scholarly journals Automated photogrammetric method to identify individual painted dogs (Lycaon pictus)

2019 ◽  
Vol 29 (2) ◽  
pp. 103-108
Author(s):  
Kanako Ake ◽  
Tadatoshi Ogura ◽  
Yayoi Kaneko ◽  
Gregory S. A. Rasmussen
Keyword(s):  
Camera Trap ◽  
Camera Traps ◽  
Lycaon Pictus ◽  
Accuracy Rate ◽  
Finish Time ◽  
Visual Identification ◽  
Significant Difference ◽  
Trap Height ◽  
Photogrammetric Method ◽  
October 17

The painted dog, Lycaon pictus, has been visually identified by their tricolor patterns in surveys and whilst computerised recognition methods have been used in other species, they have not been used in painted dogs. This study compares results achieved from Hotspotter software against human recognition. Fifteen individual painted dogs in Yokohama Zoo, Japan were photographed using camera-traps and hand-held cameras from October 17–20, 2017. Twenty examinees identified 297 photos visually, and the same images were identified using Hotspotter. In the visual identification, mean accuracy rate was 61.20%, and a mean finish time was 4,840 seconds. At 90.57%, the accuracy rate for Hotspotter was significantly higher, with a mean finish time of 3,168 seconds. This highlights that visual photo-recognition may not be of value for untrained eyes, while software recognition can be useful for this species. For visual identification there was a significant difference in accuracy rates between hand-held cameras and camera-traps whereas for software identification there was no significant difference. This result shows that the accuracy of software identification may be unaffected by the type of photographic device. With software identification there was a significant difference with camera-trap height. This may be because the images of one camera-trap at a lower position became dark due to it being in a shadow.

Camera traps in the canopy: surveying wildlife at tree hollow entrances

2016 ◽  
Vol 22 (1) ◽  
pp. 48 ◽  
Author(s):  
Nigel Cotsell ◽  
Karl Vernes
Keyword(s):  
Anthropogenic Disturbance ◽  
New South ◽  
Camera Trap ◽  
Camera Traps ◽  
North East ◽  
Tree Hollows ◽  
South Wales ◽  
Significant Difference ◽  
Site Disturbance ◽  
Tree Hollow

This is the first comprehensive camera trap study to examine hollow usage by wildlife in the canopy of trees. Eighty cameras directed at tree hollows were deployed across eight sites in nine species of eucalypt in north-east New South Wales. In total, 38 species (including 21 birds, 9 mammals and 8 reptiles) were recorded at hollow entrances over a three-month period. There was a significant difference between wildlife hollow usage associated with site disturbance and tree growth stage (ANOSIM, P > 0.05); however, there was no significant difference associated with tree hollow diameter (ANOSIM, P > 0.05). The level of anthropogenic disturbance at each site, including vegetation modification of the understorey, was a significant predictor of species presence. Despite the limitations of using camera traps in the canopy of trees this study demonstrates the potential to garner useful insights into the ecology and behaviour of arboreal wildlife.

A comparison of vertical and horizontal camera trap orientations for detection of potoroos and bandicoots

2012 ◽  
Vol 34 (2) ◽  
pp. 196 ◽  
Author(s):  
Justine K. Smith ◽  
Graeme Coulson
Keyword(s):  
Species Identification ◽  
Null Model ◽  
Camera Trap ◽  
Probability Of Detection ◽  
Camera Traps ◽  
Camera Lens ◽  
Alternative Method ◽  
Significant Difference ◽  
Detection Probabilities ◽  
Camera Orientation

Camera traps are increasingly used to monitor wildlife that is otherwise difficult to study. Traditionally, camera traps are set aimed horizontally towards a scent lure, capturing images of animals as they move past. A vertical camera orientation is also being used, whereby the camera lens and sensor face vertically down towards the scent lure, capturing images from above. We aimed to compare detection of southern brown bandicoots and long-nosed potoroos by camera traps set horizontally, to those set vertically. We also considered the number of false triggers and ease of species identification. Over 21 nights, we monitored 18 camera stations, each consisting of one PixController Inc. DigitalEye™ 7.2 camera aimed horizontally and one vertically, towards the same scent lure. We used PRESENCE (Version 3.0 (Beta)) to estimate detection probabilities for the two species, comparing a null model to a model with camera orientation as a covariate affecting probability of detection. Detection probabilities for both species was 2–5 times higher by vertical than by horizontal cameras, with no significant difference in false triggers. Vertical cameras also increased ease of species identification. Vertical camera orientation is shown to be superior in our study system, providing a valid alternative method.

High variation in camera trap-model sensitivity for surveying mammal species in northern Australia

2018 ◽  
Vol 45 (7) ◽  
pp. 578 ◽  
Author(s):  
Jaime Heiniger ◽  
Graeme Gillespie
Keyword(s):  
Detection Probability ◽  
High Sensitivity ◽  
Camera Trap ◽  
Camera Traps ◽  
Northern Australia ◽  
Mammal Species ◽  
Survey Tool ◽  
Significant Difference ◽  
Event Trigger ◽  
The Difference

Context The use of camera traps as a wildlife survey tool has rapidly increased, and understanding the strengths and weaknesses of the technology is imperative to assess the degree to which research objectives are met. Aims We evaluated the differences in performance among three Reconyx camera-trap models, namely, a custom-modified high-sensitivity PC850, and unmodified PC850 and HC550. Methods We undertook a controlled field trial to compare the performance of the three models on Groote Eylandt, Northern Territory, by observing the ability of each model to detect the removal of a bait by native mammals. We compared variation in detecting the known event, trigger numbers, proportion of false triggers and the difference in detection probability of small to medium-sized mammals. Key results The high-sensitivity PC850 model detected bait take 75% of the time, as opposed to 33.3% and 20% for the respective unmodified models. The high-sensitivity model also increased the detection probability of the smallest mammal species from 0.09 to 0.34. However, there was no significant difference in detection probability for medium-sized mammals. Conclusions Despite the three Reconyx camera models having similar manufacturer-listed specifications, they varied substantially in their performance. The high-sensitivity model vastly improved the detection of known events and the detection probability of small mammals in northern Australia. Implications Failure to consider variation in camera-trap performance can lead to inaccurate conclusions when multiple camera models are used. Consequently, researchers should carefully consider the parameters and capabilities of camera models in study designs. Camera models and their configurations should be reported in methods, and variation in detection probabilities among different models and configurations should be incorporated into analyses.

Multiple cameras required to reliably detect feral cats in northern Australian tropical savanna: an evaluation of sampling design when using camera traps

2015 ◽  
Vol 42 (8) ◽  
pp. 642 ◽  
Author(s):  
Danielle Stokeld ◽  
Anke S. K. Frank ◽  
Brydie Hill ◽  
Jenni Low Choy ◽  
Terry Mahney ◽  
...  
Keyword(s):  
Camera Trap ◽  
Camera Traps ◽  
Sampling Effort ◽  
Tropical Savanna ◽  
Northern Australia ◽  
Ecological Data ◽  
Detection Rates ◽  
Feral Cats ◽  
Significant Difference ◽  
Trapping Method

Context Feral cats are a major cause of mammal declines and extinctions in Australia. However, cats are elusive and obtaining reliable ecological data is challenging. Although camera traps are increasingly being used to study feral cats, their successful use in northern Australia has been limited. Aims We evaluated the efficacy of camera-trap sampling designs for detecting cats in the tropical savanna of northern Australia. We aimed to develop a camera-trapping method that would yield detection probabilities adequate for precise occupancy estimates. Methods First, we assessed the influence of two micro-habitat placements and three lure types on camera-trap detection rates of feral cats. Second, using multiple camera traps at each site, we examined the relationship between sampling effort and detection probability by using a multi-method occupancy model. Key results We found no significant difference in detection rates of feral cats using a variety of lures and micro-habitat placement. The mean probability of detecting a cat on one camera during one week of sampling was very low (p = 0.15) and had high uncertainty. However, the probability of detecting a cat on at least one of five cameras deployed concurrently on a site was 48% higher (p = 0.22) and had a greater precision. Conclusions The sampling effort required to achieve detection rates adequate to infer occupancy of feral cats by camera trap is considerably higher in northern Australia than has been observed elsewhere in Australia. Adequate detection of feral cats in the tropical savanna of northern Australia will necessitate inclusion of more camera traps and a longer survey duration. Implications Sampling designs using camera traps need to be rigorously trialled and assessed to optimise detection of the target species for different Australian biomes. A standard approach is suggested for detecting feral cats in northern Australian savannas.

Evaluation of the Quality, Educational Value and Utility of the Videos on YouTube for Laparoscopic Low Anterior Resection

2021 ◽  
pp. 000313482110111
Author(s):  
Erol Piskin ◽  
Muhammet Kadri Çolakoğlu ◽  
Ali Bal ◽  
Volkan Oter ◽  
Erdal Birol Bostanci
Keyword(s):  
Anterior Resection ◽  
Low Anterior Resection ◽  
Video Quality ◽  
Relevant Information ◽  
Teaching Quality ◽  
Educational Value ◽  
Laparoscopic Low Anterior Resection ◽  
Significant Difference ◽  
October 17

Background Minimally invasive surgery is a rising trend in colorectal surgery and is on its way to becoming the gold standard due to the benefits it provides for patients. This study aims to test the efficacy for educational purposes by evaluating the videos published on YouTube ( www.youtube.com ) channel for low anterior resection procedure in rectum surgery. Methods We searched YouTube on October 17, 2020 to choose video clips that included relevant information about laparoscopic low anterior resection (LAR) for rectal cancer. Results We included 25 academics and 75 individual videos in this study. The teaching quality of the videos was evaluated according to academic and individual videos, and it was seen that the teaching quality scores of academic videos were higher and this result was statistically significant ( P = .03). The modified Laparoscopic Surgery Video Educational Guidelines (LAP-VEGaS) criteria were found that the score was higher in individual videos ( P = .014). The median Video Power Index (VPI) value was 1.50 (range .05-347) and the mean ratio was 7.01 ± 3.52. There was no statistically significant difference between the 2 groups ( P = .443). Discussion Video-based surgical learning is an effective method for surgical education. Our study showed that the video quality and educational content of most of the videos about the low anterior resection procedure on YouTube were low. The videos of academic origin seem more valuable than individual videos. As far as video popularity is concerned, YouTube viewers are not selective. For this reason, training videos to be used for educational purposes must be passed through a standardized evaluation filter.

scholarly journals Long-term monitoring of margays (Leopardus wiedii): Implications for understanding low detection rates

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247536
Author(s):  
Bart J. Harmsen ◽  
Nicola Saville ◽  
Rebecca J. Foster
Keyword(s):  
Detection Rate ◽  
Camera Trap ◽  
Wide Distribution ◽  
Camera Traps ◽  
Detection Rates ◽  
Terrestrial Mammals ◽  
Exclusive Territories ◽  
Carnivore Species ◽  
Density Population

Population assessments of wide-ranging, cryptic, terrestrial mammals rely on camera trap surveys. While camera trapping is a powerful method of detecting presence, it is difficult distinguishing rarity from low detection rate. The margay (Leopardus wiedii) is an example of a species considered rare based on its low detection rates across its range. Although margays have a wide distribution, detection rates with camera traps are universally low; consequently, the species is listed as Near Threatened. Our 12-year camera trap study of margays in protected broadleaf forest in Belize suggests that while margays have low detection rate, they do not seem to be rare, rather that they are difficult to detect with camera traps. We detected a maximum of 187 individuals, all with few or no recaptures over the years (mean = 2.0 captures/individual ± SD 2.1), with two-thirds of individuals detected only once. The few individuals that were recaptured across years exhibited long tenures up to 9 years and were at least 10 years old at their final detection. We detected multiple individuals of both sexes at the same locations during the same survey, suggesting overlapping ranges with non-exclusive territories, providing further evidence of a high-density population. By studying the sparse annual datasets across multiple years, we found evidence of an abundant margay population in the forest of the Cockscomb Basin, which might have been deemed low density and rare, if studied in the short term. We encourage more long-term camera trap studies to assess population status of semi-arboreal carnivore species that have hitherto been considered rare based on low detection rates.

scholarly journals A sparse observation model to quantify species interactions in time and space

2019 ◽  
Author(s):  
Sadoune Ait Kaci Azzou ◽  
Liam Singer ◽  
Thierry Aebischer ◽  
Madleina Caduff ◽  
Beat Wolf ◽  
...  
Keyword(s):  
Species Interactions ◽  
Activity Patterns ◽  
Niche Partitioning ◽  
Camera Trap ◽  
Camera Traps ◽  
Observation Model ◽  
Occupancy Models ◽  
Time And Space ◽  
Imperfect Detection ◽  
Mobile Species

SummaryCamera traps and acoustic recording devices are essential tools to quantify the distribution, abundance and behavior of mobile species. Varying detection probabilities among device locations must be accounted for when analyzing such data, which is generally done using occupancy models. We introduce a Bayesian Time-dependent Observation Model for Camera Trap data (Tomcat), suited to estimate relative event densities in space and time. Tomcat allows to learn about the environmental requirements and daily activity patterns of species while accounting for imperfect detection. It further implements a sparse model that deals well will a large number of potentially highly correlated environmental variables. By integrating both spatial and temporal information, we extend the notation of overlap coefficient between species to time and space to study niche partitioning. We illustrate the power of Tomcat through an application to camera trap data of eight sympatrically occurring duiker Cephalophinae species in the savanna - rainforest ecotone in the Central African Republic and show that most species pairs show little overlap. Exceptions are those for which one species is very rare, likely as a result of direct competition.

scholarly journals Can citizen science analysis of camera trap data be used to study reproduction? Lessons from Snapshot Serengeti program

2020 ◽  
Author(s):  
Thel Lucie ◽  
Chamaillé-Jammes Simon ◽  
Keurinck Léa ◽  
Catala Maxime ◽  
Packer Craig ◽  
...  
Keyword(s):  
Citizen Science ◽  
Camera Trap ◽  
Camera Traps ◽  
Life History Trait ◽  
List Type ◽  
Breeding Phenology ◽  
Science Data ◽  
Morphological Criteria ◽  
Wide Range ◽  
Trained Observers

AbstractEcologists increasingly rely on camera trap data to estimate a wide range of biological parameters such as occupancy, population abundance or activity patterns. Because of the huge amount of data collected, the assistance of non-scientists is often sought after, but an assessment of the data quality is a prerequisite to their use.We tested whether citizen science data from one of the largest citizen science projects - Snapshot Serengeti - could be used to study breeding phenology, an important life-history trait. In particular, we tested whether the presence of juveniles (less than one or 12 months old) of three ungulate species in the Serengeti: topi Damaliscus jimela, kongoni Alcelaphus buselaphus and Grant’s gazelle Nanger granti could be reliably detected by the “naive” volunteers vs. trained observers. We expected a positive correlation between the proportion of volunteers identifying juveniles and their effective presence within photographs, assessed by the trained observers.We first checked the agreement between the trained observers for age classes and species and found a good agreement between them (Fleiss’ κ > 0.61 for juveniles of less than one and 12 month(s) old), suggesting that morphological criteria can be used successfully to determine age. The relationship between the proportion of volunteers detecting juveniles less than a month old and their actual presence plateaued at 0.45 for Grant’s gazelle and reached 0.70 for topi and 0.56 for kongoni. The same relationships were however much stronger for juveniles younger than 12 months, to the point that their presence was perfectly detected by volunteers for topi and kongoni.Volunteers’ classification allows a rough, moderately accurate, but quick, sorting of photograph sequences with/without juveniles. Obtaining accurate data however appears more difficult. We discuss the limitations of using citizen science camera traps data to study breeding phenology, and the options to improve the detection of juveniles, such as the addition of aging criteria on the online citizen science platforms, or the use of machine learning.

scholarly journals Use of highway culverts by the water opossum (Chironectes minimus) in southeastern Brazil

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Paula Ribeiro Prist ◽  
Guilherme S. T. Garbino ◽  
Fernanda Delborgo Abra ◽  
Thais Pagotto ◽  
Osnir Ormon Giacon
Keyword(s):  
New Records ◽  
Camera Trap ◽  
Sao Paulo ◽  
Riparian Forests ◽  
Camera Traps ◽  
Southeastern Brazil ◽  
São Paulo ◽  
Aquatic Mammal ◽  
Paulo State ◽  
Degraded Area

Abstract The water opossum (Chironectes minimus) is a semi-aquatic mammal that is infrequently sampled in Atlantic rainforest areas in Brazil. Here we report on new records of C. minimus in the state of São Paulo, southeastern Brazil, and comment on its behavior and ecology. We placed nine camera traps in culverts and cattle boxes under a highway, between 2017 and 2019. From a total of 6,750 camera-trap-days, we obtained 16 records of C. minimus (0.24 records/100 camera-trap-days) in two cameras placed in culverts over streams. Most of the records were made between May and August, in the dry season and in the first six hours after sunset. The new records are from a highly degraded area with some riparian forests. The records lie approximately 30 km away from the nearest protected area where the species is known to occur. We suggest that C. minimus has some tolerance to degraded habitats, as long as the water bodies and riparian forests are minimally preserved. The new records presented here also fill a distribution gap in western São Paulo state.

More haste, less speed: pilot study suggests camera trap detection zone could be more important than trigger speed to maximise species detections

2018 ◽  
Vol 40 (1) ◽  
pp. 118 ◽  
Author(s):  
Bronwyn A. Fancourt ◽  
Mark Sweaney ◽  
Don B. Fletcher
Keyword(s):  
Pilot Study ◽  
Wildlife Management ◽  
Detection Probability ◽  
Field Trials ◽  
Camera Trap ◽  
Camera Traps ◽  
Detection Zone ◽  
Trigger Time ◽  
Management Actions ◽  
Context Specific

Camera traps are being used increasingly for wildlife management and research. When choosing camera models, practitioners often consider camera trigger speed to be one of the most important factors to maximise species detections. However, factors such as detection zone will also influence detection probability. As part of a rabbit eradication program, we performed a pilot study to compare rabbit (Oryctolagus cuniculus) detections using the Reconyx PC900 (faster trigger speed, narrower detection zone) and the Ltl Acorn Ltl-5310A (slower trigger speed, wider detection zone). Contrary to our predictions, the slower-trigger-speed cameras detected rabbits more than twice as often as the faster-trigger-speed cameras, suggesting that the wider detection zone more than compensated for the relatively slower trigger time. We recommend context-specific field trials to ensure cameras are appropriate for the required purpose. Missed detections could lead to incorrect inferences and potentially misdirected management actions.

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