben ser tomadas y la información es escasa o incompleta. La incorporación de dinámicas epidemiológicas explícitamente dentro de una marco PVA es técnicamente un reto; sin embargo, llevamos a cabo el primer intento para integrar modelos estocásticos formales de la dinámica de la rabia y del moquillo canino para un PVA del lobo etíope (Canis simensis), un cánido críticamente amenazado. En ausencia de la enfermedad, las poblaciones que habitan parches de hábitat de todos los tamaños fueron llamativamente estables y persistentes. Cuando se introduce el virus de la rabia, las epidemias, que supuestamente surgen de transmisiones esporádicas de perro a lobo, hicieron que las probabilidades de extinción sobre 50 años se incrementaran linealmente con la fuerza de la infección del perro reservorio y particularmente de manera abrupta en poblaciones pequeñas. El análisis de sensibilidad reveló que a pesar de que el patrón general de los resultados no haya sido alterado fundamentalmente por cambios pequeños o moderados en las tasas de transmisión de la enfermedad ni por la forma en que la transmisión de la enfermedad al interior del grupo fue modelada, los resultados fueron sensibles al proceso de reclutamiento de hembras en grupos de machos. La protección total de las poblaciones de lobos mediante vacunación contra la rabia probablemente no es práctica, pero el modelo sugiere que la vacunación directa de por lo menos un 20-40% de los lobos podría ser suficiente para eliminar las epidemias más grandes y por lo tanto proteger poblaciones con densidades muy bajas que harían poco probable una recuperación. Posteriores simulaciones sugirieron que las repercusiones sobre epidemias de moquillo canino en la persistencia de poblaciones de lobos serían probablemente ligeras, aún cuando se modelaran conjuntamente con la rabia. Desde la perspectiva del manejo, nuestros resultados sugieren que las acciones de conservación para proteger aún a las poblaciones más pequeñas de lobos etíopes de la rabia son importantes y urgentes.

Two studies on Dog Population in Makurdi, Nigeria

Omudu, E. A., Otache, E. O., & Adelusi, S. M. (2010). Studies on Dog Population in Makurdi, Nigeria (I): Demography and Survey of Pet Owners' Beliefs and Attitudes. Journal of Research in Forestry, Wildlife and Environment, 2(1), 85-93.

A survey of dog population in some residential areas of Makurdi, Nigeria, was investigated using household census and street observation methods, while residents' dog-related attitudes and beliefs were investigated using a structured questionnaire. The average number of dogs per household was 1.43. Dog-human ratio in the study location was 1 dog to every 4 persons, in Wurukum residential area this was however less with the ratio of 1 dog to every 3 persons. There was no significant (X² = 1.42, df = 1, P > 0.05) difference in the distribution of sexes of dogs. The difference between free roaming dogs and those restricted within residential compounds was also not statistically significant (X² = 1.08, P > 0.05). A total of 198 (98.0%) respondents who owned dogs kept them as house guards and/or security alert; only 18.8% of dog owners kept them as pets. The variation in reasons for keeping dogs was significant (X2 = 12.1, P < 0.05). The majority of respondents who do not own dog (91.7%) said it was to avoid dog bites. A significant proportion of respondents (48.0%) who kept dog could not mention any dog disease or disease transmitted by dogs. The implications of these findings are very critical in the control of rabies and other dog-borne disease and mobilization of residents for more responsible dog ownership in Nigeria.


Omudu, E. A., Okpe, G., & Adelusi, S. M. (2010). Studies on Dog Population in Makurdi, Nigeria (II): A Survey of Ectoparasite Infestation and its Public Health Implications. Journal of Research in Forestry, Wildlife and Environment, 2(1), 94-106.

This study investigated the current status of dog infestation by ectoparasites, compared infestation between stray and restricted dogs and investigated some beliefs and practices by dog owners in Makurdi. Ectoparasites were collected using the body brushing and hand-picking methods and identified by standard methods. Dog owners' attitude and perceptions were investigated using structured questionnaires. The prevalence of infestation with ectoparasites among male dogs was 31.5%, though this rate was higher when compared with female dogs that had infestation rate of 23.5%. The difference was not statistically significant (X²= 11.4, df = 1, P > 0.05). Male dogs accounted for 57.8% of the total ectoparasites collected during this study. Stray dogs accounted for 56% of total dogs examined during this study and 58.3% of the ectoparasites were recovered from them. The infestation rates between stray and restricted dogs was statistically significant (X²= 14, df =1, P<0.05). The relative abundance of Rhipicephalus species (53.5%) was statistically highest. Other species of ticks encountered were Boophilus (31.4%) and Amblyomma (8.4%). Lice and fleas recovered from the dogs during this study belong to Linognathus and Ctenocephalis species respectively. Of the dog-borne disease listed, rabies was the most frequently mentioned by 56% of respondents while only 5.2% mentioned tick infestation as potential health risk to dogs and humans. Bathing dogs with brush, soap and detergents (59.6%) was the most popular method of cleaning dogs in Makurdi. This study demonstrated that several dog owners in Makurdi do not have the adequate dog-care information that will protect the health of their pets and safe-guard human health. 

Planning cat eradication on Guadalupe Island

Luna-Mendoza,L., J. M. Barredo-Barberena, J. C. Hernández-Montoya, A. Aguirre-Muñoz, F. A. Méndez-Sánchez, A. Ortiz-Alcaraz, & M. Félix-Lizárraga. 2011. Planning for the eradication of feral cats on Guadalupe Island, México: home range, diet, and bait acceptance. Pages 192-197 In: Veitch, C. R.; Clout, M. N. and Towns, D. R. (eds.). 2011. Island invasives: eradication and management. IUCN, Gland, Switzerland.

Feral cats (Felis catus) introduced to new environments have caused the extinction of many vertebrate species, including six species of birds on Guadalupe Island, México. To save species from extinction and restore natural processes, cats have been eradicated from islands using a variety of techniques. Eradication campaigns have to be planned carefully; ideally supported by information about the population to be eradicated. Our study focuses on home range estimation (fixed kernel); bait consumption by feral cats and non-target species; and diet of feral cats on Guadalupe Island. Home range was 76 to 1098 ha (KE 95) and core areas 21 to 196 ha (KE 50). Feral cats and non-target species including Guadalupe junco (Junco hyemalis insularis), Guadalupe rock wren (Salpinctes obsoletus guadalupensis), western gull (Larus occidentalis), and house mouse (Mus musculus) consumed baits. Items most commonly found in diet samples were mice (66.5%) and birds (16.8%). Male cats were 2.9 ± 0.6 kg, and females 2.4 ± 0.9 kg. The results of this study will inform eradication decisions for Guadalupe Island, especially regarding the use of poison baits.

Cats milking seals!!!

Juan-Pablo Gallo-Reynoso, J.P. & C. L. Ortiz. 2010. Feral cats steal milk from northern Elephant Seals. THERYA, 1(3): 207-212

Feral cats abound at Isla de Guadalupe; they forage on birds, mice, and placental tissue as well as carcasses of northern elephant seals (Mirounga angustirostris), Guadalupe fur seal (Arctocephalus townsendi), California sea lions (Zalophus californianus) and stranded cetaceans such as Cuvier’s beaked whale (Ziphius cavirostris). We have found that feral cats are also drinking elephant seal’s milk, stealing it directly from the teats of nursing females. The amount of energy obtained this way might be significant for feral cats in the northern elephant seal rookeries on the island.

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.

Read a short review about belling effectiveness

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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Read a short review about belling effectiveness