Detection Probability and Sources of Variation in White‐Tailed Deer Spotlight Surveys

Collier, Bret A.; Ditchkoff, Stephen S.; Raglin, Joshua B.; Smith, Jeanette M.

doi:10.2193/2005-728

Cited by 63 publications

(84 citation statements)

References 12 publications

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“…However, the small spotlight sample size and sampling on sequential nights may have tended to underestimate the ' true ' variability in population size. Th is method is mostly used to provide an index of abundance (Focardi et al 2001, Collier et al 2007, Acevedo et al 2008, Garel et al 2010 and we found that absolute abundance estimates from this method were generally not comparable to those from distance sampling. Th is is somewhat expected as the two methods were conducted at diff erent times of the day, and deer generally move out from the forest into the grassland in the evening leading to higher spotlight estimates.…”

Section: Discussionmentioning

confidence: 65%

“I just want to count them! Considerations when choosing a deer population monitoring method”

Amos¹,

Baxter

Finch³

et al. 2014

Wildlife Biology

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Effective management of any population involves decisions based on the levels of abundance at particular points in time. Hence the choice of an appropriate method to estimate abundance is critical. Deer are not native to Australia and are a declared pest in some states where their numbers must be controlled in environmentally sensitive areas. The aim of this research was to help Australian land managers choose between widely used methods to count deer. We compared population estimates or indices from: distance sampling, aerial surveys, spotlight counts, and faecal pellet counts. For each we estimated the labour input, cost, and precision. The coefficient of variation varied with method and time of year from 8.7 to 36.6%. Total labour input per sampling event varied from 11 to 136 h. Total costs of vehicles and equipment per sampling event varied from AU$913 to $2966. Overall, the spotlight method performed the best at our study site when comparing labour input, total cost and precision. However, choice of the most precise, cost effective method will be site specific and rely on information collected from a pilot study, We provide recommendations to help land managers choose between possible methods in various circumstances.

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Section: Discussionmentioning

confidence: 65%

“I just want to count them! Considerations when choosing a deer population monitoring method”

Amos¹,

Baxter

Finch³

et al. 2014

Wildlife Biology

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show abstract

“…For many species, the assumption that all individuals are captured during an abbreviated sampling event is unrealistic, resulting in an underestimate of true populations sizes. Moreover, abundance estimates derived from indices may not always be reliable because of spatial, temporal, or experimental variance in detectability (Anderson 2001, Rosenstock et al 2002, Collier et al 2007). Programs directed at the management of zoonotic diseases are particularly sensitive to the accuracy of population parameters as underestimates of these parameters may limit the success of management programs (Konig et al 2008), whereas overestimates of abundance may inflate costs and increase the likelihood of conflict with non-target species (Flemming et al 2000, Campbell et al 2006.…”

Section: Discussionmentioning

confidence: 99%

A comparison of methods for estimating raccoon abundance: Implications for disease vaccination programs

et al. 2012

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Accurate estimates of demographic parameters are critical to the management of wildlife populations, including management programs focused on controlling the spread of zoonotic diseases. Rabies managers in the United States Department of Agriculture (USDA) have applied a simple raccoon (Procyon lotor) abundance index (RAI) based on cumulative catch of unique raccoons per unit area to determine vaccine‐bait distribution densities. This approach was designed to allow for both the collection of biological samples and to index raccoon abundance to determine bait densities for oral rabies programs. However, post‐baiting surveillance data indicate that, on average, only 30% of raccoons sampled have vaccine induced rabies antibody titers, suggesting that bait densities may not be well calibrated to raccoon densities. We trapped raccoons using both capture‐mark‐recapture (CMR) and the standard RAI to evaluate the accuracy of the current index‐based methodology for estimating raccoon density. We then developed a resource selection function from spatial data collected from radio‐collared raccoons to standardize trap placement within the existing RAI protocol, and evaluated the performance of this modified RAI approach relative to CMR for estimating raccoon population size. Both abundance and density estimates derived using the RAI consistently underestimated raccoon population sizes compared with CMR methods. Similarly, although the use of resource selection models to inform trap placement appeared to improve the accuracy of the RAI, the effectiveness of this method was inconsistent because of an inability to account for variance in detection probabilities. Despite the logistical advantages of using indices to estimate population parameters to determine vaccine bait distribution densities, our results suggest that adjustments may be necessary to more accurately quantify raccoon abundance, which should improve the effectiveness of rabies management in the United States. In particular, estimates of detection probabilities are needed to more precisely quantify abundance estimates and ensure appropriate vaccine coverage rates. © 2012 The Wildlife Society.

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“…Already 40 years ago, thermography was heralded as a promising method for surveying population growth and observing the behavior of large game animals. Collier et al (2007) compared the effectiveness of two methods for detecting white-tailed deer (O. virginianus) populations: thermal imagers (which detected 92.3 % of the deer) and spotlight counts (which detected only 54.4 % of the animals). According to Hodnett (2005), thermal imaging can be successfully applied to detect white-tailed deer in urban areas.…”

Section: Analyses Of Animal Behaviormentioning

confidence: 99%

Infrared thermal imaging in studies of wild animals

et al. 2012

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Thermography is an imaging method which registers infrared waves in the electromagnetic spectrum that are emitted by all objects on the Earth. The state and properties of the studied objects and organisms can be evaluated by analyzing images of temperature distribution on their surface. Thermography has numerous practical applications, including in construction, industry, and the military and civil services. In natural sciences, thermal imaging techniques support safe and non-invasive measurements and the acquisition of results that cannot be obtained by any other method. Infrared thermography also creates a wide range of applications for human and veterinary medicine, ecology, zoology, and other natural sciences. Thermal imaging equipment is used to detect injuries, inflammations, and infectious diseases to control reproduction (detection of estrus and pregnancy, determination of male fertility) and lactation processes. The discussed method is applied to investigate thermoregulation in animals, to analyze the effect of environmental factors on animal behavior, to localize individuals and their habitats, and to determine the size of wildlife populations. Despite a wide range of practical applications, thermal imaging has a number of limitations which should be taken into account in studies that rely on infrared thermography techniques.

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Detection Probability and Sources of Variation in White‐Tailed Deer Spotlight Surveys

Cited by 63 publications

References 12 publications

“I just want to count them! Considerations when choosing a deer population monitoring method”

“I just want to count them! Considerations when choosing a deer population monitoring method”

A comparison of methods for estimating raccoon abundance: Implications for disease vaccination programs

Infrared thermal imaging in studies of wild animals

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