Predation by domestic cat in a British village

Churcher , P.B. & J.H. Lawton. 1987. Predation by domestic cats in an English (UK) village. Journal of Zoology. (London.) 212: 439-455

We studied predation by approximately 70 domestic cats (Felis catus L.) in the Bedfordshire village of Felmersham over a one-year period. All the prey items brought home by virtually all the cats in the village were recorded and, where possible, identified. A total of 1090 prey items (53i5 mammals, 297 birds and 258 unidentified animals) were taken, an average of about 14 per cat per year. Twenty two species of birds and 15 species of mammals were identified. The most important items were woodmice (17%), house sparrows (16%) and bank voles (14%).

Old cats of both sexes caught fewer prey over the year than young cats. Female cats on the edge of the village also caught more prey than female cats in intermediate or central areas of the village; male cats showed no such effect. The type of prey caught also varied with position in the village; ‘core’ cats caught proportionately more birds than ‘edge’ cats. There was some indication in the data that cats caught fewer prey in areas where cat density was highest, but this effect was impossible to disentangle from position in the village. Weather apparently influenced hunting success. Temperature had no direct influence, but fewer prey were caught in winter; cats also caught less on wet days and windy days.

Estimates of the number of house sparrows in the village at the start of the breeding season, and the number of sparrows known to have been caught by the cats, suggest that at least 30% of the sparrow deaths in the village were due to cats. Domestic cats would appear to be major predators in this typical English village.

Impact of domestic cats in an urban area

Baker, P. J., A. J. Bentley, R. J. Ansell, & S. Harris. 2005. Impact of predation by domestic cats Felis catus in an urban area. Mammal Review 35:302–312.

As companion animals, domestic cats Felis catus can attain very high densities, and have the potential to exert detrimental effects on prey species. Yet, there is a paucity of information on the impact of cat predation in urban areas, where most cats are likely to be present.

We quantified the minimum number of animals killed annually by cats in a 4.2-km2 area of Bristol, UK, by asking owners to record prey animals returned home by their pets. The potential impact of cat predation on prey species was estimated by comparing the number of animals killed with published estimates of prey density and annual productivity.

Predator density was 229 cats/km2.

Five mammal, 10 bird and one amphibian prey species were recorded. Mean predation rate was 21 prey/cat/annum. The most commonly recorded prey species was the wood mouse Apodemus sylvaticus.

Predation on birds was greatest in spring and summer, and probably reflected the killing of juvenile individuals. For three prey species (house sparrow Passer domesticus, dunnock Prunella modularis, robin Erithacus rubecula), estimated predation rates were high relative to annual productivity, such that predation by cats may have created a dispersal sink for juveniles from more productive neighbouring areas. The impact of cats on these species therefore warrants further investigation.

Do domestic cats impose an unsustainable harvest on urban bird populations?

van Heezik Y., A. Smyth, A. Adams & J. Gordon. 2010. Do domestic cats impose an unsustainable harvest on urban bird populations? Biological Conservation. 143(1): 121-130

We assessed the impact of domestic cats on population persistence of native and exotic urban bird populations using a model adjusted for habitat-specific catch rates, cat ownership and hunting activity data. GPS-derived home ranges of 32 cats and resource selection indices demonstrated the degree of penetration and preference for native vegetation fragments. Owners reported on prey brought back by 144 domestic cats in Dunedin, New Zealand, during 12 months. One third of cats never brought back prey, and 21% returned more than one item/month. Cats brought back a mean of 13.4 prey items/year (median = 4), with cats aged <1 year returning more prey than older cats. Birds were the most common prey, followed by rodents. Although cats penetrated adjacent vegetation fragments they did not catch more birds and preferred garden habitat, suggesting that predation pressure may be reduced in fragments. Cat home range size appears to be constrained by cat density while the number of birds caught depends on the density of available prey. Estimates of city-wide catch for six bird species were either more than total urban population size estimates or close to lower confidence intervals. Modelling of three species indicated low likelihood of population persistence with cat predation. The observed persistence of these prey species suggests a meta-population structure with urban populations acting as sinks with source populations located on the city fringe.

Demography of a common urban bird

Balogh, A.L., T.B. Ryder & P. P. Marra. 2011. Population demography of Gray Catbirds in the suburban matrix: sources, sinks and domestic cats. Journal of Ornithology, DOI 10.1007/s10336-011-0648-7

Understanding factors that limit the productivity and survival of birds in rapidly changing human-dominated landscapes are key to managing future population persistence. To date, few studies have quantified both nest
success and post-fledging survival for birds breeding within the suburban matrix. Here, we estimated nest success and juvenile post-fledging survival for Gray Catbirds (Dumetella carolinensis) and used those site-specific parameters to model source–sink dynamics at three sites in suburban Washington DC (USA). Cumulative nest success probability varied substantially among suburban sites and indicated that in some cases suburban habitats may provide suitable breeding sites for passerine birds. In addition, we documented the effects of sex and brood size on post-fledging survival rates and determined the role of predation on dispersing fledglings. Like nest success, estimates of post-fledging juvenile survival also varied among sites and highlight the importance of site-specific demographic estimates in urban habitats. Predation accounted for 79% of all mortalities, with 47% of known predation events attributable to domestic cats (Felis catus). Our models of source–sink dynamics underscore the importance of seasonal recruitment parameters for calculating population growth rate and subsequent persistence. This study provides parameter estimates for two critical life history stages in the avian annual cycle in the suburban matrix and posits that predation drives differential nest and post-fledging survival within human-dominated environments.