Please come again: attractive bait augments recapture rates of capture-naïve snowshoe hares

2020 ◽  
Vol 47 (3) ◽  
pp. 244
Author(s):  
Melanie R. Boudreau ◽  
Jacob L. Seguin ◽  
Sophia G. Lavergne ◽  
Samuel Sonnega ◽  
Lee Scholl ◽  
...  
Keyword(s):  
Sampling Bias ◽  
Field Trials ◽  
Population Demographics ◽  
Trapping Field ◽  
Snowshoe Hares ◽  
Live Trapping ◽  
Capture Recapture ◽  
Trapping Trials ◽  
Repeat Sampling ◽  
Capture Rates

Abstract ContextCapture–recapture sampling is one of the most commonly used methods for monitoring population demographics and is needed in a wide variety of studies where repeat sampling of individuals is desired. Although studies employing capture–recapture methods often assume unbiased sampling, it is well established that inherent capture biases can occur with these methods, including those related to baits. Reducing sources of sampling bias and augmenting recapture reliability is necessary for capture-dependent studies. However, few studies have examined the efficacy of baits on individuals with variable capture experience. AimsTo investigate the use of an attractant-augmented bait in enhancing capture–recapture probabilities for snowshoe hares (Lepus americanus). MethodsTo examine the efficacy of different attractant-augmented bait types, a variety of baits were created, with bait preference tested on a captive hare. Because a strawberry jam-based bait was preferentially consumed (in comparison with other tested baits), the effectiveness of this attractant in enhancing capture–recapture rates was subsequently examined in wild hares, using paired live-trapping field trials (n=6 trials). ResultsLive-trapping trials showed that although overall hare capture rates were not affected by the use of a jam-based bait, recaptures were 33.1% higher in capture-naïve individuals exposed to our attractant. This was not the case for hares with prior capture experience; such hares had an equal likelihood of being recaptured regardless of the bait type used. ConclusionsThe tested attractant improved recapture rates of capture-naïve hares. ImplicationsStudies relying on high recapture rates should use methods that maximise recapture rates wherever possible, including the use of baits that may augment recaptures in capture-naïve animals.

Evaluating Live trapping and Camera-based Indices of Small Mammal Density

2021 ◽  
Author(s):  
Mitchell Alan Parsons ◽  
ALISHIA ORLOFF ◽  
Laura Prugh
Keyword(s):  
Small Mammal ◽  
Abundant Species ◽  
Monitoring Methods ◽  
Density Estimates ◽  
Full Dataset ◽  
Live Trapping ◽  
Minimum Number ◽  
Capture Recapture ◽  
Two Indices ◽  
Best Fit

Density estimates are integral to wildlife management, but they can be costly to obtain. Indices of density may provide efficient alternatives, but calibration is needed to ensure the indices accurately reflect density. We evaluated several indices of small mammal density using live trapping and motion-activated cameras in Washington’s Cascade Mountains. We used linear regression to compare spatially-explicit capture recapture density estimates of mice, voles, and chipmunks to four indices. Two indices were based on live trapping (minimum number alive and number of captures per 100 trap nights) and two indices were based on photos from motion-activated cameras (proportion of cameras detecting a species and the number of independent detections). We evaluated how the accuracy of trap-based indices increased with trapping effort using subsets of the full dataset (n = 7 capture occasions per site). Most indices provided reliable indicators of small mammal density, and live trapping indices (R2=0.64 – 0.98) outperformed camera-based indices (R2=0.24 – 0.86). All indices performed better for more abundant species. The effort required to estimate each index varied, and indices that required more effort performed better. These findings should help managers, conservation practitioners, and researchers select small mammal monitoring methods that best fit their needs.

Live-capture of feral cats using tracking dogs and darting, with comparisons to leg-hold trapping

2016 ◽  
Vol 43 (4) ◽  
pp. 313 ◽  
Author(s):  
Hugh W. McGregor ◽  
Jordan O. Hampton ◽  
Danielle Lisle ◽  
Sarah Legge
Keyword(s):  
Success Rate ◽  
Success Rates ◽  
Feral Cats ◽  
Factors Affecting ◽  
Setup Costs ◽  
Capture Success ◽  
Physical Injuries ◽  
Live Trapping ◽  
Capture Method ◽  
Capture Rates

Context Predation by feral cats is a key threatening process to many species of native Australian wildlife. Unfortunately, cats are difficult to capture using standard trapping techniques, limiting the potential to conduct research on their ecology and impacts. Aims We present an alternative capture method: remote chemical immobilisation after tracking with trained dogs. We also compare capture rates to a concurrent soft-jaw leg-hold trapping program. Methods We used dogs to capture cats detected by spotlighting at night, and also recaptured cats fitted with telemetry collars during the day. Cats were either bailed on the ground or treed and then hand-netted, or chemically immobilised using darts shot from a CO2-powered dart rifle, loaded with tiletamine–zolazepam at ~6 mg kg–1. Factors affecting the success rate of capturing cats using dogs were assessed. Efficiency in terms of cats captured per person-hours of fieldwork were compared using trained dogs versus leg-hold trapping. Key results We attempted 160 cat captures using the tracking dogs with 114 of those being successful. There were no mortalities or debilitating physical injuries associated with chemical immobilisation; however, sedated cats had prolonged recoveries (>4 h). Capture success with the tracking dogs increased as the dogs gained experience. Capture success rates per person-hour of fieldwork were four times greater using spotlighting with tracking dogs than using leg-hold traps. The success rate of recaptures using dogs was 97%. Conclusions The use of trained tracking dogs proved an effective method for capturing feral cats. The method had a much higher success rate than live-trapping with leg-hold traps, took less effort (in terms of person-hours) and caused less physical injuries than did leg-hold traps. However, substantial setup costs and time are required, which are discussed. Implications Using these methods could improve efficiency and outcomes when catching feral cats, and enable more data per individual cat to be collected than otherwise.

Comparison of capture–recapture estimators of snowshoe hare populations

1994 ◽  
Vol 72 (10) ◽  
pp. 1800-1807 ◽  
Author(s):  
John Boulanger ◽  
Charles J. Krebs
Keyword(s):  
Population Size ◽  
Yukon Territory ◽  
Robust Estimator ◽  
Snowshoe Hare ◽  
Lake Area ◽  
Island Populations ◽  
Snowshoe Hares ◽  
Population Size Estimates ◽  
Size Population ◽  
Capture Recapture

We used two island populations of snowshoe hares (Lepus americanus) in the Kluane Lake area of the Yukon Territory of Canada to evaluate capture – recapture estimators. These islands were intensively sampled, allowing us to enumerate the actual population size. Population size estimates were calculated using the programs CAPTURE and JOLLY, and estimators were compared for bias characteristics. Results from both islands suggest that the CAPTURE heterogeneity models Mh (jackknife), Mh (Chao), and Mth (time – heterogeneity) and the Jolly – Seber model were approximately unbiased. All other CAPTURE models displayed a negative bias. The CAPTURE model selection routine picked estimation models of different biases for each trapping period, an undesirable result. We conclude that it is best to use one robust estimator such as the Mh (jackknife) with snowshoe hare data.

Heterogeneous capture rates in low density populations and consequences for capture-recapture analysis of camera-trap data

2010 ◽  
Vol 53 (1) ◽  
pp. 253-259 ◽  
Author(s):  
Bart J. Harmsen ◽  
Rebecca J. Foster ◽  
C. Patrick Doncaster
Keyword(s):  
Camera Trap ◽  
Low Density ◽  
Capture Recapture ◽  
Capture Rates

Orientation response of Pacific coast wireworm (Coleoptera: Elateridae) to food baits in laboratory and effectiveness of baits in field

2002 ◽  
Vol 134 (3) ◽  
pp. 357-367 ◽  
Author(s):  
David R. Horton ◽  
Peter J. Landolt
Keyword(s):  
Triticum Aestivum ◽  
Oryza Sativa ◽  
Solanum Tuberosum ◽  
Pacific Coast ◽  
Glass Plate ◽  
Field Studies ◽  
Field Trials ◽  
Orientation Response ◽  
Germinating Seeds ◽  
Capture Rates

AbstractAssays were done in the laboratory and field to monitor the response of Pacific coast wireworm, Limonius canus LeConte, to food baits. A glass-plate assay was used in laboratory trials to study movement of wireworm larvae through soil in response to several food baits, including germinating seeds of grains, rolled oats [Avenu sauva L. (Poaceae)], carrot [Daucus carota L. (Umbelliferae)], and potato [Solanum tuberosum L. (Solanaceae)]. Studies were also done with these baits to determine effectiveness under field conditions. In both laboratory and field trials, germinating seed of wheat [Triticum aestivum L. (Poaceae)] and barley [Hordeum vulgare L. (Poaceae)] ranked higher in response by larvae than the remaining food baits. In the glass-plate assays, 65–70% of wireworms contacted the wheat or barley seed baits within a 2-h assay period. Corn [Zea mays L. (Poaceae)] seed and sliced carrot were also effective, with 60% of larvae contacting the baits. Rice [Oryza sativa L. (Poaceae)], rye [Secale cereale L. (Poaceae)], and potato were contacted by 30–45% of larvae. In the majority of assays, contact with the bait occurred within 30 min of the start of the assay. Trail lengths varied substantially among larvae (0–70 cm). The field studies showed that all food baits captured more wireworms than unbaited traps. A second assay conducted in the laboratory showed that moistened rolled oats were contacted with a higher probability if oats were aged 72 h following wetting (51% of larvae contacted the bait) than oats used immediately following wetting (28% of larvae). Field trials using baits composed of different volumes of rolled oats showed little evidence of a dose response in capture rates of L. canus, although all baits captured more wireworms than unbaited traps. These studies showed that L. canus is attracted to food baits in both laboratory and field trials, and that baits may prove useful to monitor populations of this pest in the field.

scholarly journals Non-volant mammal inventory of western Mongolian-Manchurian Grassland Ecoregion: a biogeographic crossroad worth preserving

Check List ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 287-301
Author(s):  
Claudio Augugliaro ◽  
Rasmus Worsøe Havmøller ◽  
Ibra E. Monti ◽  
Linnea Worsøe Havmøller ◽  
Choikhand Janchivlamdan ◽  
...  
Keyword(s):  
Endangered Species ◽  
Threatened Species ◽  
Sand Dune ◽  
Iucn Red List ◽  
Red List ◽  
Biodiversity Hotspot ◽  
Scientific Methods ◽  
Trapping Field ◽  
Live Trapping ◽  
Near Threatened

The extensive Mongolian grasslands hosts a high variety of micro-habitats which wildlife uses as corridors that enable species to expand their range. Between May 2017 and March 2018, we conducted an intensive survey in the Mongolian-Manchurian Grassland Ecoregion using camera trapping, field transects, live trapping and opportunistic observations, in mountain outcrops, grass steppe and sand dune habitats across seasons. Our aim was to compile the first satisfactory inventory of mammals based on scientific methods for a diverse landscape in the Mongolian provinces of Tov and Dundgovi. Furthermore, our research seeks to fill in knowledge gaps on species distribution and range expansions in the endangered west Mongolian-Manchurian Grassland ecoregion and identify biodiversity hotspot areas encompassed in this biogeographic crossroad. We recorded 31 species of non-volant mammals, including a globally Endangered species and two Near Threatened species, according to the IUCN Red List, and three species listed in Appendix II of CITES.

scholarly journals Movement, demographics, and occupancy dynamics of a federally threatened salamander: evaluating the adequacy of critical habitat

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1817 ◽  
Author(s):  
Nathan F. Bendik ◽  
Kira D. McEntire ◽  
Blake N. Sissel
Keyword(s):  
Habitat Use ◽  
Population Connectivity ◽  
Stream Habitat ◽  
Critical Habitat ◽  
Population Demographics ◽  
Occupancy Dynamics ◽  
Habitat Dynamics ◽  
Juvenile Abundance ◽  
Capture Recapture ◽  
Primary Habitat

Critical habitat for many species is often limited to occupied localities. For rare and cryptic species, or those lacking sufficient data, occupied habitats may go unrecognized, potentially hindering species recovery. Proposed critical habitat for the aquatic Jollyville Plateau salamander (Eurycea tonkawae) and two sister species was delineated based on the assumption that surface habitat is restricted to springs and excludes intervening stream reaches. To test this assumption, we performed two studies to understand aspects of individual, population, and metapopulation ecology ofE. tonkawae. First, we examined movement and population demographics using capture-recapture along a spring-influenced stream reach. We then extended our investigation of stream habitat use with a study of occupancy and habitat dynamics in multiple headwater streams. Indications of extensive stream channel use based on capture-recapture results included frequent movements of >15 m, and high juvenile abundance downstream of the spring. Initial occupancy ofE. tonkawaewas associated with shallow depths, maidenhair fern presence and low temperature variation (indicative of groundwater influence), although many occupied sites were far from known springs. Additionally, previously dry sites were three times more likely to be colonized than wet sites. Our results indicate extensive use of stream habitats, including intermittent ones, byE. tonkawae. These areas may be important for maintaining population connectivity or even as primary habitat patches. Restricting critical habitat to occupied sites will result in a mismatch with actual habitat use, particularly when assumptions of habitat use are untested, thus limiting the potential for recovery.

Six reasons why feral house mouse populations might have low recapture rates.

1994 ◽  
Vol 21 (5) ◽  
pp. 559 ◽  
Author(s):  
CJ Krebs ◽  
GR Singleton ◽  
AJ Kenney
Keyword(s):  
Breeding Season ◽  
House Mouse ◽  
Population Increase ◽  
House Mice ◽  
Agricultural Fields ◽  
Breeding Period ◽  
Catch Per Unit Effort ◽  
Live Trapping ◽  
Capture Recapture ◽  
Population Indices

Many feral house mouse populations have low recapture rates (0-20%) in live-trapping studies carried out at 2-4-week intervals. We consider six hypotheses to explain low recapture rates. We radio-collared 155 house mice between September 1992 and May 1993 in agricultural fields on the Darling Downs of south-eastern Queensland during a phase of population increase. Low recapture rates during the breeding season were due to low trappability and during the non-breeding period to nomadic movements. During the breeding season radio-collared mice of both sexes survived well and moved mostly small distances (<ll m). Low trappability has consequences for the precision of population indices that rely on catch per unit effort. Capture-recapture models robust to heterogeneity of trap responses should be used to census feral Mus populations.

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