Fishing Cat Ecology: Food Habits, Home Ranges, Habitat Use and Mortality in a Human-Dominated Landscape around Khao Sam Roi Yot, Peninsular Thailand

Abstract

Abstract Despite their global status as an endangered species, many aspects of fishing cat (Prionailurus viverrinus) ecology have not been studied in detail in the wild. The objectives of this study were to understand food habits, habitat use, home range patterns, and causes of mortality in a predominantly agricultural landscape in the area in and around Khao Sam Roi Yot National Park, Prachuap Khiri Khan Province, peninsular Thailand. Few studies have been conducted on the food habits of wild fishing cats and none has been conducted in Southeast Asia. I identified prey remains in fishing cat scats to estimate composition and relative occurrence of major prey groups in the feces of 194 fishing cat scats collected over an approximately 35 km2 area. The proportion of prey remains found in scats was 42% fish, 24% mammals, 24%, birds, 5% reptiles, and 2% crustaceans. There was a significant difference in seasonal prey composition (p = 0.001). During the dry season, 47% of prey remains found was fish, 11 % mammal, 29% bird, 11% reptile, and 3% crustacean. In the wet season, proportions were 36% fish, 39% mammal, 20% bird, 2% reptile, and 1% crustacean. In this study, fishing cat diet varied more than previously reported, both in terms of the diversity of prey and in the proportions of major groups recorded between seasons. To study the home range, habitat use, and mortality of fishing cats, I captured seventeen cats (seven females and 10 males) using box traps and fitted 16 with VHF radio collars. Data from these animals (>1000 locations) were used to estimate home range size and habitat selection. Home range size was estimated using 100% Minimum Convex Polygon (MCP) and the 95% Fixed Kernel (FK) methods. Fishing cats essentially maintained their core area for the duration of the study despite seasonal changes in diet. For the 100% MCP, the area of the male annual home range, F5 was 13.5 km2 and M8 was 4 km2 and the mean for female annual home ranges (n=4) was 4.0 km2. Whereas, the 95% estimates for the male annual home range was 8.8 km2, and the mean annual home range for females was 3.9 km2. Seasonal home range was estimated for one male. His wet season 100% MCP was 10.8 km2, and his 95% fixed kernel was 12.6 km2. In the dry season his 100% MCP home range was 5.7 km2 and the 95% fixed kernel home range was 8.9 km2. For females (n=4), mean wet season 100% MCP home range was 3.2 km2 and the mean 95% fixed kernel was 3.1 km2. The dry season mean 100% MCP was 3.0 km2 and the mean 95% fixed kernel was 3.2 km2. There is evidence of overall home range overlap between females but their 50% area had no overlap. Fishing cats used aquaculture areas and rice fields more frequently, than mangrove restoration areas, and coconut plantations, and human settlement and limestone hills were avoided. One animal used primarily mangrove vegetation (97% of all locations). Coconut plantation was a relatively rare vegetation type within the study area, but it was the most used habitat for one animal in the dry season. Of 16 cats originally collared, five died from confirmed poaching or retribution killing (31.3%), dead from unknown causes (n=6, 37.5%), unknown fate (n=3, 18.8%), and collar malfunction (n=2, 12.5%). Considering that fishing cats have been known to live to 10 years of age, the sample in this study sustained a relatively high mortality rate. Because poaching and retaliatory killing was the main cause of death, the most effective conservation effort for this species in coastal Thailand should focus on decreasing human-fishing cat conflict and poaching.