Food selection by the domestic cat

Bradshaw, J. W., Goodwin, D., Legrand-Defretin, V., & Nott, H. M. (1996). Food selection by the domestic cat, an obligate carnivore. Comparative Biochemistry and Physiology Part A: Physiology, 114(3), 205-209.


The domestic cat Felis silvestris catus is the most accessible member of the family Felidae for the study of the relationship between food selection and nutrition. In contrast to pack-living animals such as the dog, and opportunistic omnivores such as the rat, the cat is generally able to maintain its normal body weight even when allowed ad libitum access to palatable food by taking small meals and adjusting intake according to the energy density of the food(s) available. The most extreme adaptations to carnivory discovered to data lie in the taste buds of the facial nerve, which are highly responsive to amino acids and unresponsive to many mono- and disaccharides. Preferences for particular foods can be modified by their relative abundance, their novelty, and by aversive consequences such as emesis: the mechanisms whereby these are brought about appear to be similar to those used by omnivorous mammals.

Do scavenging dogs still prefer meat?

Bhadra, A., Bhattacharjee, D., Paul, M., Singh, A., Gade, P. R., Shrestha, P., & Bhadra, A. (2015). The meat of the matter: a rule of thumb for scavenging dogs?. Ethology Ecology & Evolution, 1-14.

Animals that scavenge in and around human settlements need to utilise a broad range of resources, and thus generalist scavengers are likely to be better adapted to human-dominated habitats. In India, free-ranging dogs (Canis lupus familiaris) live in close proximity with humans in diverse habitats, from forest fringes to metropolises, and are heavily dependent on humans for their food. It has been argued that the ability to digest carbohydrates was one of the driving forces for dog domestication. Though dogs are better adapted to digest carbohydrates than other canids, pet dogs show a clear preference for animal proteins. Our observations on streets of urban and semi-urban localities show that the free-ranging dogs are scavengers which primarily receive carbohydrate-rich food from humans. Their source for animal protein is typically garbage bins and leftovers, and such resources are rare. Using a series of field-based experiments, we test if the free-ranging dogs have adapted to a generalist scavenging lifestyle by losing preference for animal protein. Our experiments show that the free-ranging dogs, which are descendants of the decidedly carnivorous gray wolf (Canis lupus lupus), have retained a clear preference for meat, which is manifested by their choice of anything that smells of meat, irrespective of the actual nutrient content. The plasticity in their diet probably fosters efficient scavenging in a competitive environment, while a rule of thumb for preferentially acquiring specific nutrients enables them to sequester proteins from the carbohydrate-dominated environment.

Feeding habits of house and feral cats on small Adriatic islands

Lanszki J., Kletečki E., Trócsányi B., Mužinić J., Széles G.L. & Purger J.J. 2015  (in press) Feeding habits of house and feral cats (Felis catus) on small Adriatic islands (Croatia). North-Western Journal of Zoology (online first): art.151708

The domestic cat (Felis catus), a globally recognised invasive predator, was introduced to the Adriatic islands (Croatia), but its feeding ecology and impacts on biodiversity in this region is unknown. We studied the feeding habits of house cats living in villages and feral cats on the outskirts of villages on two small islands (Olib and Silba) by analysing faecal samples collected in the spring and autumn periods. Our hypothesis was that the feeding strategies of cats as top mammalian predators vary in different environments, due to significant dissimilarities in their food resources. We surveyed the abundance of cats and their primary food types, e.g. small mammals, birds, rabbits Oryctolagus cuniculus, and lizards. Our results suggest that house cats fed most often on birds and household food, while feral cats ate mostly small mammals and lizards. Feral cats preferred the invasive mesopredator black rat (Rattus rattus) (Ivlev’s index of preference, feral cats Ei = 0.72, house cats Ei = 0.14), suggesting that cats might have an effect on rat populations. Common rabbits had a low density and were preyed on only occasionally. In both cat groups, predation on birds was more frequent during autumn migration when bird abundance was higher, than in the spring breeding period. Both groups were food generalists but in different ways, which is a fact that should be considered in planning predator pest control on the islands.

Different cat diet between islands

Bonnaud, E., Palmas, P., Bourgeois, K., Ollier, S., Zarzoso-Lacoste, D., & Vidal, E. (2015). Island specificities matter: cat diet differs significantly between islands of a major breeding archipelago for a vulnerable endemic seabird. Biological Invasions, 1-15.

Domestic cats are one of the most widespread predators on islands worldwide and are responsible for numerous reductions and extinctions of species on islands. The three main islands of the Hyères Archipelago house one of the largest colonies of the Mediterranean endemic Yelkouan shearwater Puffinus yelkouan that has recently been up-listed by the IUCN to ‘vulnerable’. The main objectives of this study were to assess the diet of cats and to study the effect of cat predation on Yelkouan shearwater populations at the archipelago scale. The diet of cats was studied using scat analyses according to years and seasons for each island. Simultaneously, Yelkouan shearwater breeding success was monitored during a period of 8 years on Port-Cros and Porquerolles, and 3 years on Le Levant. Descriptive analyses and GLM were used to compare data gathered on each island. At the archipelago scale, cats preyed strongly upon introduced mammals and shearwaters. Surprisingly, large differences appeared in cats’ diet according to the island considered. The Yelkouan shearwater was the primary prey of cats on Le Levant, but secondary on Port-Cros and Porquerolles. Cat predation was mainly concentrated during the shearwater prospecting period, when birds arrive at the colonies and look for a mate (if they are not already paired) and a burrow before breeding. Consequently cat impact was low on shearwater breeding success. However, this study demonstrates that the cat management conducted on Port-Cros was positive for fledging success. The successful cat eradication on Port-Cros supports the need to continue working for Yelkouan shearwater conservation with Le Levant as a priority, because this is where the colonies are largest and predation on Yelkouan shearwaters is very high.

Feral cat diet in Australia

Doherty, T.S., R. A. Davis, E. J. B. van Etten, D. Algar, N. Collier, C.R. Dickman, G. Edwards, P. Masters, Russell Palmer & S. Robinson. 2015. A continental-scale analysis of feral cat diet in Australia. Journal of Biogeography.

Aim
Reducing the impacts of feral cats (Felis catus) is a priority for conservation managers across the globe, and success in achieving this aim requires a detailed understanding of the species’ ecology across a broad spectrum of climatic and environmental conditions. We reviewed the diet of the feral cat across Australia and on Australian territorial islands, seeking to identify biogeographical patterns in dietary composition and diversity, and use the results to consider how feral cats may best be managed.

Location
Australia and its territorial islands.

Methods
Using 49 published and unpublished data sets, we modelled trophic diversity and the consumption of eight food groups against latitude, longitude, mean temperature, precipitation, environmental productivity and climate-habitat regions.

Results
We recorded 400 vertebrate species that feral cats feed on or kill in Australia, including 28 IUCN Red List species. We found evidence of continental-scale prey-switching from rabbits to small mammals, previously recorded only at the local scale. The consumption of arthropods, reptiles, rabbits, rodents and medium-sized native mammals varied with different combinations of latitude, longitude, mean annual precipitation, temperature and environmental productivity. The frequency of rodents and dasyurids in cats’ diets increased as rabbit consumption decreased.

Main conclusions
The feral cat is an opportunistic, generalist carnivore that consumes a diverse suite of vertebrate prey across Australia. It uses a facultative feeding strategy, feeding mainly on rabbits when they are available, but switching to other food groups when they are not. Control programmes aimed at culling rabbits could potentially decrease the availability of a preferred food source for cats and then lead to greater predation pressure on native mammals. The interplay between cat diet and prey species diversity at a continental scale is complex, and thus cat management is likely to be necessary and most effective at the local landscape level.

Indirect dispersal of seeds by lizard-preying cats

Nogales, M., Medina, F. M., & Valido, A. (1996). Indirect seed dispersal by the feral cats Felis catus in island ecosystems (Canary Islands). Ecography, 19(1), 3-6.

In this paper we present an unusual incidence of an introduced Camivora Felis catus as indirect seed disperser of plants that produce fleshy fruits in different ecosystems in the Canary Islands. Four hundred and twenty six seeds from at least 8 fleshy fruit plant species have been identified in the analysis of 1047 scat groups, the majority of them being found in the lower habitats (<600 m a.s.l.) of the Canary archipelago. Seeds from two plant species were significantly matched with the presence of lizard prey, and fruits of Juniperus phoenicea, Neochamaelea pulverulenta and Withania aristata were directly consumed by the cats. Passing through the gut of the Gallotia galloti(Lacertidae) and Felis catus apparently does not damage the seeds. At the moment, the phenomenon studied in this paper does not seem to have a great quantitative importance in the natural regeneration of the plants if we compare the direct vs indirect seed dispersal.

Diet of the feral ca in central Australian grasslands during population cycles of its principal prey

Yip, S. J., Rich, M. A., & Dickman, C. R. (2014). Diet of the feral cat, Felis catus, in central Australian grassland habitats during population cycles of its principal prey. Mammal Research, 1-12.

Foraging theory predicts that animals should forage so as to maximize their net rate of energy gain or to minimize their risk of starvation. In situations where prey numbers fluctuate dramatically, theory predicts further that foragers will eat ‘optimal’ prey when it is abundant but expand their diet to include other prey types when the optimal prey is scarce; this is the alternative prey hypothesis. Here, we test this prediction by analyzing the diet of a mammalian predator, the feral house catFelis catus, during periods of scarcity and abundance of the long-haired rat Rattus villosissimus. We also investigate whether the body condition of feral cats differs during different stages of the prey population cycle. Feral cats were shot during culling operations in semi-arid grassland habitats in central Queensland, Australia, and the stomach contents later identified. We found that the body condition of feral cats did not differ between phases of the prey population cycle, but the diets of cats culled when long-haired rats were scarce were significantly more diverse than when this rodent was abundant. Rats comprised about 80 % of cats’ diet by volume and frequency of occurrence when they were present, whereas birds, reptiles and invertebrates comprised the bulk of the diet when rats were not available. We conclude that, whilst feral cats are often thought to be specialist predators, they may be better considered as facultative specialists that will shift their diet in predictable ways in response to changes in the abundance of primary prey.

Ecology of the feral cat on Macquarie Island

Jones, E. (1977). Ecology of the feral cat, Felis catus (L.),(Carnivora: Felidae) on Macquarie Island. Wildlife Research, 4(3), 249-262.

On Macquarie Island from December 1973 to March 1975 the diet of feral domestic cats (Felis catus) was estimated. There was rabbit (Oryctolagus cuniculus) in 82% of faeces and 71% of guts, rabbits under 600 g bodyweight, about 10 weeks old, were 81% of all rabbits eaten. There were Antarctic prion (Pachyptila desolata) and white-headed petrel (Pterodroma lessonii). Cats ate small numbers of rats, mice and wekas and scavenged on dead elephant seals and penguins, especially in winter. Availability of food in winter seemed to be an important factor limiting the population; adult population was estimated to be 250 to 500 and the area of the island is 120 km². Prion and white-headed petrel nest in burrows; there was little or no predation by cats on surface nesters such as albatross, giant petrel, southern skua or southern black-backed gull, or on live penguin.

Diet of feral cats in NZ forest

Fitzgerald, A. M., & Karl, B. J. (1979). Foods of feral house cats (Felis catus L.) in forest of the Orongorongo Valley, Wellington. New Zealand journal of zoology,6(1), 107-126.

The foods of feral house cats in forest in the Orongorongo Valley, Wellington, were studied over 3 years and related to the availability of prey. Some cats were trapped, tagged, and released, and could be identified individually by coat colour and pattern. The number of cats, estimated from live-trapping and sightings, was stable during the study. Examination of 677 scats revealed that mammals (rat, rabbit, opossum, mouse, and stoat, in descending order of importance) formed the bulk of the diet by weight. Remains of birds occurred in 12% of scats, but birds were estimated to form only 4.5% by weight of the diet. Insect fragments were present in many scats; wetas (Orthoptera), cicadas (Hemiptera), and beetles (Colcoptera) were important seasonally. Although eaten in large numbers, they contributed very little by weight to the diet. Populations of rats, rabbits, and opossums were fairly stable during the study; mice were abundant for most of the first 18 months, but were scarce in the last year. The literature on the food habits of feral house cats is reviewed; it emphasises that cats are primarily predators of small mammals (rodents and lagomorphs). Predation by feral cats can be important in holding rat and rabbit populations at low densities and in reducing seasonal fluctuations in their numbers. Cats can also exert heavy predation pressure on low-density mouse populations. Although the cats now eat few birds, they may have been responsible for reducing the numbers of some forest birds in the past.

Feral house diet in Victoria

Coman, B. J., & Brunner, H. (1972). Food habits of the feral house cat in Victoria. The Journal of Wildlife Management, 36 (3): 848-853.

A total of 128 feral domestic cats (Felis catus) were collected from two different habitat types in Victoria. The stomachs of 80 of these cats contained food. Mammals, chiefly rabbits (Oryctolagus cuniculus), small murids, and phalangers, comprised some 88 percent, by volume, of the total dietary intake. Birds, cold-blooded vertebrates, and invertebrates were of secondary importance in the diet, accounting for only 5.2 percent, by volume, of the total intake. Grass and small twigs occurred frequently in the stomachs, but the volume represented was small (1.4 percent). Other items, mainly carrion and cat fur, accounted for 5.4 percent of the intake on a volume basis. Feral cats from undeveloped bush areas relied heavily on small indigenous mammals, whereas rabbits and house mice (Mus musculus) were the main mammalian prey species eaten in improved and semi-improved agricultural areas. Remains of indigenous mammals were not found in the stomachs of cats from the latter areas. It appears that feral cats are opportunist predators and scavengers and that the level of predation on any one prey type will depend largely on its relative availability. As a consequence, predation on native mammals is probably limited to those undeveloped areas of bush and scrub where such species are more plentiful.

Feeding ecology and population dynamics of the feral cat in Australia

Molsher, R., Newsome, A., & Dickman, C. (1999). Feeding ecology and population dynamics of the feral cat (Felis catus) in relation to the availability of prey in central-eastern New South Wales. Wildlife Research, 26(5), 593-607.

The diet of feral cats (Felis catus) was studied at Lake Burrendong, central-eastern New South Wales, from July 1994 to June 1997. Mammals were the major prey in 499 scats that were analysed. Rabbits (Oryctolagus cuniculus) were the staple prey, while carrion was an important secondary food. Invertebrates, other mammalian prey, vegetation, birds and reptiles were generally minor components of the diet. Few significant seasonal differences in diet were found; however, invertebrates contributed less and possums more to the diet in winter and summer respectively. A significant dietary response was found to changes in rabbit abundance, but not for the other prey types. Cats continued to prey heavily on rabbits even after a 90% decline in rabbit abundance occurred, which coincided with the advent of Rabbit Calicivirus Disease (RCD). House mice (Mus domesticus) increased in importance in the diet ten months post-RCD. Although the abundance of cats was correlated with the abundance of some prey species, other factors may have influenced the observed patterns; these are discussed.

Diet of fox, dog and cat in south-eastern Victoria

Triggs, B., Brunner, H., & Cullen, J. M. (1984). The food of fox, dog and cat in Croajingalong National Park, south-eastern Victoria. Wildlife Research, 11(3), 491-499.

The diet of foxes, dogs and cats living in Croajingalong National Park in extreme south-easten Victoria was studied during 1979 and 1980. From 1397 scats collected over 20 months, remains of 22 indigenous and 7 introduced mammal species were identified. Remains of ringtail possums Pseudocheirus peregrinus predominated in the scats from all three predators (fox 58%, cat 56% and dog 38%). Other main prey species for the fox and cat were Antechinus spp.(24% and 15% respectively) and Rattus spp. (15% and 19%) and for the dog two species of wallabies, Macropus rufogriseus and Wallabia bicolor (34%), wombat Vombatus ursinus (11%), Antechinus spp.(l5%) and Rattus spp.(10%). Nonmammalian items for the three predators were birds, reptiles, fish, insects, crustaceans, molluscs and plant material.

Comparison between feral cat and fox diets in Australia

Catling, P. C. (1988). Similarities and contrasts in the diets of foxes, Vulpes vulpes, and cats, Felis catus, relative to fluctuating prey populations and drought. Wildlife Research, 15(3), 307-317.

The diets of the fox, Vulpes vulpes, and feral cat, Felis catus, were studied at Yathong Nature Reserve in semi-arid western New South Wales. The overall occurrence of rabbit was 45.1% in stomachs of foxes and 54.0% in cats, representing 51.3 and 82.6% respectively of the weight of stomach contents. Both predators exhibited a functional response to rabbits, Oryctolagus cuniculus, (their staple prey) during the rabbit breeding season. Predation on rabbits was greatest on an increasing prey population during good pasture conditions and a decreasing population during drought. After the rabbit breeding season, diet changed to other prey and resulted in an annual prey cycle which was similar for foxes and cats. Both predators successfully co-exist in the semi-arid environment by primarily utilising different age groups of the same staple prey and to some extent different supplementary prey. Foxes mainly ate adult rabbits and cats young rabbits. During the drought foxes preyed heavily on adult rabbits; cats ate some rabbits but relied heavily on other food sources. The supplementary prey of foxes were invertebrates, birds, reptiles and carrion; small mammals and fruits opportunely eaten. Invertebrates, birds, reptiles and small mammals were supplementary prey for cats with carrion opportunely eaten.

Pet cats' impact on prey populations

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

This paper attempts to apply theory from more than 100 years of scientific experience and experimentation in predator-prey ecology and introduced species ecology to predict the likely effects of predation by domestic cats (Felis catus) on prey populations and community structure. Those aspects of the predatory behaviour of domestic cats which are of most importance in predicting their impact on prey populations: I) the degree of prey selectivity or 'dietary preference'; 2) the exhibition of switching behaviour; 3) changes in predatory activity in response to changes in prey density; and 4) the extent to which high and constant densities of the predator are ameliorated by reduced prey consumption rates as a result of dietary supplement.

In suburban environments, the influence of predation by domestic cats on prey abundance and community structure probably increases, relative to the influence of habitat change, with increasing suburb age, particularly in the absence of physical disturbances such as fire. However, it may never be as important as habitat availability and indeed may never be significant at all. Removal of the predator may allow some animal species to increase in abundance but others may decline. The details of these changes are very difficult to predict. Similarly, following predator removal, total species diversity is as likely to decline due to increased inter-specific competition, as it is to increase due to the invasion of species previously excluded by predation.
In remnant habitat, the impact of predation by domestic cats is probably less likely to be important in determining the relative abundance of the more common species than in suburban environments, but more likely to contribute to local extinctions of rare species. As in suburban environments, predation on introduced species in remnant habitat may reduce predation on native species. However, the ability of domestic cats to control introduced species which prey on, or compete with, native species will be difficult to demonstrate. In light of this uncertainty, any attempt to prevent domestic cats hunting in remnant habitat patches should be integrated with a program to eliminate or control populations of other introduced species, such as black rats and rabbits, which are preyed upon by domestic cats and are known to prey on or compete with native species.

Cats on Dassen Island

Apps, P. 1984. Cats on Dassen Island. Acta Zool. Fennica, 172: 115-116.

Dassen Island, a small island off the west coast of South Africa, is an important nesting site for sea birds. Introduced mammals include Felis catus and Oryctolagus cuniculus. Studies on the ecological impact of the feral cat population showed that birds and rabbits contributed almost equally to the diet of the cats, but that most of the birds were scavenged, so that the impact of cat predation on their populations was insignificant, while rabbits were hunted and the effect may have been ecologically important. The cats' ecological role was influenced strongly by their behaviour, which must be considered in the planning of conservation or control measures.

Spatial organization and habitat use of feral cats in California

Hall, L. S., Kasparian, M. A., Van Vuren, D., & Kelt, D. A. (2000). Spatial organization and habitat use of feral cats (Felis catus L.) in Mediterranean California. Mammalia, 64(1), 19-28.

We report on a preliminary study of the spatial organization, habitat use, and diet of feral cants (Felis catus) in a riparian reserve in Central California, to assess potential impacts of this exotic predator on native species. Home ranges of adult cats averaged 31,7 ha and did not differ significantly by sex and season. Home ranges also showed little overlap, suggesting a territorial social system. Cats strongly preferred riparian habitats and foraged primarily on native species of small mammals, especially California voles (Microtus californicus) and Botta's pocket gophers (Thomomys bottae), although birds, insects, and exotic rodents were also eaten. The preference for riparian habitats and native preys suggests that impacts on biodiversity by feral cats may be great, especially in Mediterranean climates where riparian communities already are heavily impacted by urbanisation and agriculture.

Cats domesticated themselves

Hu, Y., Hu, S., Wang, W., Wu, X., Marshall, F. B., Chen, X., Hou, L. & Wang, C. (2013). Earliest evidence for commensal processes of cat domestication. Proceedings of the National Academy of Sciences, 201311439.

Domestic cats are one of the most popular pets globally, but the process of their domestication is not well understood. Near Eastern wildcats are thought to have been attracted to food sources in early agricultural settlements, following a commensal pathway to domestication. Early evidence for close human–cat relationships comes from a wildcat interred near a human on Cyprus ca. 9,500 y ago, but the earliest domestic cats are known only from Egyptian art dating to 4,000 y ago. Evidence is lacking from the key period of cat domestication 9,500–4,000 y ago. We report on the presence of cats directly dated between 5560–5280 cal B.P. in the early agricultural village of Quanhucun in Shaanxi, China. These cats were outside the wild range of Near Eastern wildcats and biometrically smaller, but within the size-range of domestic cats. The δ13C and δ15N values of human and animal bone collagen revealed substantial consumption of millet-based foods by humans, rodents, and cats. Ceramic storage containers designed to exclude rodents indicated a threat to stored grain in Yangshao villages. Taken together, isotopic and archaeological data demonstrate that cats were advantageous for ancient farmers. Isotopic data also show that one cat ate less meat and consumed more millet-based foods than expected, indicating that it scavenged among or was fed by people. This study offers fresh perspectives on cat domestication, providing the earliest known evidence for commensal relationships between people and cats.

Population dynamics and diet of feral cats and foxes in South Australia

Read, J., & Bowen, Z. (2001). Population dynamics, diet and aspects of the biology of feral cats and foxes in arid South Australia. Wildlife Research, 28(2), 195-203.

Average cat and fox densities at Roxby Downs, in northern South Australia, of 0.8 and 0.6 km^-2  respectively, determined through spotlight counts over a 10-year period, probably considerably underestimate true densities. Peak rabbit populations coincided with high fox numbers, which probably suppressed cat densities. Cat abundance peaked when fox numbers were low but rabbit numbers were relatively high.

When abundant, rabbits were the principal prey of both cats and foxes. Declines in rabbits numbers coincided with dramatic declines in fox numbers. By contrast, declines in cat populations were less marked, presumably because they could more effectively switch to hunting a wide range of native vertebrates. Sand-dwelling lizards, house mice and common small passerines were the most abundant non-rabbit, vertebrate prey taken by cats. We estimate that annual cat predation accounted for approximately 700 reptiles, 150 birds and 50 native mammals per square kilometre, whereas foxes consumed on average 290 reptiles per square kilometre and few native mammals and birds in the Roxby Downs region each year.

Male cats and foxes were heavier than females. Feral cats typically weighed less than 4.0 kg, and cats weighing less than 2.5 kg typically preyed on more native vertebrates than did larger cats. Male and female cats were both typically tabby coloured, but a higher proportion of males were ginger in colour. Peak cat breeding coincided with rabbit and bird breeding and increased reptile activity during spring.

Cats prefer killing than eating

Adamec, R. E. (1976). The interaction of hunger and preying in the domestic cat (Felis catus): An adaptive hierarchy?. Behavioral Biology, 18(2), 263-272.

After being deprived of food for 48 hr six cats' food preferences for six types of food were determined. The food types were commercial beef, fish, and chicken cat foods, salmon, and freshly killed hooded rats, either warm or cooled. Food types were presented in pairs and preference was determined as the food types eaten most in a 1-hr period. After being deprived, the cats were then presented a choice between these foods in ascending order of preferences and a live hooded rat, on separate days. Cats were allowed to eat their preferred food for 45 sec prior to introducing the rat. In all cases cats stopped eating, traveled 4 ft, and leaped off a shelf to attack and kill the rat. They then brought the rat back to the food dish and resumed eating. In most cases the cats preferred the food they were eating to the rat prey. In only one case, when the most preferred food was being eaten, did the cat not attack. Quantitative measures of attack latency, biting, and latency to kill revealed a uniform attack pattern in all food-choice situations which did not differ from attacks seen when the cats were presented with a rat only. These data suggest that eating is not a terminal “consummatory” component of preying as a food-getting response. Hunger may be seen as a potentiator of a predatory tendency which takes precedence over food consumption. In view of the relative difficulty of feline prey capture in the wild for maintaining adequate food supply, the precedence of preying over eating may have the functional value of increasing food input by multiple kills if the opportunity arises.

Feral cats threaten endemic Barau's Petrel

Faulquier, L., Fontaine, R., Vidal, E., Salamolard, M., & Le Corre, M. (2009). Feral Cats Felis catus Threaten the Endangered Endemic Barau's Petrel Pterodroma baraui at Reunion Island (Western Indian Ocean). Waterbirds,32(2), 330-336.

Cats (Felis catus) were probably introduced to Reunion Island (Western Indian Ocean) in the seventeenth century and feral populations are now spread over all anthropogenic and native habitats. The diet of feral cats living in the breeding habitat of Barau's Petrel (Pterodroma baraui), an endemic and threatened seabird of Reunion Island, were studied. Results from the analysis of 217 scat (333 prey items) showed that Barau's Petrel were the most common prey of feral cats, followed by introduced rodents. Numerous dead birds at breeding colonies that had been killed by cats were found, 58% of the birds were adults. Given the high sensitivity of the population growth rate of a long-lived seabird to any additive mortality of adults, these results are particularly worrying. As this species is also threatened by massive light-induced mortality of fledglings, it is highly likely that this population is declining. A control of cats at breeding colonies is urgently needed to save this species from extinction.

Pinet, P., Salamolard, M., Probst, J.M., Russell, J.C., Jaquemet, S. & Le Corre, M. 2009. Barau’s Petrel Pterodroma baraui: history, biology and conservation of an endangered petrel. Marine Ornithology 37: 107–113.

The Barau’s petrel Pterodroma baraui is an endangered gadfly petrel endemic to Reunion Island. It nests in pristine cloud forests between 2200 m and 2800 m above sea level. Although locally abundant, this species is one of the least-studied seabirds in the world. The lack of basic biological information constrains effective conservation action. In this paper, we compile information on past and present status and distribution, ecology, threats and conservation actions. The objectives were to: (i) summarize current knowledge and identify major gaps, (ii) outline major threats to Barau’s Petrel and (iii) propose management actions to mitigate those threats. Critical gaps in our knowledge include (i) a lack of precise demographic parameters, (ii) the exact distribution of this species at sea and the factors that influence it, and (iii) habitat requirements associated with nesting. Barau’s Petrel is classified endangered (International Union for Conservation of Nature Red List 2008). The major threats include, in order of importance, predation by alien mammals, light-induced mortality and modification of nesting habitat. These threats affect the various age classes of the population (eggs, chicks, juveniles and adults) differently. A recent modelling exercise suggested the extinction of Barau’s Petrel in fewer than 100 years, attributable to feral cat predation at breeding colonies in the absence of cat control. The recent establishment of a National Park on Reunion Island should unify conservation and research actions, and prioritise controlling feral cats in breeding colonies. This control should commence as soon as possible in association with a dedicated education program on the effects of feral cats on the Barau’s Petrel population.