Factors affecting the success rate of traps for catching feral pigs in a tropical habitat

1994 ◽  
Vol 21 (3) ◽  
pp. 287 ◽  
Author(s):  
P Caley
Keyword(s):  
Success Rate ◽  
Vegetation Type ◽  
Northern Territory ◽  
Trap Site ◽  
Wet Season ◽  
Factors Affecting ◽  
Feral Pigs ◽  
Time Of Year ◽  
Open Woodland ◽  
Capture Rates

Factors affecting the success rate of traps for catching feral pigs inhabiting a tropical habitat in the Northern Territory, Australia, were identified by constructing a generalised linear model relating capture rates of pigs to environmental variables. Capture rates were influenced most significantly by time of year, being highest during the late dry season and lowest during the late wet season. The next-most important variables were the presence of fresh pig-tracks at the trap site before construction, and vegetation type, with capture rates higher in closed forest, open forest and woodland habitats than in open woodland and low open woodland habitats. Other variables that significantly influenced capture rates were whether pigs had previously eaten bait at the trap site, presence of rooting, bait type, and distance from water. The model developed here provides a useful framework of planning and conducting feral pig trapping programmes in the Northern Territory and other similar tropical habitats.

Problem crocodiles, Crocodylus porosus, at Nhulunbuy, Northern Territory: an assessment of relocation as a mangaement strategy

1993 ◽  
Vol 20 (1) ◽  
pp. 127 ◽  
Author(s):  
B Walsh ◽  
PJ Whitehead
Keyword(s):  
Carrying Capacity ◽  
Northern Territory ◽  
Effective Strategy ◽  
Wet Season ◽  
Rates Of Return ◽  
Saltwater Crocodile ◽  
Crocodylus Porosus ◽  
Remote Sites ◽  
Total Capture ◽  
Capture Rates

Since 1986 the Conservation Commission of the Northern Territory has operated a programme to remove 'problem' saltwater crocodiles from waters in and adjoining the township of Nhulunbuy. Over a period of five years, 52 different saltwater crocodiles (44 male) were captured. Most (48) were released at remote sites designated by the traditional Aboriginal owners of the surrounding lands. Release distances from the township varied from 17 to 282 km (by coastline). Many crocodiles (47.9%), including those released at the most distant sites, returned to, and were subsequently recaptured at, the township. Total capture rates (initial captures and recaptures pooled) varied seasonally, with fewer crocodiles being caught in the cooler dry season. During the wet season capture rates remained high, but relatively fewer 'new' crocodiles were caught. Probability of recapture could not be related to distance and direction of release from the township, nor size and sex of the released crocodile. Frequency of capture of individual crocodiles (1-8 times) was also unrelated to these variables. The high rates of return indicate that relocation is unlikely to be an effective strategy for managing humancrocodile interactions, at least in areas where potential release sites already support saltwater crocodile populations near carrying capacity.

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.

Factors Affecting Bait Uptake and Trapping Success for Feral Pigs (Sus Scrofa) in Kosciusko National Park.

1993 ◽  
Vol 20 (5) ◽  
pp. 653 ◽  
Author(s):  
G Saunders ◽  
B Kay ◽  
H Nicol
Keyword(s):  
National Park ◽  
New South ◽  
Radio Telemetry ◽  
Cumulative Number ◽  
Factors Affecting ◽  
Feral Pigs ◽  
South Wales ◽  
Population Reduction ◽  
Time Of Year ◽  
Bait Stations

An evaluation of the rate and extent of population reduction that can be achieved by trapping feral pigs was conducted in a subalpine area of Kosciusko National Park in south-eastern New South Wales. Movements of pigs during the programme were monitored by radio-telemetry. In total, 142 pigs, including 12-17 (71%) previously fitted with transmitters and known to be still on the study site, were captured over 330 trap-nights at a cost of $A104 per pig. A model fitted to the change in percentage of bait stations eaten per day relative to the cumulative number of pigs caught estimated a population reduction of 62% of animals exposed to traps and only 28% of the entire population. Determinants of trap success are discussed. During the trapping evaluation and in 2 preceding seasons, factors that influenced the rate at which bait stations were found and eaten were also examined. Both the locality characteristics of bait stations and the time of year were found to have significant effects on this rate.

Accuracies of Computer versus Manual Linkages of Routine Health Records

1979 ◽  
Vol 18 (02) ◽  
pp. 89-97 ◽  
Author(s):  
Martha E. Smith ◽  
H. B. Newcombe
Keyword(s):  
Success Rate ◽  
Record Linkage ◽  
Central Processor ◽  
Processor Time ◽  
Health Records ◽  
Factors Affecting ◽  
Linkage Methods ◽  
Empirical Tests ◽  
Speed Accuracy ◽  
Computer Operation

Empirical tests of the application of computer record linkage methods versus the use of routine clerical searching, for bringing together various vital and ill-health records, have shown that the success rate for the computer operation was higher (98.3 versus 96.7 per cent) and the proportion of false linkages very much lower (0.1 versus 2.3 per cent). The rate at which the ill-health records were processed by the computer was approximately 14,000 per minute of central processor time, representing a cost of a half a cent apiece.Factors affecting the speed, accuracy and cost of computerized record linkage are discussed.

Application of Automated FIB for TEM Sample Preparation in Semiconductor Failure Analysis

2014 ◽  
Author(s):  
Jie Zhu ◽  
Soo Sien Seah ◽  
Irene Tee ◽  
Bing Hai Liu ◽  
Eddie Er ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Success Rate ◽  
Protective Layer ◽  
Factors Affecting ◽  
Dual Beam ◽  
Lamella Thickness ◽  
Surface Patterns ◽  
Working Parameters ◽  
Practical Factors ◽  
High Flexibility

Abstract In this paper, we describe automated FIB for TEM sample preparation using iFast software on a Helios 450HP dual-beam system. A robust iFast automation recipe needs to consider as many variables as possible in order to ensure consistent sample quality and high success rate. Variations mainly come from samples of different materials, structures, surface patterns, surface topography and surface charging. The recipe also needs to be user-friendly and provide high flexibility by allowing users to choose preferable working parameters for specific types of samples, such as: grounding, protective layer coating, milling steps, and final TEM lamella thickness/width. In addition to the iFast recipe, other practical factors affecting automation success rate are also discussed and highlighted.

scholarly journals Using areas of known occupancy to identify sources of variation in detection probability of raptors: taking time lowers replication effort for surveys

2016 ◽  
Vol 3 (10) ◽  
pp. 160368 ◽  
Author(s):  
Campbell Murn ◽  
Graham J. Holloway
Keyword(s):  
Detection Probability ◽  
Spatial Scales ◽  
Survey Methods ◽  
A Priori ◽  
Low Density ◽  
Occupancy Models ◽  
Imperfect Detection ◽  
Factors Affecting ◽  
Sources Of Variation ◽  
Time Of Year

Species occurring at low density can be difficult to detect and if not properly accounted for, imperfect detection will lead to inaccurate estimates of occupancy. Understanding sources of variation in detection probability and how they can be managed is a key part of monitoring. We used sightings data of a low-density and elusive raptor (white-headed vulture Trigonoceps occipitalis ) in areas of known occupancy (breeding territories) in a likelihood-based modelling approach to calculate detection probability and the factors affecting it. Because occupancy was known a priori to be 100%, we fixed the model occupancy parameter to 1.0 and focused on identifying sources of variation in detection probability. Using detection histories from 359 territory visits, we assessed nine covariates in 29 candidate models. The model with the highest support indicated that observer speed during a survey, combined with temporal covariates such as time of year and length of time within a territory, had the highest influence on the detection probability. Averaged detection probability was 0.207 (s.e. 0.033) and based on this the mean number of visits required to determine within 95% confidence that white-headed vultures are absent from a breeding area is 13 (95% CI: 9–20). Topographical and habitat covariates contributed little to the best models and had little effect on detection probability. We highlight that low detection probabilities of some species means that emphasizing habitat covariates could lead to spurious results in occupancy models that do not also incorporate temporal components. While variation in detection probability is complex and influenced by effects at both temporal and spatial scales, temporal covariates can and should be controlled as part of robust survey methods. Our results emphasize the importance of accounting for detection probability in occupancy studies, particularly during presence/absence studies for species such as raptors that are widespread and occur at low densities.

Thinking honeyeater: nectar maps for the Northern Territory, Australia

2000 ◽  
Vol 6 (1) ◽  
pp. 61 ◽  
Author(s):  
John C. Z. Woinarski ◽  
Greg Connors ◽  
Don C. Franklin
Keyword(s):  
Northern Territory ◽  
Dry Season ◽  
Spatial And Temporal Variation ◽  
Wet Season ◽  
Nectar Production ◽  
The World ◽  
Eucalypt Forests ◽  
The Times ◽  
Species Specific ◽  
Nectar Availability

We create monthly maps of nectar availability for the 1.4 x 106 km2 jurisdiction of the Northern Territory, Australia. These are based on a combination of vegetation mapping and a series of indices of plant species specific nectar scoring. The maps reveal complex spatial and temporal variation in nectar availability, but most notably a greater nectar resource in the monsoon-influenced north than in the arid south, and a peak in nectar availability in the dry season. The latter is associated with the extensive tropical eucalypt forests (especially those co-dominated by Eucalyptus miniata and E. tetrodonta). In contrast, wet season nectar availability in these forests is limited, but riparian and swampland forests, typically dominated by Melaleuca species, provide rich but spatially restricted nectar resources. The extensive and rich nectar resources available in eucalypt forests in the dry season supplement the diets of many species which are not primarily nectarivorous. This resource helps shape the singularity of northern Australian eucalypt forests relative to other extensive forests elsewhere in the world. Nectarivores remain in the system through a combination of movements across a number of scales, habitat shifting, and diet shifting. The latter is aided by the peaking of invertebrate and fruit resources at the times of minimum nectar production; a shuffling in resource availability brought about by the extreme climatic seasonality.

The Spatial and Temporal Distribution of Lightning Strikes and Their Relationship with Vegetation Type, Elevation, and Fire Scars in the Northern Territory

2007 ◽  
Vol 20 (7) ◽  
pp. 1161-1173 ◽  
Author(s):  
Musa Kilinc ◽  
Jason Beringer
Keyword(s):  
Large Scale ◽  
Vegetation Type ◽  
Northern Region ◽  
Northern Territory ◽  
Southern Region ◽  
Transitional Period ◽  
Geographical Information ◽  
Coastal Regions ◽  
Fire Scars ◽  
Lightning Strikes

Abstract In this paper the authors explore the spatial and temporal patterns of lightning strikes in northern Australia for the first time. In particular, the possible relationships between lightning strikes and elevation, vegetation type, and fire scars (burned areas) are examined. Lightning data provided by the Bureau of Meteorology were analyzed for a 6-yr period (1998–2003) over the northern, southern, and coastal regions of the Northern Territory (NT) through the use of Geographical Information Systems (GIS) to determine the spatial and temporal characteristics of lightning strikes. It was determined that the highest densities of lightning strikes occurred during the monsoon transitional period (dry to wet) and during the active monsoon periods, when atmospheric moisture is highest. For the period of this study, lightning was far more prevalent over the northern region (1.21 strikes per km2 yr−1) than over the southern (0.58 strikes per km2 yr−1) and coastal regions (0.71 strikes per km2 yr−1). Differences in vegetation cover were suggested to influence the lightning distribution over the northern region of the NT, but no relationship was found in the southern region. Lightning strikes in the southern region showed a positive relationship with elevations above 800 m, but no relationship was found in the northern region, which could be due to the low-lying topography of the area. A comparison of lightning densities between burned and unburned areas showed high variability; however, the authors suggest that, under ideal atmospheric conditions, large-scale fire scars (>500 m) could produce lightning strikes triggered by either enhanced free convection or mesoscale circulations.

scholarly journals Surgical outcomes of acute acquired comitant esotropia of adulthood

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dae Hyun Kim ◽  
Ha Jeong Noh
Keyword(s):  
Success Rate ◽  
Surgical Outcomes ◽  
Medical Records ◽  
Large Angle ◽  
Sudden Onset ◽  
Prism Diopter ◽  
Factors Affecting ◽  
The Mean ◽  
Motor Outcomes

Abstract Background Acute acquired comitant esotropia (AACE) is a type of strabismus characterized by a sudden onset of large angle esotropia with diplopia, which often occurs in children after infancy, teenagers, and young adolescents. However, studies on the surgical outcomes of only adults are rare. The purpose of this article is to analyze the surgical outcomes for adult patients diagnosed with AACE. Methods Medical records of 24 patients who had undergone surgery for AACE were retrospectively analyzed. The main outcome measures were the final motor and sensory success rate after surgery and factors affecting motor and sensory outcomes. Motor success was considered alignment within 8 prism diopter (PD) at both near and distance and sensory success was stereoacuity ≥ 60 sec/arc. Results The preoperative mean esodeviation angles were 33.1 ± 10.4 PD at distance and 33.3 ± 11.2 PD at near. The mean period of postoperative follow up was 7.5 ± 4.5 months (range 1–8 months). The postoperative mean esodeviation angles at final follow-up time were 3.4 ± 6.1 PD at distance and 3.8 ± 6.7 PD at near. The surgical motor success rate at final follow-up was 79.2% (19/24). The sensory success rate at final follow-up was 50.0% (12/24). The factor affecting the motor outcome was the type of surgery (p < 0.05). The factor affecting sensory outcome was postoperative follow-up time (p < 0.05). Conclusions Surgery type appears to affect surgical motor outcomes in adults with AACE. Although the sensory outcome was favorable, it seems that regaining bifoveal fixation takes time.

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