Exposure to predators reduce immune response in birds

Navarro, C., De Lope, F., Marzal, A., & Møller, A. P. (2004). Predation risk, host immune response, and parasitism. Behavioral Ecology, 15(4), 629-635.

Predation risk may affect the allocation priorities of limiting resources by potential prey. Investment in immune function should receive reduced priority, when hosts are exposed to predators because of the costs of immune function. We tested this hypothesis by randomly exposing adult house sparrows, Passer domesticus, to either a cat, Felis catus, or a rabbit, Oryctolagus cuniculus, for 6 h while assessing their ability to raise a T-cell–mediated immune response to a challenge with phytohemagglutinin. Sparrows exposed to a cat had a significant reduction of, on average, 18% and 36% in T-cell response in two different experiments compared with sparrows that were exposed to a rabbit. In a field experiment with a barn owl, Tyto alba, or a rock dove, Columba livia, placed next to a nest-box during laying, we found a mean reduction in T-cell–mediated immune response of 20%. In males, the reduction in cell-mediated immune response owing to cat exposure increased with increasing size of the badge, which is a secondary sexual character, but only during the breeding season. In a third experiment, house sparrows were either exposed to a barn own, T. alba, or a rock dove, C. livia, and development of malarial infections was recorded during the following 6 weeks. Individual sparrows exposed to a predator had a higher prevalence and intensity of Haemoproteus malarial infection than did control individuals. Therefore, exposure to predators reduced their ability of hosts to cope with parasitism mediated through effects on immune function.

Feral cat suppression by apex predator reduces the risk of predation perceived by small prey

Gordon, C. E., Feit, A., Grüber, J., & Letnic, M. (2015). Mesopredator suppression by an apex predator alleviates the risk of predation perceived by small prey. Proceedings of the Royal Society B: Biological Sciences, 282(1802), 20142870.

Predators can impact their prey via consumptive effects that occur through direct killing, and via non-consumptive effects that arise when the behaviour and phenotypes of prey shift in response to the risk of predation. Although predators' consumptive effects can have cascading population-level effects on species at lower trophic levels there is less evidence that predators' non-consumptive effects propagate through ecosystems. Here we provide evidence that suppression of abundance and activity of a mesopredator (the feral cat) by an apex predator (the dingo) has positive effects on both abundance and foraging efficiency of a desert rodent. Then by manipulating predators' access to food patches we further the idea that apex predators provide small prey with refuge from predation by showing that rodents increased their habitat breadth and use of ‘risky′ food patches where an apex predator was common but mesopredators rare. Our study suggests that apex predators' suppressive effects on mesopredators extend to alleviate both mesopredators' consumptive and non-consumptive effects on prey.

Cat predation risk contribute to senescence in swallows

BALBONTÍN, J., & MØLLER, A. 2015. Environmental conditions during early life accelerate the rate of senescence in a short-lived passerine bird. Ecology

Environmental conditions experienced in early life may shape subsequent phenotypic traits including life history. We investigated how predation risk caused by domestic cats (Felis silvestris catus) and local breeding density affected patterns of reproductive and survival senescence in Barn Swallows (Hirundo rustica) breeding semicolonially in Denmark. We recorded the abundance of cats and the number of breeding pairs at 39 breeding sites during 24 years and related these to age-specific survival rate and reproductive senescence to test predictions of the life history theory of senescence. We found evidence for actuarial senescence for the first time in this species. Survival rate increased until reaching a plateau in midlife and then decreased later. We also found that survival rate was higher for males than females. Local breeding density or predation risk did not affect survival as predicted by theory. Barn Swallows with short lives did not invest more in reproduction in early life, inconsistent with expectations for trade-offs between reproduction and survival as theory suggests. However, we found that the rate of reproductive decline during senescence was steeper for individuals exposed to intense competition, and predation pressure accelerated the rate of reproductive senescence, but only in sites with many breeding pairs. These latter results are in accordance with one of the predictions suggested by the life history theory of aging. These results emphasize the importance of considering intraspecific competition and interspecific interactions such as predation when analyzing reproductive and actuarial senescence.

Mobility of deers and their arassment by dogs

Progulske, D. R., & Baskett, T. S. (1958). Mobility of Missouri deer and their arassment by dogs. The Journal of Wildlife Management, 184-192.

There is little information on the mobility of the white-tailed deer (Odocoileus virginianus) in the middle United States; data are equally limited on the mobility of white-tails on land that is primarily agricultural or where ther's a yearlong harassment by dogs...

Evolution of antipredator behavior in an island lizard species: the sum of all fears?

Brock, K. M., Bednekoff, P. A., Pafilis, P., & Foufopoulos, J. (2014). Evolution of antipredator behavior in an island lizard species, Podarcis erhardii (Reptilia: Lacertidae): the sum of all fears?. Evolution.

Organisms generally have many defenses against predation yet may lack effective defenses if from populations without predators. Evolutionary theory predicts that ‘costly’ antipredator behaviors will be selected against when predation risk diminishes. We examined antipredator behaviors in Aegean wall lizards, Podarcis erhardii, across an archipelago of land-bridge islands that vary in predator diversity and period of isolation. We examined two defenses, flight initiation distance and tail autotomy. Flight initiation distance generally decreased with declining predator diversity. All predator types had distinctive effects on flight initiation distance with mammals and birds having the largest estimated effects. Rates of autotomy observed in the field were highest on predator-free islands yet laboratory-induced autotomy increased linearly with overall predator diversity. Against expectation from previous work, tail autotomy was not explained solely by the presence of vipers. Analyses of populations directly isolated from rich predator communities revealed that flight initiation distance decreased with increased duration of isolation in addition to the effects of current predator diversity, whereas tail autotomy could be explained simply by current predator diversity. Although selection against costly defenses should depend on time with reduced threats, different defenses may diminish along different trajectories even within the same predator-prey system.

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Domestic dogs in Wildlife habitats

Sime, C. A. 1999. Domestic Dogs in Wildlife Habitats. Pages 8.1-8.17 in G. Joslin and H. Youmans, coordinators. Effects of recreation on Rocky Mountain wildlife: A Review for Montana. Committee on Effects of Recreation on Wildlife, Montana Chapter of The Wildlife Society. 307pp.

It is difficult to segregate human demographic trends from trends in rural development and outdoor recreational participation in settings like the West where they appear to be interrelated. One extension of human recreation in wildlife habitats is the effect of disturbance, harassment, displacement, or direct mortality of wildlife attributable to domestic dogs that accompany recreationists. At some level, domestic dogs still maintain instincts to hunt and/or chase. Given the appropriate stimulus, those instincts can be triggered in many different settings. Even if the chase instinct is not triggered, dog presence in and of itself has been shown to disrupt many wildlife species. Authors of many wildlife disturbance studies concluded that dogs with people, dogs on-leash, or loose dogs provoked the most pronounced disturbance reactions from their study animals. During winter, concerns are primarily related to human activity on ungulate winter ranges. Dogs extend the zone of human influence when off-leash. Many ungulate species demonstrated more pronounced reactions to unanticipated disturbances, as a dog off-leash would be until within very close range. In addition, dogs can force movement by ungulates (avoidance or evasion during pursuit), which is in direct conflict with overwinter survival strategies which promote energy conservation. During summer, concerns are primarily related to the birth and rearing of young for all wildlife species. Dogs are noted predators for various wildlife species in all seasons. Domestic dogs can potentially introduce diseases (distemper, parvovirus, and rabies) and transport parasites into wildlife habitats. While dog impacts to wildlife likely occur at the individual scale, the results may still have important implications for wildlife populations. For most wildlife species, if a “red flag” is raised by pedestrian-based recreational disturbance, there could also be problems associated with the presence of domestic dogs. Managers may consider the following when evaluating recreational impacts of dogs in wildlife habitats: species biology, reproductive potential, abundance, density, distribution, degree of habitat specificity or reliance on certain habitat components, and predisposition and sensitivity to disturbance by other agents. This information is intended to increase awareness among natural resource professionals and the public about the potential implications of uncontrolled domestic dogs in wildlife habitats and to encourage responsible outdoor recreation ethics.

Birds' choice of song posts

Møller, A. P. (2011). Song post height in relation to predator diversity and urbanization. Ethology, 117(6), 529-538.

Birds may sing from positions in the vegetation (song posts) to allow efficient transmission of sexual and territorial vocal displays while simultaneously minimizing the risk of predation because of avian and mammalian predators. Because urban areas are deficient in specialized avian predators, but have many cats while the opposite is the case for nearby rural areas, urban birds should display higher in the vegetation. In a comparison of the abundance of predators in three cities (Oslo, Brønderslev, Orsay), I show that avian predators are more common in rural areas, while mammalian predators are more common in urban areas. Singing birds sang from higher positions in the vegetation of urban than nearby rural areas. Differences in song post heights between urban and rural areas were consistent among cities, suggesting inherent specific difference in microhabitat choice. Bird species that have become urbanized recently had similar song post heights in urban and rural habitats, while species that have been urbanized for a long time sang from relatively higher song posts in urban areas. These findings suggest that urban and rural birds differ in habitat use when singing. These differences in song post choice between urban and rural habitats may have a number of consequences for vocal displays in the two different habitats.

Escape behaviour related to different predators in urban or rural habitats

Møller, A. P., & Ibáñez-Álamo, J. D. (2012). Escape behaviour of birds provides evidence of predation being involved in urbanization. Animal Behaviour, 84 (2): 341–348

Altered predation risk in urban environments may contribute to animals becoming successfully urbanized by individuals from rural habitats. Escape behaviour has evolved to allow an individual to escape once captured by a predator. We tested whether altered predation risk in urban environments is associated with colonization of such habitats by comparing escape behaviour of 1132 individual birds belonging to 15 species from nearby rural and urban populations when captured by a human. Raptors (of which the Eurasian sparrowhawk, Accipiter nisus, was one of the most common species) were more common in rural than in urban habitats, whereas cats, Felis catus, showed the opposite pattern. There were consistent differences in escape behaviour between habitats, showing divergence in behaviour from the ancestral rural state. Urban birds wriggled less, showed higher tonic immobility, more often lost feathers, were less aggressive by biting less often, and emitted fear screams and alarm calls more often than rural birds. Furthermore, differences in escape behaviour between habitats were related to susceptibility to predation by sparrowhawks, as expected if differences in behaviour were due to differences in predation risk. Finally, an analysis of differences in escape behaviour between rural and urban birds revealed a significant relationship with time since urbanization, suggesting that escape behaviour has changed in urban environments over time. These findings suggest that release from predation and change in predator community associated with urbanization has altered the antipredator behaviour of birds colonizing towns and cities.

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Highlights

► We investigated escape behaviour of urban and rural birds. ► Urban birds tried to escape less actively and gave more alarm calls than rural birds. ► These differences were related to susceptibility to predation by sparrowhawks. ► The degree of divergence was related to time since urbanization. ► Predation is an important selection force driving adaptation to urban habitats.

Effect of guard dogs on gazelles

Gingold, G., Yom‐Tov, Y., Kronfeld‐Schor, N., & Geffen, E. (2009). Effect of guard dogs on the behavior and reproduction of gazelles in cattle enclosures on the Golan Heights. Animal Conservation, 12(2), 155-162.

Cattle on the Golan Heights are kept in enclosures and some of these enclosures have guard dogs. We studied the effect of such dogs on the behavior and breeding success of mountain gazelles Gazella gazella living within enclosures. We found that guard dogs have both direct and indirect effects on gazelles. Gazelles living in enclosures with dogs spent more time in vigilance behavior and running, and less time resting and walking, in comparison with gazelles in dog-free enclosures. In the absence of dogs, gazelle female herds in enclosures tended to stay closer to the cattle, but shunned away from them in the presence of the dogs, which, in turn, remained near the cattle. The percentage of fawns per female was higher in enclosures without dogs in comparison with those with dogs, but the difference was not significant. However, the largest of the enclosures with dogs, which had the largest number of gazelles, had only an average number of dogs in it. Hence, the gazelles in this enclosure were better able to avoid the dogs in comparison with those in smaller enclosures. Removing this enclosure from the overall calculation revealed that guard dogs have a significant negative effect on gazelle reproductive success. In two of the four enclosures with dogs no fawn still survived 6 months after birth, while in each of the four enclosures without dogs some fawns did survive to that age and beyond, suggesting that the dogs themselves may predate the fawns.

Domestic dogs and edge effect

Lacerda, A. C. R., Tomas, W. M., & Marinho‐Filho, J. (2009). Domestic dogs as an edge effect in the Brasília National Park, Brazil: interactions with native mammals. Animal Conservation, 12(5), 477-487.

Edge effects are a well-known result of habitat fragmentation. However, little has been published on fragmentation, isolation and the intrusive influence from the surrounding matrix at the landscape level. The objectives of the present study are to evaluate the presence of dogs in the Brasília National Park (BNP) in relation to habitat type and the influence from the surrounding matrix. In addition, this study examines the response of the native mammal fauna to the presence of dogs. Track stations were built along dirt roads in the BNP and subsequently examined for the presence or absence of tracks. We used a stepwise logistic regression to model the occurrence of five mammal species relative to habitat variables, with an α=0.05 to determine whether to enter and retain a variable in the model. A simulation of each species occurrence probability was conducted using a combination of selected habitat variables in a resource selection probability function. Results indicate a negative relationship between distance from the BNP edge and the probability of dog occurrences. From an ecological perspective, the presence of dogs inside the BNP indicates an edge effect. The occurrence of the maned wolf was positively associated with distance from a garbage dump site and negatively associated with the presence of dog tracks. The maned wolf and giant anteater seem to avoid areas near the garbage dump as well as areas with dog tracks. There is no support for the possible existence of a feral dog population inside the BNP, but the effects of free-ranging dogs on the wildlife population in such an isolated protected area must not be neglected. Domestic dog Canis familiaris populations and disease control programs should be established in the urban, sub-urban and rural areas surrounding the BNP, along with the complete removal of the garbage dump from the BNP surroundings.

Dogs threat to endangered huemul

From http://www.patagonjournal.com

Photo Paulo Corti

Patagonia's endangered huemul has its share of predators. Pumas, foxes, and the occasional poacher are expected, but a new threat has become a hounding concern in Chile's Aysen region. 

Dogs belonging to residents living near Lake Cochrane are killing young fawns, and injuring and sometimes killing adult huemul.

The huemul is a rare creature in the Patagonian landscape. An Andean deer that bears a strong resemblance to North American deer, the huemul (pronounced weh-MOOL) tends to live in much smaller groups. They are also docile creatures, a characteristic that may have sealed their fate.
“You can almost reach out and touch them,” says Paulo Corti, an animal ecologist and veterinarian at Chile's Austral University in Valdivia. He’s been tracking huemul populations since 2003 and estimates there are fewer than 2,000 left, living in 12 fragmented populations along the Argentine and Chilean slices of Patagonia, most of which live in Chile.
Since the arrival of Europeans in the 1500s, the huemul population has been in slow decline. Once abundant from central Chile to Tierra del Fuego, hunting initially cut huemul numbers in half. Now, the patchy Patagonian forests they inhabit are continually being cleared for tree farms, agriculture and development.
Though he is currently working on five ongoing studies throughout Patagonia, Corti's priority is a group of huemul in the Lake Cochrane National Reserve in southern Chile. In the past four years, this population has gone from 45 individuals down to around 30. Though his team can’t say with certainty if this decline is purely cyclical, they are especially worried right now about threats from dogs.
“The dogs attacking the huemul in the Lake Cochrane region are all from the town of Cochrane,” says Corti. “They’re dogs with first and last names.”
The small town of Cochrane sits on the two-laned Carretera Austral, or Southern Highway, at the foot of the steep hills of Lake Cochrane National Reserve. Most of the 3,000 residents raise sheep and cattle or farm crops.
Any visitor to Chile will report seeing vast numbers of dogs on streets, sometimes traveling in large packs. But curbing the numbers of street dogs, or wild dogs, in Chile is a contentious issue. Corti says they are untouchable and getting people to responsibly control their own dogs is a difficult challenge. “It’s a very long-term change. What we need is immediate change.”
In late September, huemul experts from Argentina and Chile convened in Valdivia, Chile, to make a comprehensive list of threats to the huemul’s survival. They suggested various techniques to slow the huemul’s decline, such as restoring and protecting more habitat, and improving connectivity between protected areas. The meeting led to the development of a formal “Binational Plan of Action for the Conservation of the Southern Huemul.”
But educating dog owners about their pets is surely one of the chief protection strategies. Says Corti: “Almost all of the dogs entering the reserve [near Cochrane] have owners, but Chileans are irresponsible with their mascots. Obviously, the dogs are hungry because their owners don’t feed them and let them freely roam.”

Dogs in gardens could benefit some indigenous birds

Daniels, G.D. & J.B. Kirkpatrick. 2006. Does variation in garden characteristics influence the conservation of birds in suburbia? Biological Conservation, 133: 326-335.

Can enhancement of garden habitat for native birds have conservation benefits, or are garden bird assemblages determined by landscape and environmental characteristics? The relative roles of vegetation structure, floristics and other garden attributes, and environmental and landscape controls, on the abundance and richness of bird species in 214 back or front gardens in 10 suburbs of Hobart, Tasmania, Australia, are addressed to answer this question. Birds were counted in each garden and the resources they utilized noted. Vascular plant species and other attributes of the garden were noted, along with rainfall, altitude, distance from natural vegetation, distance from the city and garden size. Garden floristics and bird assemblages were ordinated, and garden groups characterized by particular assemblages of birds identified. General linear modelling was used to determine the combinations of independent variables that best predicted the richness of birds and the abundance of individual bird species and groups of species. The models for bird richness, bird species and groups of bird species were highly individualistic. Although native birds showed a preference for native plants, they also utilized many exotic plants. Exotic birds largely utilized exotic plants. Variation in garden characteristics does substantially affect the nature of garden bird assemblages in Hobart, with weaker environmental and landscape influences. The fact that gardens can be designed and managed to favour particular species and species assemblages gives gardeners a potentially substantial role in the conservation of urban native avifauna.

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Human influence on the range of domestic cats in sensitive areas

Ferreira, J.P., Leitão, I., Santos-Reis, M. & Revilla E. 2011. Human-Related Factors Regulate the Spatial Ecology of Domestic Cats in Sensitive Areas for Conservation. PLoS ONE 6(10): e25970. doi:10.1371/journal.pone.0025970

Background

Domestic cats ranging freely in natural areas are a conservation concern due to competition, predation, disease transmission or hybridization with wildcats. In order to improve our ability to design effective control policies, we investigate the factors affecting their numbers and space use in natural areas of continental Europe.

Methodology/Principal Findings

We describe the patterns of cat presence, abundance and space use and analyse the associated environmental and human constraints in a well-preserved Mediterranean natural area with small scattered local farms. We failed in detecting cats in areas away from human settlements (trapping effort above 4000 trap-nights), while we captured 30 individuals near inhabited farms. We identified 130 cats, all of them in farms still in use by people (30% of 128 farms). All cats were free-ranging and very wary of people. The main factor explaining the presence of cats was the presence of people, while the number of cats per farm was mostly affected by the occasional food provisioning with human refuse and the presence of people. The home ranges of eight radio tagged cats were centred at inhabited farms. Males went furthest away from the farms during the mating season (3.8 km on average, maximum 6.3 km), using inhabited farms as stepping-stones in their mating displacements (2.2 km of maximum inter-farm distance moved). In their daily movements, cats notably avoided entering in areas with high fox density.

Conclusions

The presence, abundance and space use of cats were heavily dependent on human settlements. Any strategy aiming at reducing their impact in areas of conservation concern should aim at the presence of settlements and their spatial spread and avoid any access to human refuse. The movements of domestic cats would be limited in areas with large patches of natural vegetation providing good conditions for other carnivore mammals such as red foxes.

Leash regulations lack of impact on small vertebrates

Forrest, A. & C.C. St. Clair. 2006. Effects of dog leash laws and habitat type on avian and small mammal communities in urban parks. Urban Ecosystems, 9:51–66

Remnant natural areas within urban settings can act as important refuges for wildlife, substantially increasing local biodiversity. However, habitat suitability for these species is potentially affected by human recreational activities including the presence of free-running dogs. To compare the diversity and abundance of songbird and small mammal communities between areas with bylaws that require, or do not require, dogs to be leashed, point counts and live-trapping surveys were conducted in three habitat types (deciduous, coniferous, and meadow) in the river valley parks of Edmonton, Alberta. Among birds, there was no difference between areas with different leashing bylaws in species diversity for any of the three habitat types. Similarly, there was no difference in bird diversity for a subset of species that were plausibly breeding at these sites. However, higher bird diversity was recorded in deciduous and coniferous sites than in meadow sites, regardless of leash designation, probably as a function of the horticultural practice of mowing meadows. Among both birds and small mammals, there was no difference in the abundance of individuals as a function of leashing bylaws. Our results suggest that off-leash dogs have no effect on the diversity or abundance of birds and small mammals in urban parks, but it is also possible that other factors, such as leash law compliance, reduced or obscured the effects of off-leash dogs in this study.

Fearing the predator: Sublethal effects of cats

Bonnington, C., Gaston, K. J., Evans, K. L. (2013), Fearing the feline: domestic cats reduce avian fecundity through trait-mediated indirect effects that increase nest predation by other species. Journal of Applied Ecology, 50: 15–24.

Summary

Urban areas contain high densities of non-native species, which in the UK include the domestic cat Felis catus (Linnaeus 1758) and the grey squirrel Sciurus carolinensis (Gmelin 1788). The direct predation effects of domestic cats on prey populations attract intense debate, and such influences of the nest-predatory grey squirrel are receiving increasing attention. In contrast, theory predicts that sublethal and indirect effects are more important, but empirical evidence is currently lacking.

We conducted controlled model presentation experiments at active urban blackbird Turdus merula (Linnaeus 1758) nests to provide the first empirical evidence that quantifies the potential sublethal and indirect effects of predators (domestic cat and grey squirrel) on avian reproductive success.

Domestic cat models reduced subsequent parental provisioning rates, a strong indicator of sublethal effects, by one-third relative to a nonpredatory rabbit Oryctolagus cuniculus (Linnaeus 1758) control. There was no compensatory increase in food load size. Previous experiments demonstrate that this magnitude of reduced food delivery will reduce nestling growth rates by c. 40%. The grey squirrel model induced similar but weaker effects.

Following the brief presence of the domestic cat model, subsequent daily nest predation rates, chiefly by corvids, increased by an order of magnitude relative to the squirrel and rabbit models. The intensity of parental nest defence elicited in response to model presentations predicts the probability of such third-party predator predation events, and the domestic cat model generated significant increases in nest defence behaviour.

Synthesis and applications

The brief presence of a domestic cat at avian nest sites reduces subsequent provisioning rates and induces lethal trait-mediated indirect effects. We provide the first robust evidence for these latter effects in any avian predator–prey system, although they are likely to be common in many avian assemblages with high predator densities. It is imperative that future assessments of the impact of predatory species on avian prey species take lethal trait-mediated indirect effects into account, as so doing will prevent biased estimates of predator effects and facilitate the design of more effective control strategies. Full mitigation of the sublethal and indirect effects of domestic cats would problematically require permanent indoor housing.

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Disturbance of dogs to Wildlife

Lenth, B., R.L. Knight & M.E. Brennan. 2008. The Effects of Dogs on Wildlife Communities. Natural Areas Journal, 28 (3): 218-227

Domestic dogs (Canis familiaris) are frequent visitors to protected areas, but little is known about how they affect wildlife communities. We studied the effects of dogs on wildlife communities by comparing the activity levels of wildlife in areas that prohibited dogs with areas that allowed dogs. We measured wildlife activity on trails and up to 200 m away from trails using five methods: (1) pellet plots, (2) track plates, (3) remote triggered cameras, (4) on-trail scat surveys, and (5) mapping prairie dog (Cynomys ludovicianus) burrow locations. The presence of dogs along recreational trails correlated with altered patterns of habitat utilization by several species. Mule deer (Odocoileus hemionus) activity was significantly lower within 100 m of trails in areas that allowed dogs than in areas that prohibited dogs. Small mammals, including squirrels (Sciurus spp.) and rabbits (Sylvilagus spp.), also exhibited reduced levels of activity within 50 m of trails in areas that allowed dogs when compared with areas without. The density of prairie dog burrows was lower within 25 m of trails in areas that allowed dogs. The presence of dogs also affected carnivore activity. Bobcat (Felis rufus) detections were lower in areas that allowed dogs, and red fox (Vulpes vulpes) detections were higher. These findings have implications for the management of natural areas, particularly those that allow dogs to be off-leash.

Dog attacks to sheep

Jennens, G. 2002. Domestic dog attacks on sheep in the urban fringe areas of Perth, Western Australia. PhD thesis, Murdoch University.

In common with many cities, Perth, Western Australia has a problem with domestic dogs attacking livestock, such as sheep on its urban fringe areas. The current study used multiple sources to document 1479 attacks on livestock on 1105 properties by 1900 dogs across eight metropolitan local authorities over a three-year period. The hypothesis that dog attacks on sheep are poorly understood by the community and continue as a result of inaction by local authorities, dog owners and livestock owners, rather than being an unavoidable predator/prey interaction, was supported. The predatory behaviour of domestic dogs and the anti-predatory behaviour of sheep were observed to be similar to that of wild canids and ungulates respectively.

The reluctance of local authorities to prosecute offenders and enforce by-laws meant that there was little voluntary compliance by dog owners to control their dogs. It therefore, became necessary for livestock owners to protect their livestock; however, most failed to take effective preventive measures.

Wild canids predominantly attack the head and neck of prey animals, whereas in contrast, domestic dogs may attack any part of a sheep. Examination of injury sites, in conjunction with information collected from other investigative techniques, assisted with the identification of the breed, size and number of dogs responsible. To overcome difficulties in locating a dog not sighted attacking, tracker-dogs were trained to follow the attacker's scent back to its home. The majority of dogs (60%) lived within 200 metres of the livestock they attacked and used the same route to and from the property on subsequent attacks.

A single or pair of owned dogs from the same household, belonging to 14 breeds were primarily responsible for attacks. Poor management by dog owners on inadequately fenced smallholdings enabled these dogs to wander unnoticed from their properties. Although most dog owners accepted evidence of their dogs' involvement, few accepted blame and most were surprised that their "friendly" pet could attack livestock. Unless dogs were destroyed, relocated or contained by their owners they were likely to attack again.

It is concluded that dog attacks occur commonly in urban fringe areas; however, with appropriate management of dogs and livestock these can be minimised.

Impact of feral and free roaming dogs on Wildlife: review and study case in Mongolia

Young, J.K, K. A. Olson, R.P. Reading, S. Amgalanbaatar & J. Berger. 2011. Is Wildlife Going to the Dogs? Impacts of Feral and Free-roaming Dogs on Wildlife Populations. BioScience, 61(2):125-132.

In human-populated landscapes, dogs (Canis familiaris) are often the most abundant terrestrial carnivore. However, dogs can significantly disrupt or modify intact ecosystems well beyond the areas occupied by people. Few studies have directly quantified the environmental or economic effects of free-roaming and feral dogs. Here, we review wildlife-dog interactions and provide a case study that focuses on interactions documented from our research in Mongolia to underscore the need for studies designed to best determine how dogs affect native wildlife and especially imperiled populations. We suggest additional research, public awareness campaigns, and the exclusion of dogs from critical wildlife habitat. The application of scientific findings to management and enhanced public outreach programs will not only facilitate recovery and maintenance of wildlife populations globally but also has the potential to reduce economic losses.

A review of the interactions between free-roaming domestic dogs and wildlife

Hughes, J. & D.W. Macdonald. 2013. A review of the interactions between free-roaming domestic dogs and wildlife. Biological Conservation, 157: 341–351

Negative impacts from the presence of domestic animals pose particular issues for biodiversity conservation as they are intimately tied to the economic, social and political values of local people, requiring interdisciplinary cooperation for successful outcomes. Despite domestic dogs being widespread there is little information on the scale and scope of any conservation problems they may cause. Dog management is already carried out by human health and welfare groups in order to improve welfare and reduce disease spread, primarily rabies. By reviewing information about interactions between dogs and wildlife, this paper aims to provide a clear summary of current knowledge and facilitate interdisciplinary collaboration between conservation biologists and other experts.

Data from dog population and human population studies indicate that the global domestic dog population abundance is over 700 million. Studies on interactions between free-roaming dogs and wildlife were gathered from searches of seven online databases and other sources. In total, 69 peer-reviewed studies were found. The wildlife taxon mainly studied was mammals (78%) and the main interaction recorded was predation by domestic dogs, followed by disease transmission, wildlife disturbance, hybridization and predation of dogs by wild carnivores. Conservation issues with domestic dogs were recorded from around the world, both on islands and continents. Suggestions of solutions were limited, or not offered, beyond extermination which, given the close relationship between local people and dogs, may not often be appropriate. We propose some steps that will aid cooperation between conservationists and other sectors and enhance the effectiveness of conservation activities.

Highlights

► Domestic dogs Canis familiaris are a globally abundant domestic carnivore.
► We review documented interactions between wildlife and free-roaming domestic dogs.
► Globally, free-roaming dogs cause issues for species conservation and human health.
► Dogs negatively interact with wildlife, mainly by predation and disease spread.
► Interdisciplinary collaboration between experts is needed for effective solutions.

Disturbance from dogs or from people?

Reed, S. & A.D. Merenlender. 2011. Effects of Management of Domestic Dogs and Recreation on Carnivores in Protected Areas in Northern California. Conservation Biology, 25(3):504-513

In developed countries dogs (Canis lupus familiaris) are permitted to accompany human visitors to many protected areas (e.g., >96% of protected lands in California, U.S.A.), and protected-area management often focuses on regulating dogs due to concerns about predation, competition, or transmission of disease and conflicts with human visitors. In 2004 and 2005, we investigated whether carnivore species richness and abundance were associated with management of domestic dogs and recreational visitation in protected areas in northern California. We surveyed for mammalian carnivores and human visitors in 21 recreation areas in which dogs were allowed offleash or onleash or were excluded, and we compared our observations in the recreation areas with observations in seven reference sites that were not open to the public. Carnivore abundance and species richness did not differ among the three types of recreation areas, but native carnivore species richness was 1.7 times greater (p < 0.01) and the relative abundances of native coyotes (Canis latrans) and bobcats ( Lynx rufus) were over four times greater (p < 0.01) in the reference sites. Abundances of bobcats and all carnivores declined as the number of visitors increased. The policy on domestic dogs did not appear to affect species richness and abundance of mammalian carnivores. But the number of dogs we observed was strongly associated with human visitation (R²= 0.54), so the key factors associated with recreational effects on carnivores appear to be the presence and number of human visitors to protected areas.