Context . Worldwide, invasive fauna species present one of the most intractable problems for agriculture and natural systems. Our ability to improve control techniques to combat the global invasive species predicament is constrained within the bounds of both economic and ethical considerations. In south-eastern Australia, the common starling (Sturnus vulgaris) is an established invasive avian pest that is now making incursions into areas of Western Australia (WA) that are currently free of this species. The most cost-effective and widely implemented starling control tool is trapping with live-lure birds. In recent years, the use of live-lure birds has been questioned on both economic and ethical grounds, and consequently alternative lure methods need investigating.

Aims . To evaluate the effectiveness of different trap and lure combinations for the capture of starlings in western South Australia (SA).

Methods . Modified Australian Crow (MAC) traps, used traditionally in WA to trap starlings, and Myna traps, originally designed for trapping common mynas (Sturnus tristis), were set during the peaks in starling flocking activity (Austral summer, 2007) using three different lure types: (1) live lure (live starlings); (2) moving water; and (3) acoustic lures. A trapping grid consisting of a single Myna trap with live lure and three MAC traps, each with one type of lure (live, water or acoustic) was established at five sites on the Eyre Peninsula in SA and monitored twice daily for 28 days.

Key results . Live lures were significantly more effective at attracting starlings into traps compared with both water and sound lures. We also trapped at an additional three sites and showed that Myna traps caught ∼1.5 times more starlings than MAC traps when both traps were fitted with live-lure birds.

Conclusions . Neither moving water nor acoustic play-back lures proved suitable replacements for the use of live-lure birds to capture starlings. The efficacy of alternative lure types may depend on several factors and may include neophobic response(s) to novel signals and also the length of time that an invasive population has been established.

Implications . We recommend that use of live lures is continued in ongoing starling control programs, and that MAC traps currently in use be modified to capitalise on known starling behaviour. Further research and development of traps that do not contain live lures will improve the welfare of invasive species control programs.

Context. Exclosure fences are widely used to reintroduce locally extinct animals. These fences function either as permanent landscape-scale areas free from most predators, or as small-scale temporary acclimatisation areas for newly translocated individuals to be ‘soft released’ into the wider landscape. Existing research can help managers identify the best design for their exclosure fence, but there are currently no methods available to help identify the optimal location for these exclosures in the local landscape (e.g. within a property).

Aims. We outline a flexible decision-support tool that can help managers choose the best location for a proposed exclosure fence. We applied this method to choose the site of a predator-exclusion fence within the proposed Lorna Glen (Matuwa) Conservation Park in the rangelands of central Western Australia.

Methods. The decision was subject to a set of economic, ecological and political constraints that were applied sequentially. The final exclosure fence location, chosen from among those sites that satisfied the constraints, optimised conservation outcomes by maximising the area enclosed.

Key results From a prohibitively large set of potential exclosure locations, the series of constraints reduced the number of candidates down to 32. When ranked by the total area enclosed, one exclosure location was clearly superior.

Conclusions. By describing the decision-making process explicitly and quantitatively, and systematically considering each of the candidate solutions, our approach identifies an efficient exclosure fence location via a repeatable and transparent process.

Implications. The construction of an exclusion fence is an expensive management option, and therefore needs to convincingly demonstrate a high expected return-on-investment. A systematic approach for choosing the location of an exclosure fence provides managers with a decision that can be justified to funding sources and stakeholders.

Context. In many parts of the world, brown rats have colonised sewer systems and the rat populations in sewers are often thought to be a source of problems with rats on the surface. The management of sewer rat populations is usually performed with little, if any, knowledge of the dynamics and behaviour of these populations.

Aims. The study aimed to uncover the population dynamics, movements and distribution of rats in populations living in sewers.

Methods. We studied rats in a capture–mark–recapture study in two adjacent but separate sewer systems in suburban Copenhagen, Denmark, covering a surface area of 30 Ha. Multiple-capture live traps were placed in manholes in public sewers; animals were marked individually and data were collected every fourth week for a period of almost 3 years.

Key results. In total, 332 individual rats were trapped. Approximately one-third were only caught once, half of these were juveniles. The median time an individual was present in the sewers was 4 months with maxima up to 22 months. Abundance ranged from 2 to 44 animals per sewer system and the dynamics showed no regular fluctuations. Rats were distributed throughout the study area, regardless of sewer dimensions. Juvenile rats were captured more in the smaller and drier sewer sections. Activity areas of rats of both sexes overlapped partially, and observations of bite wounds were rare, suggesting a high degree of tolerance. The average maximal distance covered by rats was ∼200 m for both sexes. Day-to-day movements took place over shorter distances. There were no movements of rats between sewer systems and no sewer rats were observed to be active on the surface. The rat populations seemed to be substructured in smaller groups.

Conclusions. Sewer rat populations vary irregularly in abundance. Pipe dimensions are not important for the presence of rats but breeding seems concentrated in smaller and drier pipes. Most individuals are resident and live in small groups that are active in a limited area only, but still there is a fair group of dispersing rats.

Implications. Sewer rat management should be spread out spatially in a sewer system since most rats move over short areas only. Recolonisation by dispersing rats must be taken into account if sewer systems are connected. It is likely that targeting smaller and drier pipes will affect reproductive success.

Context. Wild predators are a serious threat to livestock in Australia. Livestock guardian dogs (LGDs) may be able to reduce or eliminate predation, but their effectiveness in Australian grazing systems has not been systematically evaluated. In particular, little is known about the effectiveness of LGDs in situations where they range freely over large areas in company with large numbers of livestock.

Aims. We aimed to evaluate the effectiveness of LGDs as currently used in Australia and determine the factors influencing effectiveness, in particular in relation to scale of management. We also documented how LGDs are managed in Australia, evaluated their cost effectiveness, and identified factors that influence the number of dogs required in different property situations.

Methods. We conducted a telephone survey of 150 livestock producers with LGDs in Australia, including all livestock types and property situations, in all States. Ten producers were visited, of which one is detailed as a case study.

Key results. Effectiveness was apparently high: 65.7% of respondents reported that predation ceased after obtaining LGDs, and a further 30.2% reported a decrease of predation. When the number of stock per dog exceeds 100, LGDs might not be able to eliminate all predation. Dogs are often kept free-ranging on large properties where wild dogs are the main predator, but are usually restricted in their movements on smaller properties or with smaller predators. The cost of obtaining a LGD is returned within 1–3 years after the dog starts working. The number of dogs required for a property mainly depends on the number of livestock needing protection, and the main type of predator in the area.

Conclusions. Provided a sufficient number of LGDs are used, they can be as effective in protecting livestock from predators in Australia when ranging freely on large properties with large numbers of livestock as they are in small-scale farming systems.

Implications. LGDs can provide a cost-effective alternative to conventional predator control methods in Australia’s extensive grazing enterprises, potentially reducing or eliminating the need for other forms of control. LGDs could play a major role in securing the viability of livestock businesses and reconciling people–predator conflict in Australia.

Context. It is difficult to determine with accuracy the nutrition of bird diets through observation and analysis of dietary items. Collection of the ingested material from the birds provides an alternative but it is often limited by the small sizes of samples that can be obtained.

Aims. We tested the efficacy of near-infrared reflectance spectroscopy (NIRS) to assess the nutritional composition of very small samples of growing-parrot crop content.

Methods. We used 30 samples of the crop content of free-living scarlet macaw (Ara macao) chicks. Samples were scanned with a near-infrared reflectance analyser, and later analysed by traditional wet laboratory methods for crude protein/N, fat, ash, neutral detergent fibre, P, K, Ca, Mg, Cu, Zn and S. A calibration model was developed using principal components analysis.

Key results. Coefficients of determination in the calibration (R²) and standard errors of cross-validation (SECV) for most of the nutrients showed a good performance (mean R² of 0.91 ± 0.11 s.d., n = 10) when excluding Zn (R² of 0.15, SECV = 25.37).

Conclusions The present results established NIRS as a valid technique for the non-destructive, low-cost prediction of a variety of nutritional attributes of avian crop contents as small as 0.5-g dry weight.

Implications. The use of NIRS expands the possibilities of wild-animal nutrition research.

Context . Poaching of the African elephant for ivory had been on the increase since 1997 when the Convention on International Trade in Endangered Species (CITES) allowed a one-off legal sale of ivory by several southern Africa countries. In Kenya, reports indicate continuous year-to-year increase in elephant poaching since 2003.

Aims . The goals of the study were to describe the temporal and spatial patterns of elephant poaching in south-eastern Kenya between 1990 and 2009, and examine relationships between observed patterns of poaching, and human and biophysical variables. The study aimed to answer the following questions: (1) how has elephant poaching varied seasonally and annually; (2) what are the spatial patterns of elephant poaching in the Tsavo Conservation Area (TCA); and (3) what are the relationships between observed patterns of poaching and human and biophysical variables?

Methods . The study used elephant-poaching data and various GIS-data layers representing human and environmental variables to describe the spatial and temporal patterns of elephant poaching. The observed patterns were then related to environmental and anthropogenic variables using correlation and regression analyses.

Key results . Elephant poaching was clustered, with a majority of the poaching occurring in the dry season. Hotspots of poaching were identified in areas with higher densities of roads, waterholes, rivers and streams. The Tsavo East National Park and the Tsavo National Park accounted for 53.7% and 44.8% of all poached elephants, respectively. The best predictors for elephant poaching were density of elephants, condition of vegetation, proximity to ranger bases and outposts, and densities of roads and rivers.

Conclusions . Predictor variables used in the study explained 61.5–78% of the total variability observed in elephant poaching. The location of the hotspots suggests that human–wildlife conflicts in the area may be contributing to poaching and that factors that quantify community attitudes towards elephant conservation may provide additional explanation for observed poaching patterns.

Implications . The poaching hotpots identified can be a used as starting point by the Kenya Wildlife Service (KWS) to begin implementing measures that ensure local-community support for conservation, whereas on other hotspots, it will be necessary to beef-up anti-poaching activities. There is a need for Kenya to legislate new anti-poaching laws that are a much more effective deterrence to poaching than currently exist.

Context. Rice-field rodent pests cause substantial economic losses in Asia. In Vietnam, the rice-field rat (Rattus argentiventer) causes 5–10% annual pre-harvest loss in rice yield. A sound ecological knowledge of this species would be useful for developing strategies for managing this pest.

Aims. We tested the hypotheses that there would be changes in the population abundance, breeding performance and habitat use of R. argentiventer in response to rice-crop growth stage.

Methods. Capture–mark–recapture and kill trapping and spool-and-line tracking were used to assess population abundance, breeding and habitat use in different rice-bank habitats, at 3–5-week intervals, through a 2-month flooding period and a rice cropping season. The study was conducted between October 2008 and April 2009 in An Giang Province in The Mekong Delta, Vietnam.

Key results. The population abundance of R. argentiventer was significantly related to rice-crop growth stage and rice-bank habitat. More rats were captured after harvest (P < 0.001) and more were captured in the large and medium-sized banks (P < 0.05). The breeding performance of adult females responded to rice-crop growth stage (P = 0.006). When rice cover was sparse, adult females were located in the burrows during the day, whereas when the cover became abundant, adult females remained in the fields during both the day and at night time. After harvest, rats returned to utilise burrows along rice-field banks.

Conclusions and implications. (1) Rat control activities should be conducted prior to the seedling stage of the rice crop, before the onset of breeding and when vegetative cover is sparse, allowing the animals to be targeted in their burrows; and (2) vegetation on the rice-field banks should be cut to <10 cm to limit the availability of suitable nesting habitat in large and medium-sized banks.

Context . Effective feral-cat (Felis silvestris catus) management requires a sound understanding of the ways cats use their environment. Key characteristics of landscape use by cats vary widely among different regions and different conditions.

Aims . The present study aimed to describe the most important characteristics of landscape use by feral cats on a large, human-populated island, and to use this information to guide the development of feral-cat management programs.

Methods . We used GPS tracking collars to record the movements of 13 feral cats at two sites on Kangaroo Island, South Australia, for between 20 and 106 days. We described home-range extents by using local convex hulls, and derived management suggestions from examination of home-range and movement data.

Key results . Median feral-cat home range was 5.11 km², and this did not differ between sexes or sites. Cats at a fragmented pastoral site tended to favour woody vegetation over open paddocks, but habitat preferences were less clear at a bushland site. Cats that preferentially used treelines at the pastoral site were almost twice as likely to be recorded close to a tree-line junction as expected.

Conclusions . Control programs for feral cats on Kangaroo Island should deploy control devices at a density no less than 1.7 devices km^–2. Spatial coverage should be as large as practicable or repeated frequently. Infrequent programs covering small areas can be expected only to provide short-term reductions in cat abundance.

Implications . The information gained from the present study will contribute to the development of strategic sustained management plans for feral cats on Kangaroo Island. The principles from which we inferred management guidelines are applicable to other regions and species.

Context. Concerns about conservation and ethics in amphibian research have been raised recently; therefore, non-lethal methods should always be preferred to investigate food habits in wild populations. However, there are no studies that compared the data obtained by different non-lethal dietary methods in amphibians.

Aims. We compared the dietary habits obtained from stomach flushing, a method validated against stomach dissection, and faecal analysis on the same 31 individuals of the European plethodontid Speleomantes strinatii, a completely terrestrial salamander.

Methods. After being stomach-flushed in the field, salamanders were kept in the laboratory at constant humidity and temperature to obtain faecal samples. Analyses comprised diversity and niche overlap indexes, as well as permutation, repeated-measures tests and graphical methods.

Key results. Niche overlap between the two samples was low (O_jk = 0.58) and prey diversity was significantly (P = 0.001) higher in stomach contents. There were also differences in the abundance of fly larvae, springtails and ants and the interpretation of the population trophic strategy varied according to the sampling method used.

Key conclusions. Stomach flushing and faecal analysis gave different information, because, apparently, a differential prey degradation occurred. During the digestive process, ants became dominant, whereas springtails and fly larvae became under-represented in faecal samples. Therefore, on the basis of faecal analysis, diet diversity was underestimated and many individuals improperly appeared as ant-specialist feeders.

Implications. In terrestrial salamanders, results from stomach flushing and faecal analysis should not be compared among studies, populations or species. Moreover, stomach flushing should always be preferred when assessing the trophic strategy and the role in food webs of salamanders.

Context. The control of invasive alien species is essential for securing native biodiversity. As for the American bullfrog, Lithobates catesbeianus (Shaw 1802), suspected to cause ecological damage around large parts of the globe, comprehensive management techniques are currently absent.

Aims. To fill this gap, opportunities arising from biomanipulation of permanent water bodies inhabited by fish were explored.

Methods. A multi-annual experiment was performed in small and shallow ponds, and effects of complete drawdown (with amphibian and fish removal) and predation (introduction of originally occurring native northern pike, Esox lucius) on non-indigenous bullfrogs were investigated.

Key results. The presence of pike lead to a strong decline in bullfrog tadpole numbers, whereas no effect of drawdown was observed. Also, communities receiving pike harboured substantially less small and mostly planktivorous fish species (e.g. pumpkinseed, Lepomis gibbosus, and topmouth gudgeon, Pseudorasbora parva).

Conclusions. The reduction in bullfrog tadpoles may be assigned to both direct and indirect effects induced by pike. First, direct pike predation on tadpoles was observed. Second, as the occurrence of macroinvertebrate-feeding pumpkinseed was low in the presence of pike, the indirect effect of predation by macroinvertebrates on tadpoles may significantly increase, leading to tadpole decline.

Implications. Biomanipulation of permanent water bodies inhabited by fish can thus be regarded as a candidate for effective and sustainable control of invasive bullfrog. Piscivorous fish introduction may be applied in the specific type of water body, but requires careful consideration of the indigenous status of the introduced species, angling purposes, or specific nature values.