Single-station passive acoustic monitoring of bird diversity and vocal activity in Cikaniki, Gunung Halimun-Salak National Park, West Java

Abstract

Background Montane tropical forests support diverse avian communities, yet dense vegetation and rugged terrain limit conventional surveys.

Objectives This study aimed to assess bird species richness and vocal activity in Cikaniki, Gunung Halimun-Salak National Park, Java, using Passive Acoustic Monitoring (PAM).

Methods Acoustic recordings were collected continuously over 15 days (21 June–6 July 2023) using a fixed PAM station. Vocalizations were identified to species level, categorized as calls or songs, and measured for duration and frequency. Detection frequency across the sampling period was calculated to evaluate temporal patterns of vocal activity.

Results Forty bird species were detected, representing raptors, nocturnal birds, insectivores, frugivores, and nectarivores. Detection frequency varied from a single day to all 15 days. Raptors, such as the Crested Serpent Eagle (Spilornis cheela) and Black Eagle (Ictinaetus malaiensis), were recorded despite high-soaring behavior. Nocturnal species were also captured, showing temporal diversity in vocal activity. Call and song durations ranged from 0.15 to 34.29 s, with frequencies from 617 to 8,577 Hz. Highly vocal species included Blue-eared Barbet (Psilopogon armillaris), Pygmy Wren-Babbler (Pneopyga pusilla), and Orange-bellied Flowerpecker (Dicaeum trigonostigma). 

Conclusions PAM effectively documents both common and elusive species in montane tropical forests. Quantitative acoustic data on detection frequency and vocal behavior provide a baseline for long-term monitoring, supporting adaptive management and conservation of avian communities in Cikaniki and similar habitats.