AMUR TIGER PREDATION AND ENERGETIC REQUIREMENTS IN THE RUSSIAN FAR EAST: NEW INSIGHTS FROM GLOBAL POSITIONING SYSTEM COLLARS

The IUCN Red List has classified all subspecies of tigers (Panthera tigris) as endangered with prey depletion being widely recognized as one of the primary drivers of tiger declines. Due to substantial energetic requirements, tigers can only survive and reproduce in areas with healthy prey populations. This may be particularly important for Amur tigers (P. t. altaica) in the Russian Far East, living at the northern limits and with the lowest prey densities of any tiger population. Few studies have been able to rigorously investigate annual prey requirements for any tiger population. We deployed Global Positioning System (GPS) collars on Amur tigers to study annual kill rates and energetic requirements in the Russian Far East. We captured and radio-collared 5 adult tigers from 2009 – 2011 in and around the Sikhote-Alin Biosphere Zapovednik (Reserve) in the Russian Far East. We used GPS locations and 62 known kill sites to build a logistic regression model to predict kills from GPS location clusters. Our top model for predicting kill sites included a temporal component and fidelity to site as covariates (overall classification success 87.11%; ROC = 0.854). Empirical evidence suggests Amur tigers made a kill once every 8.3 days (95% CI 7.2–9.4) and consumed an average of 7.5 kg/day (95% CI 7.4–7.6). We then used empirical movement rates and activity budgets derived from GPS data to estimate the daily energetic requirements for tigers to maintain a subsistence diet. Overall movement rates averaged 888.3 meters/hour, and 6.6 km/day. Our energetics model suggests an average male tiger needs to consume a minimum of 4.9 kg/day, a non-reproductive tigress 3.6 kg/day, and a reproductive tigress raising an average sized litter 7.3 kg/day to maintain a positive energy balance. These are minimum estimates, but clearly illustrate the importance of large ungulate prey because maximum tiger reproduction may require 300% above the average sustenance requirements. This information is critical for conservation and emphasizes that success of current efforts to reverse tiger declines will be defined by managers’ ability to conserve large ungulates to ensure an adequate prey base for recovering tiger populations