Evaluating Global Positioning System Telemetry Techniques for Estimating Cougar Predation Parameters

Abstract

Using clusters of locations obtained from Global Positioning System (GPS) telemetry collars to identify predation events may allow more efficient estimation of behavioral predation parameters for the study and management of large carnivore predator‐prey systems. Applications of field‐ and model‐based GPS telemetry cluster techniques, however, have met with mixed success. To further evaluate and refine these techniques for cougars (Puma concolor), we used data from visits to 1,735 GPS telemetry clusters, 637 of which were locations where cougars killed prey >8 kg in a multi‐prey system in west‐central Alberta. We tested 1) whether clusters were reliably created at kill locations, 2) the ability of logistic regression models to identify kill occurrence (prey >8 kg) and multinomial regression models to identify the prey species at a kill cluster, and 3) the duration of monitoring required to accurately estimate kill rate and prey composition. We found that GPS collars programmed to attempt location fixes every 3 hours consistently identified locations where prey >8 kg were handled, and cluster creation was robust to GPS location acquisition failures (poor collar fix success). The logistic regression model was capable of estimating cougar kill rate with a mean 5‐fold cross validation error of <10%, provided the appropriate probability cutoff distinguishing kill clusters from non‐kill clusters was selected. Logistic models also can be used to direct visits to clusters, reducing field efforts by as much as 25%, while still locating >95% of all kills. The multinomial model overpredicted occurrence of primary prey (deer) in the diet and underpredicted consumption of alternate prey (e.g., elk and moose) by as much as 100%. We conclude that a purely model‐based approach should be used cautiously and that field visitation is required to obtain reliable information on species, sex, age, or condition of prey. Ultimately, we recommend a combined approach that involves using models to direct field visitation when estimating behavioral predation parameters. Regardless of the monitoring approach, long continuous monitoring periods (i.e., >100 days of a 180‐day period) were necessary to reduce bias and imprecision in kill rate and prey composition estimates.

Effects of Time of Day and Activity Status on Bobcat (Lynx rufus) Cover-Type Selection in Southwestern Georgia

“…Capturing and fitting carnivores with Global Positioning System (GPS) radio-transmitters allows for frequent relocations, which can facilitate location of kill sites (Knopff et al 2009), den locations , day beds (Anderson & Lindzey 2003) and rendezvous sites (Merrill & Mech 2003). Recently, several studies have used GPS technology to better understand prey selection and investigate kill sites of carnivores (Anderson & Lindsey 2003, Cavalcanti & Gese 2010, Ruth et al 2010).…”

“…Recently, several studies have used GPS technology to better understand prey selection and investigate kill sites of carnivores (Anderson & Lindsey 2003, Cavalcanti & Gese 2010, Ruth et al 2010). This technology has been used to document kills by large carnivores including jaguars Panthera onca (Cavalcanti & Gese 2010), cougars Puma concolor (Anderson & Lindsey 2003, Knopff et al 2009) African lions Panthera leo (Tambling et al 2010), leopards Panthera pardus (Martin et al 2011) and gray wolves Canis lupus (Sand et al 2005, Demma et al 2007, Zimmerman et al 2007). However, we are unaware of any study assessing the effectiveness of this technique on medium-sized carnivores.…”

“…a cluster) was a kill site (Knopff et al 2009), fewer have attempted to develop models that researchers can use to increase efficacy of detecting kill sites (e.g. Webb et al 2008, Tambling et al 2010).…”

“…Webb et al 2008, Tambling et al 2010). Metrics used in previous studies include biological factors that may affect predator kill success (habitat type, time of day; Anderson & Lindzey 2003, Webb et al 2008, predator movement characteristics (rate of movement, site fidelity; Knopff et al 2009) and factors that may affect the probability of detecting prey at the kill site (number of locations at cluster, elapsed time from cluster formation to investigation; Sand et al 2005, Zimmerman et al 2007, Knopff et al 2009). Including multiple metrics in model development provides biologists with a comprehensive approach to efficiently identify potential kill sites based on the biological characteristics and movements of the predator while maximizing the probability of detecting a kill site in the field.…”

Scavenging of an Elk, <em>Cervus elaphus</em>, Carcass by Multiple Cougars, <em>Puma concolor</em>, in Southeastern Alberta

“…Even with the advent of Global Positioning Systems (GPS) radiocollars and cluster techniques to locate kill sites (Anderson and Lindzey 2003;Knopff et al 2009), Cougar scavenging events and rates are difficult to quantify. Previous studies (Bauer et al 2005) have shown that Cougars will treat scavenged carcasses similar to their own kills, and will cache and cover them with vegetation and soil.…”