Nighttime behavioral study of flying foxes on the southern coast of West Java, Indonesia

Abstract

Flying foxes are important in the maintenance of forests and diversity. However, knowledge of their behavioral ecology, especially of movement and foraging patterns, which are essential for conservation and management of their populations, are not well known. Therefore, movement behavior of two individuals of Pteropus vampyrus were examined using an Argos telemetry system, and foraging pattern of Pteropus spp. was directly observed, at West Java province, Indonesia in October 2017. The maximum distance between the location at which bats were released and their furthest roost, recorded via satellite telemetry, was approximately 100 km. This reflects the long-distance flight ability of P. vampyrus. Daytime roosting sites and nighttime foraging places consisted of several types of habitats, such as intact forests, agricultural lands, and residential areas. This evidence indicated that there was habitat overlap between humans and bats in West Java province. According to direct observation of the behaviors of flying foxes at two locations within residential areas, various activities such as wing spreading, excretion, fighting, aggressive calls, movement, hanging relax, and hanging alert were found. The number of bat-visits to the trees varied among night hours, and had a positive correlation with the number of fruit dropping. The data obtained in this study have improved our understanding of nighttime behavior and habitat utilization of P. vampyrus, that can be used to support landscape management, species conservation, and disease prevention in regions of Southeast Asia.

Keywords: Pteropus vampyrus; foraging behavior; satellite telemetry.

Fig. 1.

Map showing the location of capture sites in the Leuweung Sancang conservation area (green area, 7° 43′ 45.12″ S, 107° 54′ 10.08″ E). A: The behavioral study took place in the red star area of the Garut district, Indonesia. There were two study sites for observation. B: At a fig tree in Mekarsari village (7° 38′ 28.9″ S, 107° 46′ 03.8″ E). C: At a mango tree in Sancang village (97° 41′ 44.5″ S, 107° 52′ 59.2″ E).

Fig. 2.

P. vampyrus with solar-powered satellite transmitters.

Fig. 3.

The minimum home range of P. vampyrus (ID 164317) is represented in the yellow polygon. Green dots represent day roost locations, while yellow dots represent night roost locations. The maximum distance from the release point (orange star) to the furthest roost is shown as a dashed line.

Fig. 4.

The minimum home range of P. vampyrus (ID 164319) is represented in the yellow polygon. Green triangles represent day roost locations, while yellow triangles represent night roost locations. The maximum distance from the release point (orange star) to the furthest roost is shown as a dashed line.

Fig. 5.

The number of bat-visits and dropping fruits observed at different times of night at the fig tree study site.

Fig. 6.

The number of bat visits and dropping fruits observed at different times of night at the mango tree study site.