scholarly journals The importance of fieldwork over predictive modeling in quantifying predation events of carnivores marked with GPS technology

2020 ◽  
Author(s):  
L Mark Elbroch ◽  
B Lowrey ◽  
Heiko Wittmer
Keyword(s):  
Predictive Modeling ◽  
Puma Concolor ◽  
Prey Selection ◽  
Model Performance ◽  
Handling Time ◽  
Gps Collars ◽  
Gps Technology ◽  
Location Data ◽  
Predation Event ◽  
American Society

© 2017 American Society of Mammalogists. Global positioning system (GPS) technology has revolutionized the study of carnivores. Researchers commonly estimate kill rates with GPS data using the following steps. Firstly, researchers mark individual animals and fit them with GPS collars. Next, they visit a subset of "GPS clusters" (aggregated location data) during field surveys and assign spatiotemporal covariates associated with predation and non-predation events. Lastly, they develop predictive models with data collected in the field to estimate the probability that each cluster they did not visit in the field was a predation event. Such predation models help reduce field efforts and save money; however, these models are prone to error when carnivores eat prey of different sizes or exhibit shorter-than-expected handling times. We simulated reduced field efforts to investigate the reliability of predictive modeling in determining diet composition and detecting predation events for 3 puma (Puma concolor) populations with different prey assemblages and potential effects on handling time of carcasses. We visited a total 1,896 clusters in Chilean Patagonia, Colorado, and California, of which 1,752 clusters (∼92%) were included to build and test predation models. Across all study areas, the total time a puma spent at a cluster was the only reliable predictor of a cluster being a predation event. When we reduced field efforts by selectively removing GPS clusters < 12 and < 24 h in length, model performance improved but produced inaccurate results. Predation models underestimated the number of predation events in California and Colorado and significantly over-or underestimated the number of predation events in Patagonia. Selectively reducing field efforts also reduced the diversity and evenness of prey we recorded in puma diets. Randomly reducing field efforts, in contrast, reduced the precision of model estimates. Our results highlight the importance of conducting intensive fieldwork over predation modeling to measure prey selection and kill rates of carnivores.

scholarly journals The importance of fieldwork over predictive modeling in quantifying predation events of carnivores marked with GPS technology

2020 ◽  
Author(s):  
L Mark Elbroch ◽  
B Lowrey ◽  
Heiko Wittmer
Keyword(s):  
Predictive Modeling ◽  
Puma Concolor ◽  
Prey Selection ◽  
Model Performance ◽  
Handling Time ◽  
Gps Collars ◽  
Gps Technology ◽  
Location Data ◽  
Predation Event ◽  
American Society

© 2017 American Society of Mammalogists. Global positioning system (GPS) technology has revolutionized the study of carnivores. Researchers commonly estimate kill rates with GPS data using the following steps. Firstly, researchers mark individual animals and fit them with GPS collars. Next, they visit a subset of "GPS clusters" (aggregated location data) during field surveys and assign spatiotemporal covariates associated with predation and non-predation events. Lastly, they develop predictive models with data collected in the field to estimate the probability that each cluster they did not visit in the field was a predation event. Such predation models help reduce field efforts and save money; however, these models are prone to error when carnivores eat prey of different sizes or exhibit shorter-than-expected handling times. We simulated reduced field efforts to investigate the reliability of predictive modeling in determining diet composition and detecting predation events for 3 puma (Puma concolor) populations with different prey assemblages and potential effects on handling time of carcasses. We visited a total 1,896 clusters in Chilean Patagonia, Colorado, and California, of which 1,752 clusters (∼92%) were included to build and test predation models. Across all study areas, the total time a puma spent at a cluster was the only reliable predictor of a cluster being a predation event. When we reduced field efforts by selectively removing GPS clusters < 12 and < 24 h in length, model performance improved but produced inaccurate results. Predation models underestimated the number of predation events in California and Colorado and significantly over-or underestimated the number of predation events in Patagonia. Selectively reducing field efforts also reduced the diversity and evenness of prey we recorded in puma diets. Randomly reducing field efforts, in contrast, reduced the precision of model estimates. Our results highlight the importance of conducting intensive fieldwork over predation modeling to measure prey selection and kill rates of carnivores.

Seasonal variation in the feeding ecology of pumas (Puma concolor) in northern California

2014 ◽  
Vol 92 (5) ◽  
pp. 397-403 ◽  
Author(s):  
M.L. Allen ◽  
L.M. Elbroch ◽  
D.S. Casady ◽  
H.U. Wittmer
Keyword(s):  
Feeding Ecology ◽  
Ursus Americanus ◽  
Puma Concolor ◽  
Prey Availability ◽  
Black Bear ◽  
Handling Time ◽  
Odocoileus Hemionus ◽  
Odocoileus Hemionus Columbianus ◽  
Gps Collars ◽  
Prey System

Direct effects of predators depend upon factors that can vary across seasons, including variations in the abundance and vulnerability of migrating prey. Past studies show conflicting results of whether puma (Puma concolor (L., 1771)) feeding ecology varies among seasons. We employed GPS collars to study puma feeding ecology in a single-prey system with migratory black-tailed deer (Odocoileus hemionus columbianus (Richardson, 1829)). We hypothesized that puma feeding ecology would vary based on changes in prey abundance and spatial distribution, as well as competition with scavengers and decomposers. Our results supported these hypotheses. Kill rates in number of ungulates/week were significantly higher in summer and autumn than in winter, likely owing to the increased availability and density of black-tailed deer fawns. The handling times of black-tailed deer ≥1 year old were significantly higher in winter than in spring, summer, or autumn. We speculated that reduced handling time in summer may have been influenced by black bear (Ursus americanus Pallas, 1780) kleptoparasitism and the decomposition of kills. Pumas killed black-tailed deer at higher elevations in summer than in winter, spring, or autumn, and the elevations correlated significantly with seasonal elevations used by black-tailed deer, suggesting that pumas exhibited seasonal foraging behaviours and tracked prey availability in a system with migrating prey.

scholarly journals Puma spatial ecology in open habitats with aggregate prey

2020 ◽  
Author(s):  
L Elbroch ◽  
Heiko Wittmer
Keyword(s):  
North America ◽  
Spatial Ecology ◽  
Puma Concolor ◽  
Complex Structure ◽  
Home Ranges ◽  
Foraging Success ◽  
Gps Collars ◽  
Location Data ◽  
Prey Biomass ◽  
Chilean Patagonia

Solitary felids are commonly associated with structurally complex habitats, where their foraging success is attributed to stealth and remaining undetected by competitive scavengers. Research in North America suggests that pumas (Puma concolor), a wide-ranging species found throughout the Americas, conform to the general characteristics of solitary felids and avoid open grasslands with aggregating prey. Researchers hypothesize that pumas are limited to structurally complex habitats in North America because of pressures from other large, terrestrial competitors. We explored the spatial ecology of pumas in open habitat with aggregating prey in Chilean Patagonia, where pumas lack large, terrestrial competitors. We tracked 11 pumas over 30 months (intensive location data for 9 pumas with GPS collars for 9.33±5.66 months each) in an area where mixed steppe grasslands composed 53% of the study area and carried 98% of available prey biomass, to track resource use relative to availability, assess daily movements, quantify home ranges and calculate their density. As determined by location data and kill sites, Patagonia pumas were primarily associated with open habitats with high prey biomass, but at finer scales, preferentially selected for habitat with complex structure. On average, pumas traveled 13.42±2.50km per day. Estimated 95% fixed kernel home ranges averaged 98±31.8km 2 for females and 211±138.8km 2 for males, with high spatial overlap within and between the sexes. In a multivariate analysis, available prey biomass was the strongest predictor of variation in the size of an individual puma's home range. Finally, we determined a total puma density of 3.44pumas/100km 2, a significantly smaller estimate than previously reported for Patagonia, but similar to densities reported for North America. © 2012 Deutsche Gesellschaft für Säugetierkunde.

scholarly journals Puma spatial ecology in open habitats with aggregate prey

2020 ◽  
Author(s):  
L Elbroch ◽  
Heiko Wittmer
Keyword(s):  
North America ◽  
Spatial Ecology ◽  
Puma Concolor ◽  
Complex Structure ◽  
Home Ranges ◽  
Foraging Success ◽  
Gps Collars ◽  
Location Data ◽  
Prey Biomass ◽  
Chilean Patagonia

Solitary felids are commonly associated with structurally complex habitats, where their foraging success is attributed to stealth and remaining undetected by competitive scavengers. Research in North America suggests that pumas (Puma concolor), a wide-ranging species found throughout the Americas, conform to the general characteristics of solitary felids and avoid open grasslands with aggregating prey. Researchers hypothesize that pumas are limited to structurally complex habitats in North America because of pressures from other large, terrestrial competitors. We explored the spatial ecology of pumas in open habitat with aggregating prey in Chilean Patagonia, where pumas lack large, terrestrial competitors. We tracked 11 pumas over 30 months (intensive location data for 9 pumas with GPS collars for 9.33±5.66 months each) in an area where mixed steppe grasslands composed 53% of the study area and carried 98% of available prey biomass, to track resource use relative to availability, assess daily movements, quantify home ranges and calculate their density. As determined by location data and kill sites, Patagonia pumas were primarily associated with open habitats with high prey biomass, but at finer scales, preferentially selected for habitat with complex structure. On average, pumas traveled 13.42±2.50km per day. Estimated 95% fixed kernel home ranges averaged 98±31.8km 2 for females and 211±138.8km 2 for males, with high spatial overlap within and between the sexes. In a multivariate analysis, available prey biomass was the strongest predictor of variation in the size of an individual puma's home range. Finally, we determined a total puma density of 3.44pumas/100km 2, a significantly smaller estimate than previously reported for Patagonia, but similar to densities reported for North America. © 2012 Deutsche Gesellschaft für Säugetierkunde.

scholarly journals Mountain lion ( Puma concolor ) feeding behavior in the Little Missouri Badlands of North Dakota

2015 ◽  
Vol 97 (2) ◽  
pp. 373-385 ◽  
Author(s):  
David T. Wilckens ◽  
Joshua B. Smith ◽  
Stephanie A. Tucker ◽  
Daniel J. Thompson ◽  
Jonathan A. Jenks
Keyword(s):  
North Dakota ◽  
Puma Concolor ◽  
Feeding Habits ◽  
Total Biomass ◽  
Mountain Lions ◽  
Mountain Lion ◽  
Gps Collars ◽  
The North ◽  
Kill Rate ◽  
Prey Populations

Abstract Recent recolonization of mountain lions ( Puma concolor ) into the Little Missouri Badlands of North Dakota has led to questions regarding the potential impacts of predation on prey populations in the region. From 2012 to 2013, we deployed 9 real-time GPS collars to investigate mountain lion feeding habits. We monitored mountain lions for 1,845 telemetry-days, investigated 506 GPS clusters, and identified 292 feeding events. Deer ( Odocoileus spp.) were the most prevalent item in mountain lion diets (76.9%). We used logistic regression to predict feeding events and size of prey consumed at an additional 535 clusters. Our top model for predicting presence of prey items produced a receiver operating characteristic score of 0.90 and an overall accuracy of 81.4%. Application of our models to all GPS clusters resulted in an estimated ungulate kill rate of 1.09 ungulates/week (95% confidence interval [ CI ] = 0.83–1.36) in summer (15 May‒15 November) and 0.90 ungulates/week (95% CI = 0.69–1.12) in winter (16 November‒14 May). Estimates of total biomass consumed were 5.8kg/day (95% CI = 4.7–6.9) in summer and 7.2kg/day (95% CI = 5.3–9.2) in winter. Overall scavenge rates were 3.7% in summer and 11.9% in winter. Prey composition included higher proportions of nonungulates in summer (female = 21.5%; male = 24.8%) than in winter (female = 4.8%; male = 7.5%). Proportion of juvenile ungulates in mountain lion diets increased during the fawning season (June‒August) following the ungulate birth pulse in June (June–August = 60.7%, 95% CI = 43.0–78.3; September–May = 37.2%, 95% CI = 30.8–43.7), resulting in an ungulate kill rate 1.61 times higher (1.41 ungulates/week, 95% CI = 1.12–1.71) than during the remainder of the year (0.88 ungulates/week, 95% CI = 0.62–1.13). Quantifying these feeding characteristics is essential to assessing the potential impacts of mountain lions on prey populations in the North Dakota Badlands, where deer dominate the available prey base and mountain lions represent the lone apex predator.

Hunting Behavior, Prey Selection, and Energetics of Snail Kites in Guyana: Consumer Choice by a Specialist

The Auk ◽  
1983 ◽  
Vol 100 (1) ◽  
pp. 84-92 ◽  
Author(s):  
Steven R. Beissinger
Keyword(s):  
Consumer Choice ◽  
Prey Selection ◽  
Activity Patterns ◽  
Caloric Intake ◽  
Handling Time ◽  
Time Of Day ◽  
Rice Fields ◽  
Hunting Behavior ◽  
Time Activity ◽  
Prey Handling

Abstract The hunting behavior, snail size selection, and time-activity patterns of non-breeding Snail Kites (Rostrhamus sociabilis sociabilis) were studied in Guyana rice fields. Kites spent 62% of the photoperiod perching, 19% foraging, 13% in maintenance activities, and 6% flying. As the day progressed, the percentage of daylight hours spent perching increased significantly, while foraging decreased significantly. Kites successfully captured and ingested Pomacea snails in 78% of the foraging bouts observed. The mode of hunting was evenly split between coursing (50.7%) and still-hunting (49.3%). Searching and returning times were related to time of day, as significantly more coursing hunts and still-hunts occurred in mornings and late afternoons, respectively. Prey handling time was the most time-consuming component of a foraging bout. Time spent searching for prey, returning, or handling prey was not related to snail size. The size distribution of captured snails differed significantly from that of available snails; kites selected more medium snails and fewer small snails and took large snails in equal frequency to that at which large snails were available. Kites captured the same-sized snails when coursing as when still-hunting. As rice grew, kite utilization of rice fields declined, and the frequency of still-hunting decreased while course-hunting attempts increased. The daily caloric intake of kites was estimated to be 104.2 kcal, the daily energy expenditure 85.7 kcal. Results are discussed in relation to consumer choices of specialists. The most important decision a foraging Snail Kite may make is what patch to search in and how long to search before abandoning patches.

scholarly journals Leptodactylus vastus (LEPTODACTYLIDAE) predation on an endemic frog, and a compilation of its diet

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Felipe Eduardo Alves Coelho ◽  
Felipe de Medeiros Magalhães ◽  
Aldenir Ferreira da Silva Neta ◽  
Ricardo Marques
Keyword(s):  
Body Size ◽  
Diet Composition ◽  
Prey Selection ◽  
Striking Difference ◽  
Basic Information ◽  
Widespread Species ◽  
Predation Event ◽  
Mouth Size ◽  
Opportunistic Predator ◽  
History Of

Diet composition constitutes basic information on the natural history of the species. Despite the amount of data acquired in the last years, much remains to be known specially for geographically widespread species. Here we compiled the available dietary items of Leptodactylus vastus and report the first predation event upon Rupirana cardosoi by a juvenile L. vastus. The fact these species are syntopic in the region probably resulted in this novel predation event. Different from previous L. vastus predation observations, the specimens we observed do not present a striking difference in body size, but L. vastus was able to almost swallow L. cardosoi, coherent with findings that mouth size is related to prey selection in anurans. Also, our literature review showed that L. vastus is a generalist and opportunistic predator, that prey upon small vertebrates (Amphibia, Squamata, and Mammalia).

scholarly journals Some ecological aspects of dhole (Cuon alpinus) in the Huai Kha Khaeng Wildlife Sanctuary, Uthai Thani Province, Thailand

2019 ◽  
Vol 46 (2) ◽  
pp. 91-100
Author(s):  
Khwanrutai Charaspet ◽  
Ronglarp Sukmasuang ◽  
Noraset Khiowsree ◽  
Nucharin Songsasen ◽  
Saksit Simchareon ◽  
...  
Keyword(s):  
Prey Selection ◽  
Movement Patterns ◽  
Ecological Knowledge ◽  
Wildlife Sanctuary ◽  
Gps Collars ◽  
Cuon Alpinus ◽  
Ecological Aspects ◽  
Carnivorous Species ◽  
High Degree ◽  
Canid Species

AbstractThe dhole (Cuon alpinus) is one of the least frequent studied endangered canid species and many aspects of ecological knowledge about this species are lacking. The objectives of this study were to investigate the spatial movement of dholes, prey abundance, prey selection, and prey overlaps with other large carnivorous species in the Huai Kha Khaeng Wildlife Sanctuary, Thailand, during November, 2017 and October, 2018. Two adult female dholes were captured and fitted with GPS collars. Twenty camera trap sets were systematically used to survey the area. Scat collection was conducted along forest roads and trails. The home range sizes and activity radii of the two dholes were 3,151.63 ha. and 1,442.84 m, and 33.39 ha and 331.56 m, respectively. The sambar deer (Rusa unicolor) was the most abundant prey species (30.93%). However, dhole fecal analysis showed that the monitored dholes preferred red muntjac (Muntiacus muntjak) (57.1%). There was a high degree of prey overlap between dholes and leopards (98%), indicating very high prey competition. The dholes in this study represent movement patterns in richly abundant prey habitats, but with the presence of other predators that can affect prey selection and movement patterns of the dhole in the area.

scholarly journals Energetics and evasion dynamics of large predators and prey: pumasvs.hounds

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3701 ◽  
Author(s):  
Caleb M. Bryce ◽  
Christopher C. Wilmers ◽  
Terrie M. Williams
Keyword(s):  
Puma Concolor ◽  
Ecosystem Structure ◽  
Canis Lupus Familiaris ◽  
Predator Prey ◽  
Gps Collars ◽  
Physiological Constraints ◽  
Energy Demands ◽  
Group Hunting ◽  
Large Predators ◽  
Free Ranging

Quantification of fine-scale movement, performance, and energetics of hunting by large carnivores is critical for understanding the physiological underpinnings of trophic interactions. This is particularly challenging for wide-ranging terrestrial canid and felid predators, which can each affect ecosystem structure through distinct hunting modes. To compare free-ranging pursuit and escape performance from group-hunting and solitary predators in unprecedented detail, we calibrated and deployed accelerometer-GPS collars during predator-prey chase sequences using packs of hound dogs (Canis lupus familiaris, 26 kg,n = 4–5 per chase) pursuing simultaneously instrumented solitary pumas (Puma concolor, 60 kg,n = 2). We then reconstructed chase paths, speed and turning angle profiles, and energy demands for hounds and pumas to examine performance and physiological constraints associated with cursorial and cryptic hunting modes, respectively. Interaction dynamics revealed how pumas successfully utilized terrain (e.g., fleeing up steep, wooded hillsides) as well as evasive maneuvers (e.g., jumping into trees, running in figure-8 patterns) to increase their escape distance from the overall faster hounds (avg. 2.3× faster). These adaptive strategies were essential to evasion in light of the mean 1.6× higher mass-specific energetic costs of the chase for pumas compared to hounds (mean: 0.76vs.1.29 kJ kg−1 min−1, respectively). On an instantaneous basis, escapes were more costly for pumas, requiring exercise at ≥90% of predicted $\dot {\mathrm{V }}{\mathrm{O}}_{2\mathrm{MAX}}$ and consuming as much energy per minute as approximately 5 min of active hunting. Our results demonstrate the marked investment of energy for evasion by a large, solitary carnivore and the advantage of dynamic maneuvers to postpone being overtaken by group-hunting canids.

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