Distribution and abundance of threatened and heavily traded birds in the mountains of western Java

There is serious concern for the future of a wide range of birds in Java and elsewhere in Indonesia due to both loss of habitat and trapping for the cagebird trade (the so-called Asian Songbird Crisis). Despite this concern, few data on presence and abundance of key species exist. We provide such data on 184 bird species from over two years of biodiversity surveys from 37 sites on 12 mountains in West and Central Java. Many of these species are heavily traded, endemic, and globally threatened. Several of the threatened endemics, notably Javan Trogon and Javan Cochoa, were often recorded, in terms of both geographical spread and numerical abundance. Rufous-fronted Laughingthrush, Spotted Crocias, and Orange-spotted Bulbul, believed to be threatened by trapping for the songbird trade, appear to remain fairly widespread. By contrast, Brown-cheeked Bulbul, Chestnut-backed (Javan) Scimitar-babbler, Javan Oriole, and especially Javan Blue-flycatcher, recorded on just a single occasion, and Javan Green Magpie, which we failed to record with certainty, now appear to be extremely rare. Our encounter rates, while not pinned to specific mountains for security reasons, represent an important baseline against which future changes in abundance can be gauged.

Automated summary

There is serious concern for the future of birds in Java and Indonesia due to habitat loss and trapping for the cagebird trade. We provide data on 184 bird species from biodiversity surveys in West and Central Java, revealing both the presence and abundance of threatened endemics. Some species remain fairly widespread while others, such as the Javan Blue-flycatcher, are now extremely rare. These encounter rates serve as an important baseline for future abundance monitoring.