Population Density of the Small Indian Mongoose (Urva auropunctata) Across Multiple Habitat Types and Seasons in Puerto Rico

The small Indian mongoose (Urva auropunctata) is a rabies reservoir on several Caribbean Islands including Puerto Rico. In the continental United States, oral rabies vaccination (ORV) has been used to control and locally eliminate rabies viruses targeting meso-carnivores including raccoons (Procyon lotor), grey foxes (Urocyon cinereoargenteus), and coyotes (Canis latrans), and has more recently been proposed to mitigate and control mongoose rabies in Puerto Rico. A fundamental understanding of the population density of the target species is an important factor in planning bait application rates prior to ORV operations. In Puerto Rico, most ecological studies on mongooses have been restricted to the rainforest region in the northeastern portion of the island. We calculated population density estimates for mongooses at seven sites representing four habitat types in Puerto Rico. We marked 445 unique mongooses across 593 capture events during 12,530 trap days during 2016–2021. Mean (SE, 95% CI) population densities were greater in closed to open broadleaved evergreen forest habitat (0.79 ±0.13, 0.67–0.92 mongooses/ha) compared to grasslands (0.43 ± 0.10; 0.35–0.55 mongooses/ha), rainfed croplands (0.26 ±0.10, 0.18–0.38 mongooses/ha), and shrub/herbaceous habitat (0.19 ±0.05, 0.15–0.25 mongooses/ha). We did not detect seasonal variation in mongoose population density (0.48 [0.06; 0.35–0.62] and 0.39 [0.06; 0.27–0.50] mongooses/ha measured in the wet (May–November) and dry (December–April) seasons, respectively. Multiple ORV applications may be needed annually for adequate population immunity, particularly in habitats with high mongoose population densities and rapid population turnover.