Livestock loss caused by predators outside the Serengeti National Park, Tanzania

Human-carnivore conflict is a serious management issue often causing opposition towards conservation efforts. In a survey of 481 households in seven different villages outside the Serengeti National Park in Tanzania, 67.4% of respondents owned livestock and 27.4% of all the households surveyed reported losses of a total of 4.5% of their livestock to wild predators over 12 months. This loss equated to an average annual financial loss of 19.2% (US $26.8) of their cash income. Livestock depredation was reported to be caused most often by spotted hyena (Crocuta crocuta) (97.7%), leopard (Panthera pardus) (1.6%), baboon (Papio cynocephalus) (0.4%), lion (Panthera leo) (0.1%) and lastly black-backed jackal (Canis mesomelas) (0.1%). Total reported losses during 2003 amounted to US $12,846 of which spotted hyena kills were reported to account for 98.2%. The mean annual livestock loss per household (of those that reported loss) was 5.3 head of stock, which represents more than two-thirds of the local average annual cash income. Depredation by large felids occurred only in a narrow zone along the protected area (<3 km), whereas spotted hyenas killed livestock even in households located far away (>30 km). Tolerance of livestock depredation among the respondents was low. Logistic regression models indicated that education improved tolerance, while for livestock owners higher depredation rates was linked to approval of lethal retaliation and effective protection measures was associated with a reduced desire of retaliation. We recommend that further research should identify the precise causes of livestock loss and which protection measures that can reduce depredation.     

Mountain lion depredation in southern Brazil

Mountain lion (Puma concolor) depredation incidents on livestock herds were recorded at 15 ranches in southern Brazil from 1993 to 1995. Maximum losses to mountain lions were 78% for goats, 84% for sheep, and 16% for cattle. Cattle mortality arising from causes other than depredation assumed a greater importance in herd productivity. In contrast, attacks on sheep and goats were more frequent than losses to other causes, but could be reduced to acceptable levels when flocks were corralled at night. Most depredation incidents occurred when weather and light conditions were unfavorable to human activity. We explain these patterns and inter-ranch variation in depredation rates on the basis of a risk-avoidance strategy by the mountain lions. Stock losses can be minimized by understanding these patterns and by applying appropriate herd husbandry, thus reducing the urge to persecute this protected species.     

Farmer attitudes toward wolves: Implications for the role of predators in managing disease

The potential for disease transmission between wild and domestic animals may interfere with wildlife and habitat conservation on lands surrounding protected areas. Recently, possible transmission of bovine tuberculosis (Mycobacterium bovis) from wild ungulates to domestic livestock has affected the Riding Mountain National Park region in Manitoba, Canada. Wolf (Canis lupus) predation on ungulate populations may help lessen the risk of disease transmission to livestock. We conducted an exploratory analysis of causal factors associated with farmer attitudes toward observing wolves on their farms. A survey to 4 220 farms within 50 km of the Park resulted in an adjusted response rate of 25%. We constructed several logistic regression models with factors hypothesized to influence whether farmers agreed with the statement “I enjoy seeing wolves on my land”, and three candidate models received reasonable support. Factors most affecting attitudes were, in order of importance, perceived wolf population size, frequency of seeing wolves, perceived seriousness of wolf damage, distance to Park boundary and number of beef cattle (Bos taurus) owned. The factors least influential on attitudes were education and age. Concern over bovine tuberculosis in wild elk also had minimal influence. Of respondents who perceived the wolf population as “too high”, 60% were extremely concerned about bovine tuberculosis in wild elk. Although the role of wolf predation as a potential natural regulator of disease in wild ungulates might not be widely recognized in many areas, we believe this provides a unique opportunity to re-examine the significance of maintaining viable wolf populations.     

Evaluation of a compensation scheme to bring about pastoralist tolerance of lions

Lions (Panthera leo) are in decline throughout most of their range due to human persecution, largely provoked by depredation on livestock, and there is debate as to the usefulness of financial instruments to mitigate this conflict. Intending to reduce local lion-killing, the Mbirikani Predator Compensation Fund compensates members of Mbirikani Group Ranch for livestock depredation at a flat rate (close to average market value), after the kill has been verified and with penalties imposed for poor husbandry. Despite penalizing claimants, 55% of claims arose because livestock were lost in the bush. Between 1st April 2003 and 31st December 2006, 754 cattle, 80 donkeys and 1844 sheep/goats were killed (2.31% of the total livestock herd each year). Forty-three percent of kills were ascribed to spotted hyaenas (Crocuta crocuta); leopards (Panthera pardus) and cheetahs (Acinonyx jubatus) were blamed for 37% of cases, lions 7%, jackals (Canis mesomelas) 7% and buffalo (Syncerus caffer) and elephants (Loxodonta africana) together 6%. Significantly more attacks took place during months of lower rainfall but the rate of attacks was not related to the density of livestock on the ranch, or the ratio of wild herbivores to domestic stock. There was no correlation between local market prices and the number of claims per month. Despite compensation, at least one lion per year was killed in 2004, 2005 and 2006. We describe some features of large carnivore depredation in the study area and suggest that regional recovery of the lion population may require compensation on a wider scale.     

Jaguars, pumas, their prey base, and cattle ranching: ecological interpretations of a management problem

Jaguar and puma depredation on livestock may be influenced by (1) innate and learned behavior; (2) health and status of individual cats; (3) division of space and resources among jaguar and puma; (4) cattle husbandry practices; and (5) abundance and distribution of natural prey. Our study in Los Llanos of Venezuela aimed to establish how all these elements related to cattle being lost to cat depredation. Prey distribution was influenced by forest composition, topographical characteristics, and degree of habitat interspersion. The biomass of natural prey in the study area was adequate to support the resident large cats without a subsidy of livestock. Selective rather than opportunistic hunting by the cats reinforced that conclusion. Puma were responsible for more attacks on livestock than jaguar, frequently in maternity pastures in upland areas of relatively low prey availability. Management recommendations are discussed that may be relevant to other savanna/forest mosaics of South America.     

The potential contribution of ecotourism to African wild dog Lycaon pictus conservation in South Africa

African wild dogs are endangered, and in South Africa as elsewhere, they inhabit a fraction of their former range. In this study, we assessed the potential for economic benefits derived from ecotourism to offset the costs of three wild dog conservation options using a contingent valuation study of the willingness of visitors to four protected areas to pay to see wild dogs at the den - within a viable population in a large protected area (Kruger National Park), through reintroduction into nature reserves, and through the conservation of wild dogs occurring on ranchland in situ. Results indicated that tourism revenue from wild dogs in large protected areas is more than sufficient to offset the costs and could potentially be used to subsidise wild dog reintroductions or the conservation of wild dogs in situ on ranchland. On ranchland and for reintroductions, tourism revenue was generally predicted to offset most of the costs of conserving wild dogs where predation costs are low, and to exceed the costs where willingness to pay is high, and/or where the costs of predation by wild dogs are zero. Conservation efforts should facilitate the derivation of eco-tourism-related benefits from wild dogs on ranchland and in private reserves to create incentives for wild dog conservation. Ecotourism should be part of a multifaceted approach to wild dog conservation which also includes education and awareness campaigns, and efforts to encourage landowners to cooperate to form conservancies.     

Spatial, temporal, and physical characteristics of livestock depredations by large carnivores along a Kenyan reserve border

Most large mammalian carnivores are in global decline, largely due to their involvement in livestock depredation. Research that advances our understanding of predator-livestock interactions is crucial to conflict mitigation and carnivore conservation. Here we investigated the influence of environmental and socio-ecological factors on livestock depredation by carnivores in pastoral villages adjacent to the Maasai Mara National Reserve, Kenya during a 14-month period. We attempted to identify factors associated with temporal and spatial variation in depredation rates, incorporating data on a closely monitored spotted hyena (Crocuta crocuta) population known to be involved in depredation events. Spotted hyenas, leopards (Panthera pardus) and lions (Panthera leo) were responsible for 53%, 32%, and 15% of attacks on livestock, respectively. Monthly depredation frequency was correlated positively with rainfall and negatively with natural prey abundance. Radio-telemetry revealed that hyenas defending a group territory within the Reserve spent more time outside the Reserve during months when hyena attacks on livestock were most frequent. Results of logistic regression models, which indicated spotted hyenas were most likely to attack large villages, were supported by behavioral observations of hyenas near villages. Leopards however, selected villages that were spatially isolated from other villages. Hyenas were more likely to attack livestock enclosures constructed of local bush material than those of more sturdy “pole” timber, but use of pole material more than doubled the probability of leopard attack. Selection of fence type should therefore depend on the size and relative isolation of villages. Overall, improved fences, more watch dogs, and high levels of human activity were not associated with lower livestock losses to predators.     

Spatial organization and food habits of jaguars (Panthera onca) in a floodplain forest

For most carnivore populations, territoriality is the regulating social system ultimately determined by food abundance and/or strife. However, in some food-based territorial felid species such as the jaguar (Panthera onca), the influence of food availability on territoriality remains unclear and may be lessened because of a tendency for individuals to occur at high densities across the landscape. We examined spatial organization and use of food in a population of jaguars in the southern region of the Pantanal, Brazil (2003-04). We predicted that if territoriality plays an important role in determining jaguar population dynamics, exclusive use of territories should be observed and thereby influence prey selection patterns. We determined that home range sizes were comparable between sexes and overlapped little at the core area level. Line transect surveys revealed that large mammals comprised the bulk of available wild prey for jaguars, and scat analysis indicated that jaguars relied mostly on large mammalian prey. The most common wild species killed by jaguars were capybara (Hydrochaeris hydrochaeris) and caiman (Caiman yacare). We estimated that the wild prey base was adequate to support the jaguar population. Larger wild prey species were considerably more likely to die from predation than from other causes, and predation was more likely to occur in jaguar core areas than in areas of home range overlap. Modest cattle depredation rates had little demographic importance to the local jaguar population. We conclude that spacing patterns in the local jaguar population were likely based on exclusion through territoriality rather than food limitation.     

Connectivity of the Asiatic wild ass population in the Mongolian Gobi

Long-distance migrations of wildlife have been identified as important biological phenomena, but their conservation remains a major challenge. The Mongolian Gobi is one of the last refuges for the Asiatic wild ass (Equus hemionus) and other threatened migratory mammals. Using historic and current distribution ranges, population genetics, and telemetry data we assessed the connectivity of the wild ass population in the context of natural and anthropogenic landscape features and the existing network of protected areas. In the Mongolian Gobi mean biomass production is highly correlated with human and livestock density and seems to predict wild ass occurrence at the upper level. The current wild ass distribution range largely falls into areas below the 250 gC/m²/year productivity isoline, suggesting that under the present land use more productive areas have become unavailable for wild asses. Population genetics results identified two subpopulations and delineated a genetic boundary between the Dzungarian and Transaltai Gobi for which the most likely explanation are the mountain ranges separating the two areas. Home ranges and locations of 19 radiomarked wild asses support the assumed restricting effects of more productive habitats and mountain ranges and additionally point towards a barrier effect of fences. Furthermore, telemetry data shows that in the Dzungarian and Transaltai Gobi individual wild ass rarely ventured outside of the protected areas, whereas in the southeast Gobi asses only spend a small fraction of their time within the protected area network. Conserving the continuity of the wild ass population will need a landscape level approach, also including multi-use landscapes outside of protected areas, particularly in the southeast Gobi. In the southwest Gobi, allowing for openings in the border fence to China and managing the border area as an ecological corridor would connect three large protected areas together covering over 70,000 km² of wild ass habitat.     

Impacts of livestock in regenerating upland birch woodlands in Scotland

Including large herbivores in wooded areas is often seen as a useful conservation tool. Browsing intensities on saplings in seven upland birch woodlands grazed by sheep, cattle and wild herbivores were studied. The aims were to determine whether tree regeneration could occur in the presence of livestock, particularly sheep, and the conditions under which stock can be grazed sustainably within woodlands.The results showed that regeneration can occur at sites grazed by livestock. Within-site variation in the proportion of shoots browsed per sapling was high, but significant trends were detected. Browsing intensity was negatively related to good quality biomass per livestock unit, basal diameter and adjacent vegetation height. Saplings with a topiaried growth form were browsed more than saplings with a normal growth form.When writing management plans, stocking densities should be set in relation to forage quantity and quality. Understanding the relationship between good quality biomass per livestock unit and browsing intensity will facilitate more sustainable management of grazing within woodlands.     

Livestock predation by carnivores in Jigme Singye Wangchuck National Park, Bhutan

Villages in Jigme Singye Wangchuck National Park, central Bhutan, report livestock depredation by wild carnivores including leopard (Panthera pardus), tiger (Panthera tigris), Himalayan black bear (Ursus thibettanus), and dhole (Cuon alpinus). In a survey of 274 households in six different geogs (sub-districts) within the park, 21.2% of households surveyed reported losses of a total of 2.3% of their domestic animals to wild predators over 12 months. This loss equated to an average annual financial loss equal to 17% (US$ 44.72) of their total per-capita cash income. Total reported losses during 2000 amounted to US$ 12,252, of which leopard and tiger kills accounted for 82% (US$ 10,047). Annual mean livestock loss per household (of those that reported loss) was 1.29 head of stock, equating to more than two-thirds of their annual cash income of $250. Lax herding, inadequate guarding practices, and overgrazing may have contributed to livestock losses. Approximately 60% of the households lacked proper stables for corralling their livestock at night and there was a significant correlation between the number of livestock lost and the distance between the household and the grazing pasture. Overall, reported predation rates have increased since the inception of the park in 1993 and since implementation of the Forest and Nature Conservation Act in 1995, which prioritises some of Bhutan’s key livestock predators for conservation. We propose livestock intensification programmes, including pasture improvement, and financial compensation as short-term measures to reduce conflict between people and predators. In the long-term, we recommend that the feasibility of an insurance scheme should be tested, the possibility of relaxing the resource use restrictions in the Forest and Nature Conservation Act of 1995 be explored, and that farmers should be involved in managing human-wildlife conflicts - particularly through improving their own herding and guarding practices, and building proper corralling facilities and adopting reliable corralling procedures.     

Factors affecting Eurasian lynx kill rates on semi-domestic reindeer in northern Scandinavia: Can ecological research contribute to the development of a fair compensation system?

Semi-domestic reindeer (Rangifer tarandus) are the main prey for lynx (Lynx lynx) in northern Scandinavia. This causes large, but poorly documented, losses of reindeer. Although the compensation schemes differ between Norway and Sweden, there is a legal requirement in both Scandinavian countries that losses of semi-domestic reindeer to large carnivores should be fully compensated. The current level of compensation payment is based on limited data on lynx kill rates on reindeer. The main goal of this study was to quantify lynx kill rates on reindeer across a range of ecological conditions in northern Scandinavia. A total of 35 lynx were monitored during 3667 days. All lynx individuals killed reindeer. However, we observed a high variation in individual kill rates. Kill rates were strongly affected by sex and social status (i.e. females with and without kittens), as well as season and reindeer availability. The highest kill rates were observed in summer for male lynx, and the lowest were observed during winter for solitary lynx at low reindeer density. In summer, several female lynx switched completely to small prey species even at high densities of reindeer. The present political goals for lynx conservation in Scandinavia require that lynx occur in the reindeer husbandry area where reindeer are the only suitable ungulate prey available. Accordingly, it is therefore impossible to have the total prevention of depredation as a management goal. Rather depredation levels must be limited such that they are considered acceptable, and fair compensation payments should be paid. Our study is the first empirical quantification of the magnitude of lynx depredation on semi-domestic reindeer. This is an important step necessary to enable the setting of fair compensation levels and will hopefully lead to a reduction in conflict level concerning the potential impacts that lynx have on reindeer.     

The influence of food availability on breeding success of African penguins Spheniscus demersus at Robben Island, South Africa

From 1989 to 2004, the breeding success of African penguins Spheniscus demersus at Robben Island, South Africa was significantly related to estimates of the abundance of both their main prey species, anchovy Engraulis encrasicolus and sardine Sardinops sagax, and to the combined biomass of these species. When the combined spawner biomass of fish prey was less than 2 million ton, pairs fledged an average of 0.46 chicks annually. When it was above 2 million ton, annual breeding success had a mean value of 0.73 chicks per pair. Given previously estimated values of survival and age at first breeding, these levels of breeding success are inadequate to sustain the African penguin population. With the higher level of breeding success, an equilibrium situation might be attained if adult survival could be increased by 6-7% per annum. Attempts to reduce mortality of penguins have included the collection, cleaning and return to the wild of oiled birds, culling of Cape fur seals Arctocephalus pusillus pusillus seen preying on penguins around breeding localities and control of the spread of disease. Management of the purse-seine fishery should ensure adequate escapement of fish to maintain the combined biomass of anchovy and sardine above 2 million ton. The maintenance of suitable breeding habitat and removal of feral predators from breeding localities will also be important in improving breeding success.     

Conflicts between Amur (Siberian) tigers and humans in the Russian Far East

In 1999, the Russian Federation created a Tiger Response Team (TRT) to investigate and intervene in human–tiger conflicts. We examined data collected on human-Amur tiger (Panthera tigris altaica) conflicts from January 2000 through February 2009 to: (1) summarize and characterize human–tiger conflicts in the area, (2) examine causes of human–tiger conflicts, and (3) attempt to evaluate the effectiveness of the TRT. The team investigated 202 conflicts. Both attacks on humans and depredations were greatest in winter (X² = 9, df = 3, P = 0.03 and X² = 64, df = 3, P < 0.001, respectively). Tiger depredation on domestic animals was the most common type of conflict reported (57%), followed by tigers near human habitations (22%), miscellaneous conflicts (12%), and attacks on humans (9%). Dogs were killed more commonly than other domestic animals (63% of 254 animals), likely because livestock were well managed. Nineteen attacks on humans were recorded resulting in 11 injuries and 2 deaths. Nearly four tigers per year (n = 32 tigers) died, were killed, or were removed from the wild, and all but 1 of 20 tigers killed or removed from the wild by the TRT were considered unfit to survive in the wild. Attacks on humans (n = 19) were most often (77%) by wounded tigers (80% of injuries were human-caused) and commonly provoked (47% of attacks). The effectiveness of interventions focused on reducing depredation on domestic animals was unclear, but data suggested that removal of injured and other unhealthy tigers from the wild by the Tiger Response Team resulted in fewer human deaths. Our recommendations include that the TRT continues to work to reduce conflict by rapidly removing debilitated tigers from the wild, explores different methods and technologies for reducing depredation on domestic animals, and increases their efforts to maintain tigers in the wild through telemetry monitoring, translocation, and rehabilitation of orphaned cubs. Further, standardized data should be collected to evaluate all interventions, with information from evaluation guiding an adaptive management component of their human–tiger conflict mitigation activities. This process should occur across tiger landscapes in Asia to allow rapid assessment of interventions.     

Lions and Warriors: Social factors underlying declining African lion populations and the effect of incentive-based management in Kenya

African lion (Panthera leo) populations are in decline throughout most of Africa, but the problem is particularly acute in southern Kenya, where Maasai people are spearing and poisoning lions at a rate that will ensure near term local extinction. Lion killing is shaped by Maasai perception of livestock depredation, socio-economic factors, and the complex relationship between Maasai and conservation. These all affect tolerance for lions and consequently Maasai behavior towards conservation initiatives and carnivores in general. We used an in-depth quantitative questionnaire and participatory rural appraisals (PRAs) to identify the social and ecological predictors of lion killing and to investigate the effect of a compensation scheme on individual tolerance. Individuals who lose a greater proportion of their livestock to predators relative to their overall livestock loss, those affiliated with an evangelical church, and those who mainly sell rather than accumulate livestock all reported a higher propensity to kill carnivores. The future of carnivore conservation in this region depends on a better understanding of the nuances of human–carnivore conflict and a concerted effort to address appropriate cultural and community-level institutions, chiefly by providing economic benefits to local people who engage in positive conservation activities.     

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

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.     

Getting to grips with the magnitude of exploitation: Bushmeat in the Cross-Sanaga rivers region, Nigeria and Cameroon

Wild meat harvests in African moist forests are presumed to exceed production, even in the case of traditional societies still using rudimentary hunting methods. Though some approximations do exist of the volume of bushmeat harvested in some Central African moist forest areas, estimates based on extensive and simultaneous sampling, within a large geographical region, are not available. Here, we present the results of the first reported study of this kind. During a period of 5 month, we counted bushmeat carcasses deposited in 89 urban and rural markets in a 35,000 km² area between the Cross River in Nigeria and the Sanaga River in Cameroon. We used these data to calculate annual bushmeat volume traded by site, species and overall in the study area.Mammals represented >90% of the bushmeat carcasses sold in all sites. Reptiles were also abundant, but birds and amphibians were relatively scarce. Estimates of carcasses extracted and crude biomass per site varied significantly between countries. In Nigeria, biomass (kg) extracted for sale per km² per year, was three times greater (600 kg/km²) than in Cameroon. Conservative estimates for the entire study area indicate that >900,000 reptiles, birds and mammals are sold each year by the rural and urban population, corresponding to around 12,000 tonnes of terrestrial vertebrates. We also assessed the relationship between bushmeat harvested for sale and distance of the study settlements from the main protected areas (Cross River and Korup National Parks). The number of carcasses and biomass sold was negatively related to the proximity to the national parks in >50% of species in Nigeria, and in 40% of species in Cameroon.Our cross-site comparison documents the staggering volume of wild species affected by hunting in the region. We also conclude that species within the main protected areas in both countries are likely to be negatively affected by the current and future demand for bushmeat in the surrounding areas.     

Dogs on the catwalk: Modelling re-introduction and translocation of endangered wild dogs in South Africa

In South Africa, a plan was launched to manage separate sub-populations of endangered African wild dogs (Lycaon pictus) in several small, geographically isolated conservation areas as a single meta-population. This intensive management approach involves the re-introduction of wild dogs into suitable conservation areas and periodic translocations among them. Despite the initial failures and high costs associated with wild dog re-introductions and translocations, there is no predictive framework available to quantify which management protocol is the most efficient. We therefore developed an individual-based model of wild dog population and pack dynamics, which accounts for the wild dogs’ social complexity. The model appeared to capture the essential characteristics of a real wild dog population from Hluhluwe-iMfolozi Park, South Africa and to be relatively robust to parameter uncertainty, suggesting that the model is valid enough for addressing management problems. The model enabled us to quantify a critical initial number of packs (two) and individuals per pack (six) necessary for a re-introduced wild dog population to establish itself in the release area. We also found a practically feasible intervention regime at which a re-introduced wild dog population had the best chance of persistence: intermittently adding packs (at least every 6 years) and harvesting disperser groups (as often as every 4 years) for translocation to other release sites, without threatening the small source population. This study demonstrates that individual-based models can be a powerful decision-support tool in re-introduction planning and provides insight into how populations made up of social groups have dynamics, and ultimately persistence, determined by individual behaviour.     

Predator-prey relationships and responses of ungulates and their predators to the establishment of protected areas: A case study of tigers, leopards and their prey in Bardia National Park, Nepal

Interactions among sympatric large predators and their prey and how they respond to conservation measures are poorly known. This study examines predictions concerning the effects of establishing a protected area in Nepal on tigers (Panthera tigris), leopards (Panthera pardus), and their ungulate prey. Within a part of the park, after 22 years the total density of wild ungulates had increased fourfold, to ca. 200 animals/km², almost exclusively due to a remarkable increase in chital deer (Axis axis). Tiger density also increased markedly to nearly 20 animals/100 km², whereas leopard density did not and was ca. 5 animals/100 km². The prediction that grazers should increase more than browsers was only partially supported. The prediction of positive density dependence in prey selection was not supported. Instead, the most abundant species (chital and hog deer, Axis porcinus) were killed less frequently than expected, whereas the lower-density wild boar (Sus scrofa) was preferred. Predictions that (i) initially rare species suffer highest predation was partially supported, that (ii) predation is highest among the most abundant prey was not supported, and that (iii) predation is highest among the most preferred prey independently of their densities was supported. Clearly, the conservation efforts adopted in Bardia were successful, as both tigers and their natural prey base increased. However, the positive numerical response of tigers limited and depressed the abundance of some prey species. Thus, conservation activities aimed at restoring large predators are likely to change in the composition of the overall mammal community, potentially eliminating rare but preferred prey species.     

Barn owl release in lowland southern England—a twenty-one year study

Twenty-one years of carefully documented barn owl (Tyto alba) study and release in England by the South Midlands Barn Owl Conservation Group (SMBOCG) have necessitated a re-examination of some of the premises on which such release schemes are judged. Fifteen years after the first releases, the number of independently breeding owls (i.e. breeding ‘wild’ or ‘as though wild’) in a 1200 km² study area is still increasing sharply and now far exceeds the number released in any one year, with the rate of increase outstripping the cumulative number of release events. Ringing returns indicate that fledged young dispersed further than adults, and that released adults which immediately deserted their release sites were less likely to survive their first 30 days than those staying in the vicinity of their release, where they could take advantage of supplementary feeding. Artificial feeding at release sites led to pellets containing lower liveweight equivalent of wild-caught prey but higher numbers of fledged young. Otherwise, and importantly, no significant difference in survival, mortality, dispersal, foraging success or breeding success was found between wild/independent owls and various categories of released bird. Availability of field vole habitat was not as important for barn owl breeding success as was found in previous studies, with owls able to replace this species in their diet with the less habitat-specific wood mouse. Evidence is provided that starvation was not as important a cause of mortality as has been proved elsewhere. Although barn owl nests often occurred in extreme close proximity, breeding density had no effect on either foraging or breeding success. The possible genetic consequences of barn owl release in Britain are briefly discussed. Very few barn owl release schemes have attempted to prove that their work is worthwhile, so long-term, well-documented studies such as that presented here are vital in establishing some of the principles involved in releasing barn owls into the wild.