Prey selection and prey removal by tigertsrnihgeaP (Panthera tigris) during the dry season in lowland Nepal by O.G. ST0EN and P. WEGGE Department of Biology and Nature Conservation, Agricultural University of Norway, P.O. Box 5014, Ν-1432 As, Norway Summary.zyxwvutsrqponmlkihgfedcbaTSRPNLKEDCB - Ecological factors influencing prey selection and prey removal by tigers (Panthera tigris) during the dry season were investigated in the Kamali floodplain in the southwestern part of Royal Bardia National Park, Nepal, between 1990 and 1994. Densities of large herbivore prey were estimated by line transects. Density of tigers was estimated from individual track features. Tiger diet was determined by analyses of scats (feces). Selection of prey species was inferred by comparing observed counts of scats to hypothesized scat frequencies generated from prey density estimates. Prey removal by tigers was estimated from the estimated food requirement of the tigers in the study area and the estimated biomass of the different prey species. Three species (axis deer (Axis axis), wild boar (Sus scrofa) and hog deer (Axis porcinus)) comprised more than 90 % of the biomass killed. Larger and reportedly more optimum sized prey species like nilgai (Boselaphus tragocamelus) and barasingha (Cervus duvauceli) were not preferentially eaten, probably due to their low densities. Contrary to the predictions that tigerzyxwvutsrqponmlkjihgfedcbaTRPNLKIBA prédation would be non-selective on medium and smaller sized prey if availability of large prey was limited, the Kamali tigers showed significant selectivity among the medium sized prey species : wild boar was preferred, whereas barking deerxvutsrponmlkjihgfedcaSRPMCBA (Muntiacus muntjak) was under-represented in the diet. Total removal of available ungulate prey biomass was low (3,1 %) compared to other studies, indicating that the relatively dense tiger population was regulated through social behaviour rather than by food. Prédation by tiger did not appear to play a major role in regula- ting the densities of wild herbivores, except nilgai. In spite of high biomass and diversity of prey, leopard (Panthera pardus) was seemingly displaced to the periphery of the park, suggesting that interspecific prédation rather than food competition excluded coexistence with tigers. Résumé. - Les facteurs écologiques influençant la sélection et le prélèvement des proies par les tigres (Panthera tigris) durant la saison sèche ont été analysés dans la plaine inondable de Kar- nali, partie sud-ouest du Royal Bardia National Park au Népal, entre 1990 et 1994. Les densités de grands herbivores ont été estimées par la méthode des transects en ligne. La densité des tigres a été estimée à partir des caractéristiques des traces, leur régime alimentaire à partir de l'analyse de leurs fèces. La sélection des proies a été inférée à partir de la comparaison entre les nombres observés de restes dans les fèces et des nombres théoriques déduits des densités de proies estimées. Le pré- lèvement de proies par le tigre a été estimé à partir de l'estimation des besoins alimentaires du tigre dans l'aire d'étude, ainsi que de celle de la biomasse des différentes espèces proies. Trois espèces (le cerf Axis (Axis axis), le sanglier (Sus scrofa) et le cerf-cochon (Axis porcinus)) représentaient plus de 90 % de la biomasse tuée. Les proies plus grandes et supposées plus « optimales » pour le tigre comme le nilgaut (Boselaphus tragocamelus) et le barasingha (Cervus duvauceli) n'étaient Mammalia, t. 60, n° 3, 1996 : 363-373. Brought to you by | University of California Authenticated Download Date | 6/2/15 7:46 PM