Trap Success Research Articles

Can non-invasive methods replace radiocollar-based winter counts in a 50-year wolf study? Lessons learned from a three-winter trial

Context Monitoring low-density, elusive predators such as grey wolves (Canis lupus) has often been undertaken via live-capture and radio-collaring. Recent advances in non-invasive methods suggest live-captures may not be necessary for adequate monitoring. Further, non-invasive methods are considered best practice when possible. Aims I evaluated whether a suite of non-invasive methods could replace aerial radiotelemetry to census resident pack wolves. Methods I employed aerial snow-tracking, ground snow-tracking, camera-trapping, non-invasive genetic surveys, and community-scientist reports during three winters (2019–2021) in north-eastern Minnesota, USA to census pack wolves in a 2060 km2 area. I attempted to enumerate individual pack sizes as has been historically undertaken to compile the census. Traditional aerial radiotelemetry methods were also conducted for comparison. Key results Ground snow-tracking and camera-trapping provided the most similar information to radiotelemetry for determining pack counts and territory information, and, in some cases, documented higher pack counts than those obtained by aerial radiotelemetry. Radiotelemetry was the best method for determining pack territories, but was limited to radioed packs. A staggered application of both approaches resulted in increased precision and additional pack-level information without greatly increasing overall field effort. Non-invasive methods allowed trapping for radio-collaring to be reduced to every other year (a 50% reduction), but depending on trapping success, survival of animals, and radio-collar battery life, might even be reduced to every third year. Conclusions In this 3-year trial, non-invasive methods were not sufficient to completely replace radio-collaring. Nevertheless, non-invasive methods allowed for a 50% reduction in trapping, increased the annual wolf-count precision, and increased community involvement. Anticipated technological improvements in non-invasive methods should reduce some issues encountered – but others will likely persist, in part, because of the fundamental nature of non-invasive methods. Implications Less reliance on captures, enhanced pack information, and increased public involvement are all successful outcomes of this 3-year trial of non-invasive methods for monitoring wolf populations. Non-invasive methods continue to broaden and improve technologically, and information from trials such as this will help guide others as they increasingly implement non-invasive methods as partial or complete replacements for traditional capture-based methods.

Site fidelity and other attributes of infrequently trapped bats over two decades in a montane wet sclerophyll forest

A long-term perspective on bat populations is lacking in most ecosystems. We describe fluctuations in capture rate, sex ratio, body condition, site fidelity and longevity of banded bats over two decades as part of an annual banding study in a montane forest. We focus on five species previously omitted from mark–recapture analyses because band returns were too low. Each species was infrequently trapped and/or retrapped, though this was often highly variable. A degree of site fidelity was recorded for all species, even those where trap success was low. We recorded maximum longevity (likely an underestimate) of at least 5 years for eastern falsistrelle Falsistrellus tasmaniensis and 7 years for Gould’s long-eared bat Nyctophilus gouldi and golden-tipped bat Phoniscus papuensis. Although N. gouldi was assumed to be highly detectable in harp traps, recaptures were few and none were retrapped more than once. No female greater-broad-nosed bat Scoteanax rueppellii were captured, a minor male bias was evident for F. tasmaniensis and sex ratios were close to parity for N. gouldi, P. papuensis and eastern horseshoe bat Rhinolophus megaphyllus. Body condition and mass were mostly stable over the study and were not related to periods of drought (except perhaps F. tasmaniensis in 2019) or higher rainfall. Although we recorded some degree of site fidelity among years, the extent of any seasonal or nomadic movements remains largely unknown.

FAKTOR LINGKUNGAN FISIK YANG BERHUBUNGAN DENGAN INDEKS PINJAL KHUSUS DI WILAYAH FOKUS PES (STUDI DI DUSUN SUROROWO, KABUPATEN PASURUAN TAHUN 2018)

Surorowo hamlet in Kalikebek Village, Tutur Subdistrict, Pasuruan Regency, is one of the focus area of plague that has been monitored by the goverment, as an effort to ensure zero deaths of plague. The monitoring results of the specific flea index in 2017 show a fairly high frequency (≥1), which was obtained by calculating the number of Xenopsylla cheopis per number of trap success. This is an indicator that there is still a risk of plague. The purpose of this study is to analyze the physical environmental factors related to the specific flea index in focus area of plague, Surorowo Hamlet. This type of research is analytic observational research with a cross sectional approach. The population in this study were 60 houses that had traps installed by Zoonosis Laboratory field officers to monitor trap success and flea index in the house. The sampling technique used total sampling so that the number of samples was the same as the population, as many as 60 houses. The results showed that there are 4 physical enviromental variables related to the specific flea index, namely the type of house walls (p=0,0), the existance of windows (p=0,0), the existance of ceiling (p=0,0), and the temperature level (p=0,01). Based on the results of this study, to reduce the risk of the high specific flea index in Surorowo Hamlet, the community need to reduce the cavities in the walls that can be a place to live and a path for rats. In addition, it is necessary to procure windows to ensure good lighting and humidity in the house, and reducing wooden dividers on the ceiling of the house so that it does not become a path for rats.

Distribution and Relative Abundance of the Suwannee Alligator Snapping Turtle (Macrochelys suwanniensis)

The Suwannee alligator snapping turtle (Macrochelys suwanniensis) was first described in 2014. The species is thought to occur in blackwater and spring-fed streams of sufficient size throughout the Suwannee River drainage, but we have limited detailed information regarding its range. To clarify the distribution of M. suwanniensis, we compiled 111 museum, 16 literature, and 40 other credible records and trapped streams throughout the Suwannee drainage in Georgia and Florida, plus 8 streams in the Big Bend region of Florida (total of 1893 trap nights). We documented the first records from the Willacoochee River and Okapilco, Piscola, Warrior, Jones, and Toms creeks in Georgia and from Rocky and Olustee creeks in Florida. Relative abundance based on catch per unit effort (CPUE) varied among streams (0.00–0.50) and sections of the same stream. Macrochelys suwanniensis is apparently scarce in the Okefenokee Swamp and in the Suwannee River upstream of White Springs, Florida (none trapped), but it occurs in small blackwater tributaries in this section of the river in both states. In the Suwannee River between White Springs and the estuary, we had a mean CPUE of 0.25, and the highest trapping success in Florida was in downstream reaches of the Suwannee River and in its major tributaries, the Santa Fe and New rivers. The species is widely distributed in Georgia, but relative abundance in most streams appears lower than in Florida. In Georgia, we had the highest trapping success in the Alapaha drainage and in sections of the Little River and Okapilco Creek in the Withlacoochee drainage. In Florida, we failed to trap Macrochelys in the purported distribution gap between the Suwannee and Ochlockonee drainages and in the Wacasassa River to the south, indicating that this species is restricted to the Suwannee drainage.

Peridomestic natural breeding sites of Nyssomyia whitmani (Antunes and Coutinho) in an endemic area of tegumentary leishmaniasis in northeastern Argentina.

The scarce information about breeding sites of phlebotomines limits our understanding of the epidemiology of tegumentary leishmaniasis. Identifying the breeding sites and seasons of immature stages of these vectors is essential to propose prevention and control strategies different from those targeting the adult stage. Here we identified the rural breeding environments of immature stages of Ny. whitmani, vector species of Leishmania braziliensis in the north of Misiones province, Argentina; then we determined and compared the environmental and structural characteristics of those sites. We also identified the season of greatest emergence and its relationship with adult abundance. During a first collection period, between 28 and 48 emergence traps were set continuously for 16 months in six environments of the farm peridomicile and domicile: below house, chicken shed, experimental chicken shed, forest edge, pigsty and under fruit tree. Traps were checked and rotated every 40 nights. A total of 146 newly emerged individuals were collected (93.8% of them were Ny. whitmani), totaling an effort of 23,040 emergence trap-nights. The most productive environments were chicken shed and below house, and the greatest emergence was recorded in spring and summer. During a second collection period, emergence traps and light traps for adult capture were placed in the chicken shed and below house environments of eight farms. Emergence traps were active continuously during spring, summer, and early autumn. Environmental and structural characteristics of each environment were recorded. A total of 84 newly emerged phlebotomines (92.9% Ny. whitmani; 72,144 emergence trap-nights) and 13,993 adult phlebotomines (147 light trap-nights) were recorded in the chicken shed and below house environments. A positive correlation was also observed between trap success of newly emerged phlebotomines and of adults after 120 days. A high spatial variability was observed in the emergence of Ny. whitmani, with the number of newly emerged individuals being highest in soils of chicken sheds with the highest number of chickens and closest to forest edge. Moreover, below house was found to be as important as chicken sheds as breeding sites of Ny. whitmani. Management of the number of chickens in sheds, soil moisture and pH, and the decision of where to localize the chicken sheds in relation to the houses and the forest edge, might contribute to reduce the risk of human vector exposure and transmission of Leishmania.

Camera-Trapping Survey for Plains Spotted Skunk (Spilogale putorius interrupta) in Eastern Oklahoma

Once known as a regularly harvested fur bearer, Spilogale putorius (Eastern Spotted Skunk) has experienced drastic population decline and is now considered a species of conservation concern throughout much of its range. In an effort to contribute to distribution and habitat presence data in Oklahoma, we surveyed 95 locations using camera traps during the months of October and April (2018–2019 and 2019–2020) attempting to detect the S. p. interrupta (Plains Spotted Skunk) subspecies. We began surveying the Ouachita National Forest in eastern Oklahoma and broadened our survey to include areas of recently confirmed sightings. We only detected Eastern Spotted Skunks in 5 of the 95 locations that were surveyed, during 12 of the 5287 trap nights, and 13 of the 2085 mammal detections. Although we had low trap success, we believe our results are useful in supporting the rarity of, or difficulty detecting, this species. Additionally, the information resulting from this study should be useful in establishing a basis for continued sampling in Oklahoma and providing information to improve sampling technique and design when researching this species.

How do you trap a shy wombat? Trialling new trap designs for northern hairy-nosed wombats (

The low trap success (2–4%) of northern hairy-nosed wombats (Lasiorhinus krefftii) has proven a considerable limiting factor to their conservation and management. This project aimed to utilise expert knowledge and experience to redesign current traps and deployment to improve trap success, reduce by-catch and required resources, and improve safety for field staff and captured fauna. A trial of several trap variations and deployment strategies was conducted at Epping Forest National Park (Scientific). Results indicated new trap design and deployment strategies contributed to improving outcomes against all the aims. Most notably, an increased trap success of 10.5% was detected, significantly improving capabilities to achieve conservation and management outcomes.

Keragaman, Dominasi Tikus Silvatik, Kepadatan Pinjal dan Kewaspadaan Pes di Daerah Fokus Pes di Kecamatan Cepogo Kabupaten Boyolali

One of rodent borne diseases that exist in Indonesia is pes with flea as vector and rat as reservoir. The objective of this research were to find out the diversity, dominance of rats, the density of rat and fleas as monitoring efforts for vigilance of plague transmission. The study was conducted in September-October 2016 in Wonodoyo and Kembang Kuning village, Cepogo Sub District of Boyolali District. The research is descriptive with cross sectional approach. Samples collection were conducted by rats survey used single live trap in the silvatic area. The results showed that rats trap success in Wonodoyo village was 3.8% (38 rats) and 1,1% (11 rats) in Kembang Kuning village. Four kind of silvatic rats were Rattus exulans, R. tiomanicus, Niviventer fulvescens and Maxomys surifer. Most of the rats caught (73.68%) in Wonodoyo Village were infested with fleas, while in Kembang Kuning Village it was 27.27%. All of fleas identified as Stivalius cognatus. The specific and general flea index value of S. cognatus in Wonodoyo Village is 2.66; Kembang Kuning Village is 0.45. Early vigilance is very important to do to prevent the transmission of bubonic plague originating from silvatic rats in Cepogo District, particularly in Wonodoyo Village.

Rodent control to fight plague: field assessment of methods based on rat density reduction.

Rodents represent a serious threat to food security and public health. The extent to which rodent control can mitigate the risk from rodent‐borne disease depends on both the effectiveness of control in reducing rodent abundance and the impact on disease epidemiology. Focusing on a plague‐endemic region of Madagascar, this study compared the effectiveness of 3 methods: live‐traps, snap‐traps, and rodenticides. Control interventions were implemented inside houses between May and October 2019. Tracking tiles monitored rodent abundance. Rodent fleas, the vector involved in plague transmission, were collected. Rodent populations consisted of Rattus rattus and Mus musculus. In terms of trap success, we found that our live‐trap regime was more effective than snap‐traps. While all 3 control strategies appeared to reduce in‐house rodent activity in the short term, we found no evidence of a longer‐term effect, with in‐house rodent abundance in treated sites comparable to non‐treatment sites by the following month. Endemic flea, Synopsyllus fonquerniei, is a key plague vector usually found on rats living outdoors. Although we found no evidence that its abundance inside houses increased following control, this may have been due to a lack of power caused by significant variation in S. fonquerniei abundance. The presence of S. fonquerniei in houses was more likely when S. fonquerniei abundance on outdoor rats was higher, which in turn correlated with high rat abundance. Our results emphasize that control strategies need to consider this connectivity between in‐house rat–flea populations and the outdoor populations, and any potential consequences for plague transmission.

Night lighting and anthropogenic noise alter the activity and body condition of pinyon mice (Peromyscus truei)

AbstractAnthropogenic noise and artificial night lighting have been shown to have substantial effects on animal behavior, physiology, and species interactions. Despite the large body of previous work, very few studies have studied the combined effects of light and noise pollution, especially experimentally in the field. Rodents are a highly diverse group that are predominantly nocturnal and occupy a wide range of habitats worldwide, frequently in close association with human development, placing them at a heightened risk from sensory disturbances. To test the singular and combined effects of various levels of anthropogenic light and noise exposure on pinyon mouse (Peromyscus truei) activity and body condition, we used standard trapping methods across a gradient of light and noise and the two combined and accounted for variation of moonlight, vegetation structure, and weather. We hypothesized that increased levels of artificial light would decrease trap success and lead to lower body condition due to an increase in perceived predation risk and that increased noise levels would increase trap success and body condition due to a reduction in predation risk and/or release from competition. Pinyon mouse trap success declined as light intensity increased, and the effect was comparable to that of moonlight, which is well known to influence rodent activity and perception of predation risk. Although noise pollution did not alter trap success of pinyon mice, individuals captured in noisier areas at the beginning of the season had lower body condition than those from quieter areas. Body condition was uninfluenced by noise and light later in the season. We also found no evidence of any additive or synergistic effects of the two stimuli. Our results provide evidence that alterations to the sensory environment from anthropogenic activity can affect wild rodents in several ways. As anthropogenic development increases to meet the demands of growing human populations, more ecosystems will be exposed to increased levels of sensory disturbance, making the understanding of how these changes affect wildlife critical to ongoing conservation efforts.

Range extensions and habitat use of Forrest’s mouse (

Rodent populations are dynamic, and fluctuate with environmental conditions and threatening processes, so their numbers and distributions are not spatially static. Many arid and semi-arid areas also remain poorly surveyed, limiting our understanding of species’ distributions. Fauna surveys in the western division of New South Wales recorded new localities for a previously undetected species – Forrest’s mouse (Leggadina forresti) – in Culgoa and Ledknapper National Parks, equating to an easterly range extension of 430 km. Forrest’s mouse appears to persist in riverine plains, and this habitat may serve as important residual intact habitat within the rangelands of NSW. As a native and vulnerable rodent species that occurs at low density, has low trapping success and occurs in an area that is poorly sampled outside of the reserve system, it should be the target of future survey and conservation efforts within the region.

Spatio-temporal impacts of aerial adulticide applications on populations of West Nile virus vector mosquitoes

BackgroundAerial applications of insecticides that target adult mosquitoes are widely used to reduce transmission of West Nile virus to humans during periods of epidemic risk. However, estimates of the reduction in abundance following these treatments typically focus on single events, rely on pre-defined, untreated control sites and can vary widely due to stochastic variation in population dynamics and trapping success unrelated to the treatment.MethodsTo overcome these limitations, we developed generalized additive models fitted to mosquito surveillance data collected from CO2-baited traps in Sacramento and Yolo counties, California from 2006 to 2017. The models accounted for the expected spatial and temporal trends in the abundance of adult female Culex (Cx.) tarsalis and Cx. pipiens in the absence of aerial spraying. Estimates for the magnitude of deviation from baseline abundance following aerial spray events were obtained from the models.ResultsAt 1-week post-treatment with full spatial coverage of the trapping area by pyrethroid or pyrethrin products, Cx. pipiens abundance was reduced by a mean of 52.4% (95% confidence intrval [CI] − 65.6, − 36.5%) while the use of at least one organophosphate pesticide resulted in a mean reduction of 76.2% (95% CI − 82.8, − 67.9%). For Cx. tarsalis, at 1-week post-treatment with full coverage there was a reduction in abundance of 30.7% (95% CI − 54.5, 2.5%). Pesticide class was not a significant factor contributing to the reduction. In comparison, repetition of spraying over three to four consecutive weeks resulted in similar estimates for Cx. pipiens and estimates of somewhat smaller magnitude for Cx. tarsalis.ConclusionsAerial adulticides are effective for achieving a rapid short-term reduction of the abundance of the primary West Nile virus vectors, Cx. tarsalis and Cx. pipiens. A larger magnitude of reduction was estimated in Cx. pipiens, possibly due to the species’ focal distribution. Effects of aerial sprays on Cx. tarsalis populations are likely modulated by the species’ large dispersal ability, population sizes and vast productive larval habitat present in the study area. Our modeling approach provides a new way to estimate effects of public health pesticides on vector populations using routinely collected observational data and accounting for spatio-temporal trends and contextual factors like weather and habitat. This approach does not require pre-selected control sites and expands upon past studies that have focused on the effects of individual aerial treatment events.Graphical

Records of rat control campaigns in a food market with the largest seafood trading volume worldwide

Brown rats (Rattus norvegicus) and roof rats (Rattus rattus) are among the most common mammals worldwide. Little is known about the effects of season on rat population size, which is important for understanding rat ecology and/or performing effective rat control campaigns. Tsukiji Market was a metropolitan central wholesale market in Tokyo and was located within 1 km from one of the biggest downtown areas. To control rats in the market, a pest management professional exclusively conducted annual campaigns at two fixed time points for many years. In addition, the pest management professional successfully confined all rats to the market and exterminated them when the market was closed and demolished. We analyzed these records to assess whether this rat population in Tokyo showed seasonal fluctuation and to provide information regarding rat management in a facility located in a downtown area. Multiple regression analyses revealed that trap success was affected by human activities (total trading volume and number of foreign tourists in Japan), but not by the month the campaign was performed. These results suggest that the rat population in this market did not show seasonal fluctuation. The results also suggest the importance of the effect of human activities on the ecological dynamics of rats in urban cities. We also described details of the campaigns performed as the market prepared to close to provide information regarding how to control rats in facilities in a downtown area.

Small rodent communities (Muridae) in Gabonese savannas: species diversity and biogeographical affinities

Abstract The study contributes to the knowledge of species composition and biogeographical affinities of savannas rodent in Gabon. Unlike small rodents in Gabonese forests, there is little data on the diversity of small rodents in Gabonese savannas. The diversity and distribution of rodent murid communities was studied in four different types of savanna in Gabon: Coastal Basin (South-West), Lopé/Okanda (in the Center), Batéké Plateaux (Southeastern) and Ngougnié/ N’yanga (in the South). A total of 428 individuals representing six species were captured over 11,920 trap nights. Trap success was highly variable (2.2–6.9 %). The most abundant species were Mus minutoides (69%) followed by Lemniscomys striatus (21.5%). Indices of species richness varied from 2 to 5 and diversity (Shannon and Weaver) was low in the four savannas with the highest value at Ngougnié/N’yanga (H′ = 1.2). Species distributions show that Gabonese savanna small rodents conform to four distribution types, with one species known from Zambesian savannas exhibiting austral affinities (Pelomys campanae: occurs in three southern savannas). This new information provides important insight into the biogeography of small rodents at a local and regional level. Moreover, the correspondence analysis highlighted an influence of local ecological factors on population abundance.

Olfactory lures in predator control do not increase predation risk to birds in areas of conservation concern

Abstract Context Lethal control of predators is often undertaken to protect species of conservation concern. Traps are frequently baited to increase capture efficacy, but baited traps can potentially increase predation risk by attracting predators to protected areas. This is especially important if targeted predators can escape capture due to low trap success. Snake traps using live mouse lures may be beneficial if traps effectively remove snakes in the presence of birds and do not attract additional snakes to the area. Aims The present study evaluated whether mouse-lure traps in areas occupied by birds (simulated by deploying bird-lure traps) could influence predation risk from an invasive snake on Guam. Methods Snake traps were used, with Japanese quail (Coturnix japonica) as a proxy for predation risk, to assess if an adjacent trap with a mouse (Mus musculus) would attract brown treesnakes (Boiga irregularis) to a focal area and increase contact between an invasive snake and avian prey. Catch per unit effort (CPUE) at stations containing either a bird-lure trap, mouse-lure trap or pair of traps (i.e. one bird-lure and one mouse-lure trap) was evaluated. Key results Bird-lure traps paired with mouse-lure traps did not differ in CPUE from isolated bird-lure traps. At paired stations, CPUE of snakes in mouse-lure traps was 2.3× higher than bird-lure traps, suggesting mouse lures were capable of drawing snakes away from avian prey. Bird-lure traps at paired stations experienced a decay in captures over time, whereas CPUE for isolated bird-lure traps increased after 9 weeks and exceeded mouse-lure traps after 7 weeks. Conclusions Mouse lures did not increase the risk of snakes being captured in bird-lure traps. Instead, mouse-lure traps may have locally suppressed snakes, whereas stations without mouse-lure traps still had snakes in the focal area, putting avian prey at greater risk. However, snakes caught with bird lures tended to be larger and in better body condition, suggesting preference for avian prey over mammalian prey in larger snakes. Implications Strategic placement of olfactory traps within areas of conservation concern may be beneficial for protecting birds of conservation concern from an invasive snake predator.

Leptospira spp in Rodents from Peridomestic Sites in Endemic Regions of Nicaragua.

Leptospirosis is one of the most important zoonoses in tropical countries, including Nicaragua, where it is considered endemic. The aim of this study was to determine the frequency of Leptospira spp in rodents captured from peridomestic sites in leptospirosis endemic regions of Nicaragua. Using live traps, 191 rodents were captured in 2012 and 2013 between April and December. Kidney samples were collected and processed for Leptospira detection from 166 animals by direct culture and isolation. The isolates were tested by PCR for LipL32 and lfb1-F genes specific to pathogenic Leptospira species. The trapping success over all sites was 20.2%, with higher rates of success in rainy season (p < 0.05). Leptospira spp were detected in 22.3% of rodents by direct culture methods. Significant differences (p < 0.01) were found in the frequencies of Leptospira positive rodents per month as well as per region. Of the isolated Leptospira spp, 37.5% were positive for pathogenic species by PCR. The frequency of Leptospira positive rodents by isolation could be used as a predictive indicator for the risk of human leptospirosis in Nicaragua.

Trapping White-Tailed Deer (Artiodactyla: Cervidae) in Suburbia for Study of Tick-Host Interaction.

Live capture of white-tailed deer (Odocoileus virginianus) (Zimmermann, 1780) is often necessary for research, population control, disease monitoring, and parasite surveillance. We provide our deer trapping protocol used in a tick-host vector ecology research project and recommendations to improve efficiency of deer trapping programs using drop nets in suburban areas. We captured 125 deer across two trapping seasons. Generally, lower daily minimum temperatures were related to increased capture probability, along with the presence of snow. Our most successful trapping sites were less forested, contained more fragmentation, and greater proportion of human development (buildings, roads, recreational fields). To improve future suburban deer trapping success, trapping efforts should include areas dominated by recreational fields and should not emphasize remote, heavily forested, less fragmented parks. Concurrently, our study illustrated the heterogeneous nature of tick distributions, and we collected most ticks from one trapping site with moderate parameter values between the extremes of the most developed and least developed trapping sites. This emphasized the need to distribute trapping sites to not only increase your capture success but to also trap in areas across varying levels of urbanization and fragmentation to increase the probability of parasite collection.

Species composition, habitat association, altitudinal variation and distribution of small mammals in Chato Protected Area, Western Ethiopia

Species composition, habitat association and altitudinal distribution of rodents and shrews were assessed in Chato Protected Area, Ethiopia, between July, 2015 and March, 2016. The area was stratified into five habitats based on dominant vegetation types and altitudinal zonation. The habitats were Carissa spinarum - Justicia schimperiana, Maytenus gracilipes, Podocarpus falcatus - Pyschotria orophila dominated habitats, riverine and plantation. A total of 254 small mammals comprising five rodent and one shrew species were live trapped from 1862 trap nights. The recorded rodent species were: Stenocephalemys albipes (40.95%), Lophuromys flavopunctatus (23.6%), Arvicanthis sp. (16.9%), Mus mahomet (13%), Mastomys natalensis (4.35%) and a shrew sp. (1.2%). Two of these rodent species (S. albipes and L. flavopunctatus) were the most abundant species that comprised 64.56% of the total; while Crocidura sp. was the least abundant distributed along the centre of the forest. M. gracilipes was dominant at 1,789 to 1,975 m, and was the most diverse habitat and comprised 19.39% of the trap success. P. falcatus- P. orophila was dominant from 1,975 to 2,230 m, and was diverse habitat that comprised 22.7% of the trap success. The plantation supported the least number of rodents. Key words: Altitudinal variation, Chato Protected Area, distribution, habitat, small mammals.

Ideal conditions for increased trapping success of pygmy rabbits (Brachylagus idahoensis) across the Great Basin

Abstract Sagebrush-steppe ecosystems are one of the most imperiled ecosystems in North America and many of the species that rely on these habitats are of great conservation concern. Pygmy rabbits (Brachylagus idahoensis) are one of these species. They rely on sagebrush year-round for food and cover, and are understudied across their range in the intermountain west due in part to their recalcitrance to standard capture techniques. Identifying an efficient and minimally biased trapping method therefore is a critical first step in learning more about this species. We assessed how trap orientation and weather characteristics influenced trap success for Tomahawk traps placed in and around pygmy rabbit burrows by carrying out trapping surveys at 16 occupied pygmy rabbit sites across the Great Basin from 2016 to 2018. We found that pygmy rabbits had a greater probability of being captured in traps with the open end facing away from burrow entrances. Pygmy rabbits also were more likely to be captured on clear days (0–5% cloud cover) and during periods of cooler temperatures during summer months (June–August). We found no evidence that sex or age ratios differed, or that individuals differed meaningfully, in their preference for certain trap orientations. To increase trap success for pygmy rabbits, we suggest maximizing trapping effort during summer months, at dawn, and maximizing the proportion of Tomahawk traps facing away from burrow entrances. We anticipate that our monitoring protocol will enable more effective research into the ecology and conservation of this cryptic and potentially imperiled species.

Population persistence, breeding seasonality and sexual dimorphism in the red-necked wallaby

The red-necked wallaby (Notamacropus rufogriseus) has a broad geographic range along the eastern seaboard of Australia, but ecological research on the mainland subspecies has been limited. We aimed to assess long-term monitoring (1974 to 2017) of abundance at a site in the Grampians National Park in Victoria. Our second aim was to evaluate trap success, sexual dimorphism, breeding seasonality, longevity and home range size from intensive studies (between 2008 and 2017) at this site. The abundance of red-necked wallabies increased over time, showing no negative effect of the arrival of the swamp wallaby (Wallabia bicolor) in the 1970s. Red-necked wallabies were highly trappable: 64% of individuals were retrapped at least once, one was retrapped 38 times, and trap success did not vary seasonally. Red-necked wallabies showed high site-fidelity, with no instances of long-range movements and no sex bias in likelihood of remaining on site. One female was regularly resighted for almost eight years after her initial capture and one male lived to an estimated age of 20 years. All births occurred in the first half of the year, with a marked peak of births in February, and over three-quarters of births occurred in February and March. Red-necked wallabies were highly sexually dimorphic: the largest male (24.5kg) was nearly 10kg heavier than the largest female (15kg), and male home ranges were over five times larger than those of females.