Evelyn M Lichwa; Humboldt State University;; James W. Cain III, Genevieve Fuller, Cyrenea Piper, Micaela S. Gunther

Elucidating variables influencing home range size are fundamental ecological relationships that can be described for any species, particularly those of conservation concern. The Mexican wolf (Canis lupus baileyi) is an endangered sub-species of the gray wolf whose home range patterns have not been explicitly studied. We estimated home range sizes for 22 Mexican wolf packs using Brownian Bridge Movement Models (95% UD) and generalized linear mixed effect models to evaluate variables across four timeframes. Home range and pack size fluctuated across timeframes and seasonal ranging patterns mirrored seasonal movements of prey. Annual home range size was inversely correlated with human density, tree cover, and pack size, while during the denning period home range size was inversely correlated by ungulate biomass and litter size and positively correlated with pack size. When packs were traveling at maximum size during the post denning season, home range was inversely correlated with ungulate biomass and positively correlated with pack size. Home range size during the non-denning season was inversely correlated with snow depth. The differing relationships herein demonstrate the importance of analyzing ranging patterns with a multiscale approach for distinct populations to make data driven decisions for management.

Carnivores - Canids and Felids   Student Paper Zoom Presentation



Julia R Lawson; California Department of Fish and Wildlife;; Chris Stermer, California Department of Fish and Wildlife

The Sierra Nevada red fox (Vulpes vulpes necator; SNRF) is a montane subspecies native to California and Oregon. The distribution, abundance, and genetic diversity of the majority of extant SNRF populations have declined substantially since the 1920s, suggesting that a proactive approach will be necessary to recover the subspecies. In 2018, the California Department of Fish and Wildlife convened a team of 35 scientists and resource managers — the SNRF Conservation Advisory Team (SCAT) — to collaboratively develop a range-wide Conservation Strategy for the SNRF. The Strategy is now complete. Building on the latest information about SNRF ecology, distribution, and population status, the Strategy evaluates potential threats to the subspecies, identifies urgent research questions, and presents a framework for implementing management actions to promote recovery. An immediate priority is assessing the feasibility of translocations to achieve a genetic rescue of the SNRF population in the Lassen Peak region, which is extremely vulnerable to extirpation due to small population size, isolation, and inbreeding. The Strategy represents an immense cooperative effort on the part of numerous agencies and individuals across two states. The completion of this document is in itself a conservation success, providing a crucial blueprint for the next steps in SNRF recovery.

Carnivores - Canids and Felids  Zoom Presentation



Holly E. Gamblin; Institute for Wildlife Studies;; Destiny Saucedo, Andrew S. Bridges, David K. Garcelon

The San Clemente Island fox (Urocyon littoralis clementae) is a focal species for conservation by the U.S. Navy and has been monitored on San Clemente Island (SCI) almost continuously since 1988. We used mark-recapture techniques on trapping grids established in 2007 to examine patterns in annual variation of population size, growth, and density by habitat type. Between 2007 – 2020 the SCI fox population grew from an estimated 431 foxes in 2007 to 1,172 in 2020. The ratio of adult females to pups used to index reproduction varied from a low of 0.01 in 2007 to a high of 1.08 in 2017. Overall, the SCI population has steadily grown over the past 20 years. This increase may be related to vegetative recovery following the eradication of feral grazers in 1992 and efforts to reduce the feral cat population which are potential non-native competitors. The low reproductive indices in some years correspond with poor precipitation the preceding winter, and better understanding this relationship has implications for modeling how climate change could impact this population.

Carnivores - Canids and Felids  InPerson Presentation



Matthew P Brinkman; Institute for Wildlife Studies;; David K. Garcelon

Mountain lions (Puma concolor) are relatively well-studied across their range in the United States with a vast amount of information available on home range sizes and variation in diet throughout different habitat types. However, one component of mountain lion life history with a paucity of information is the behavior of female mountain lions during the denning period. We examined spatiotemporal data during the denning period of 7 GPS-collared female mountain lions located in Modoc and Lassen counties in California, beginning with the apparent date of parturition and continuing for 60 days post-partum. Our objectives were to determine whether the amount of time spent away from the den was related to age of the offspring, experience (age) of the mother, relative prey availability, seasonal/temporal factors, or some combination of these variables. We conducted spatial analysis in ArcGIS to measure distances from every location to the den site and determine den attendance rates. We also calculated maximum, minimum, and mean daily distances from the den to use as an index of prey availability. These variables were incorporated into a statistical modeling framework and compared using AIC. Results from this analysis will be included in the presentation.

Carnivores - Canids and Felids  InPerson Presentation



Hunter J Cole; Institute for Wildlife Studies;; David K. Garcelon, Andrew S. Bridges, Grantham R. Lewis, Grantham R Lewis

Native and invasive predators are responsible for billions of dollars in damages annually – a problem often mitigated through lethal removal. Quantifying removal effort effectiveness is critical for sound wildlife management. Here, we demonstrate the use of statistical population reconstruction (SPR) for modeling population trends in lethally-removed mammals. This technique requires minimal resource expenditure beyond routine removal efforts. SPR can be used to reconstruct total population size as well as age demographic structure for lethally-removed mammals for all removal periods for which age-at-harvest data is available. We used SPR to reconstruct a population of feral cats removed from San Clemente Island, California, as part of ongoing endangered passerine recovery efforts. From 2009–2020, 1,952 cats were removed and subsequently aged using cementum annuli analysis. Using age-at-harvest data and a single abundance estimate within an SPR analytical framework, we obtained annual cat population size, age-class structure and harvest probability by age class. The population estimates obtained from this analysis can be used as a parameter in subsequent analyses to monitor removal program efficacy and assess the impact of invasive predator density on native fauna, providing the ability to assess novel removal technique efficacy and prioritize predator removal among other conservation actions.

Carnivores - Canids and Felids  InPerson Presentation