scholarly journals A Comparison of Four Survey Methods for Detecting Fox Squirrels in the Southeastern United States

2016 ◽  
Vol 7 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Daniel U. Greene ◽  
Robert A. McCleery ◽  
Lindsay M. Wagner ◽  
Elina P. Garrison

Abstract Fox squirrel Sciurus niger populations in the southeastern United States appear to have declined, and 3 (S. n. cinereus, S. n. shermani, and S. n. avicennia) of the 10 subspecies are currently listed with a conservation status of protection. Efforts to conserve and manage fox squirrels in the southeastern United States are constrained by difficulties in studying their populations because of low densities and low detectability. There is a need for an effective survey method to fill knowledge gaps on southeastern fox squirrel ecology. To address this need and to identify a cost-effective and reliable technique to survey and monitor southeastern fox squirrel populations, we compared four survey methods across seasons: live-trapping; camera-trapping; point counts; and line-transect surveys, in regard to whether a detection occurred at a survey point, the total number of detections at a survey point, and the total cost for each method. We assessed the effectiveness of capture and detection methods and the influence of seasonality using generalized linear mixed models. We found camera-trapping to be the most effective survey method for assessing the presence and distribution of southeastern fox squirrels. In total, camera-traps produced significantly more detections (n = 223) of fox squirrels than all other methods combined (n = 84), with most detections occurring in spring (n = 97) and the fewest in the autumn (n = 60). Furthermore, we detected fox squirrels at more survey points with camera-traps (73%) than all other methods (63%), and we identified 16% more individuals from camera-trap photographs than live-trapped. We recommend future monitoring of southeastern fox squirrels to be conducted using camera-trapping during the spring unless handling of animals is needed for other research purposes.

2019 ◽  
Vol 46 (2) ◽  
pp. 104 ◽  
Author(s):  
Shannon J. Dundas ◽  
Katinka X. Ruthrof ◽  
Giles E. St.J. Hardy ◽  
Patricia A. Fleming

Context Camera trapping is a widely used monitoring tool for a broad range of species across most habitat types. Camera trapping has some major advantages over other trapping methods, such as pitfall traps, because cameras can be left in the field for extended periods of time. However, there is still a need to compare traditional trapping methods with newer techniques. Aims To compare trap rates, species richness and community composition of small mammals and reptiles by using passive, unbaited camera traps and pitfall traps. Methods We directly compared pitfall trapping (20-L buried buckets) with downward-facing infrared-camera traps (Reconyx) to survey small reptiles and mammals at 16 sites within a forested habitat in south-western Australia. We compared species captured using each method, as well as the costs associated with each. Key results Overall, we recorded 228 reptiles, 16 mammals and 1 frog across 640 pitfall trap-nights (38.3 animal captures per 100 trap-nights) compared to 271 reptiles and 265 mammals (for species likely to be captured in pitfall traps) across 2572 camera trap nights (20.8 animal captures per 100 trap-nights). When trap effort is taken into account, camera trapping was only 23% as efficient as pitfall trapping for small reptiles (mostly Scincidae), but was five times more efficient for surveying small mammals (Dasyuridae). Comparing only those species that were likely to be captured in pitfall traps, 13 species were recorded by camera trapping compared with 20 species recorded from pitfall trapping; however, we found significant (P<0.001) differences in community composition between the methods. In terms of cost efficacy, camera trapping was the more expensive method for our short, 4-month survey when taking the cost of cameras into consideration. Conclusions Applicability of camera trapping is dependent on the specific aims of the intended research. Camera trapping is beneficial where community responses to ecosystem disturbance are being tested. Live capture of small reptiles via pitfall trapping allows for positive species identification, morphological assessment, and collection of reference photos to help identify species from camera photos. Implications As stand-alone techniques, both survey methods under-represent the available species present in a region. The use of more than one survey method improves the scope of fauna community assessments.


2020 ◽  
Vol 40 (3) ◽  
pp. 392-403 ◽  
Author(s):  
Paul D. Meek ◽  
Guy Ballard ◽  
Greg Falzon ◽  
Jaimen Williamson ◽  
Heath Milne ◽  
...  

Camera trapping has advanced significantly in Australia over the last two decades. These devices have become more versatile and the associated computer technology has also progressed dramatically since 2011. In the USA, the hunting industry drives most changes to camera traps; however the scientific fraternity has been instrumental in incorporating computational engineering, statistics and technology into camera trap use for wildlife research. New survey methods, analytical tools (including software for image processing and storage) and complex algorithms to analyse images have been developed. For example, pattern and texture analysis and species and individual facial recognition are now possible. In the next few decades, as technology evolves and ecological and computational sciences intertwine, new tools and devices will emerge into the market. Here we outline several projects that are underway to incorporate camera traps and associated technologies into existing and new tools for wildlife management. These also have significant implications for broader wildlife management and research.


2015 ◽  
Vol 39 (3) ◽  
pp. 645-650 ◽  
Author(s):  
Courtney A. Tye ◽  
Daniel U. Greene ◽  
William M. Giuliano ◽  
Robert A. Mccleery

2016 ◽  
Vol 38 (1) ◽  
pp. 44 ◽  
Author(s):  
Paul D. Meek ◽  
Karl Vernes

Camera trapping is increasingly recognised as a survey tool akin to conventional small mammal survey methods such as Elliott trapping. While there are many cost and resource advantages of using camera traps, their adoption should not compromise scientific rigour. Rodents are a common element of most small mammal surveys. In 2010 we deployed camera traps to measure whether the endangered Hastings River mouse (Pseudomys oralis) could be detected and identified with an acceptable level of precision by camera traps when similar-looking sympatric small mammals were present. A comparison of three camera trap models revealed that camera traps can detect a wide range of small mammals, although white flash colour photography was necessary to capture characteristic features of morphology. However, the accurate identification of some small mammals, including P. oralis, was problematic; we conclude therefore that camera traps alone are not appropriate for P. oralis surveys, even though they might at times successfully detect them. We discuss the need for refinement of the methodology, further testing of camera trap technology, and the development of computer-assisted techniques to overcome problems associated with accurate species identification.


2017 ◽  
Vol 44 (8) ◽  
pp. 637 ◽  
Author(s):  
Emily Richardson ◽  
Dale G. Nimmo ◽  
Sarah Avitabile ◽  
Lauren Tworkowski ◽  
Simon J. Watson ◽  
...  

Context Passive infrared cameras have become a widely utilised method for surveying mammals, providing substantial benefits over conventional trapping methods. Cameras have only recently been tested for their ability to survey terrestrial reptiles, and have not yet been tested against other reptile survey methods for their comparative effectiveness. Aims To investigate the reliability of passive infrared cameras as a reptile survey method, compared with pitfall trapping. In addition, to test a refinement of a current protocol for using cameras to survey reptiles. Methods The study was carried out in the herpetologically diverse, semiarid Mallee region of Victoria, Australia. Paired camera and pitfall lines were set up at 10 sites within Murray Sunset National Park and results from the two methods were compared. A comparison of results from cameras with and without the use of a cork tile substrate was also made. Key results Cameras were just as effective as pitfall traps for detecting some common diurnal species – detecting additional species that pitfalls did not – but were significantly less effective overall. Cameras provided lower estimates of species richness and failed to detect nocturnal species. We also discovered that cork tiles, required in other environments for the cameras to be effective in detecting diurnal reptiles, were not needed here. Conclusions Cameras can be an effective, efficient non-invasive alternative to conventional trapping methods, such as pitfall trapping, for surveying some terrestrial diurnal reptile species. However, further investigation into using cameras for surveying nocturnal reptile species is still required. Implications If the methodological issues identified during this study can be overcome, passive infrared cameras have the potential to be a valuable tool for future herpetological research.


Mammalia ◽  
2017 ◽  
Vol 81 (2) ◽  
Author(s):  
Matthew J. Brady ◽  
John L. Koprowski ◽  
R. Nathan Gwinn ◽  
Yeong-Seok Jo ◽  
Kevin Young

AbstractThe eastern fox squirrel, native to the eastern and midwestern United States, was recently documented in the Sonoran Desert in the vicinity of Yuma, Arizona, constituting the first state record for this species. We surveyed the people of Yuma to determine when and how the squirrels arrived. The squirrels were first observed in the 1960s, but may have been resident for a longer period. Since the 1960s, squirrels have spread throughout the city limits and extended south ~15 km into Somerton, Arizona. How the squirrels arrived is not clear, but must be the result of an introduction, as no nearby populations exist. The persistence of eastern fox squirrels in this unique habitat is due to synanthropic relationships.


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