Hydrochous gigas


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Hydrochous gigas
Species Authority: (Hartert & Butler, 1901)
Common Name(s):
English Waterfall Swift, Giant Swiftlet
Hydrochrous gigas gigas Collar et al. (1994)
Hydrochrous gigas gigas BirdLife International (2004)

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Benstead, P., Gilroy, J., Taylor, J.
This poorly known species has a disjunct and probably small population, which is thought to be in decline owing to the loss and degradation of forests within its range. It is currently considered Near Threatened, although more detailed surveys are urgently needed to clarify its status.

Geographic Range [top]

Range Description: Hydrochous gigas occurs highly sporadically in the Main Range, Peninsular Malaysia, and the mountains of Sumatra and West Java, Indonesia (Collar et al. 2000). Records from Borneo, in Sarawak and Sabah, Malaysia, and Brunei, involve no specimen evidence and are thus treated provisionally here. All individual populations appear to be small, although one, at Gede-Pangrango, Java, was once fairly large but has seemingly now vanished.

Indonesia; Malaysia
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The global population size has not been quantified, but the species is described as rare and local (del Hoyo et al. 1999).
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: This species occurs over steeply mountainous rainforest, being largely dependent on waterfalls as breeding sites. Altitudinal limits are poorly known, but there are records from 800 m in Peninsular Malaysia, 440 m on Sumatra and 300-1500 m on Java (del Hoyo et al. 1999). Although this species lacks echolocation, it has acute poor-light vision and may be a crepuscular feeder, potentially contributing to the paucity of records.

Systems: Terrestrial; Freshwater

Threats [top]

Major Threat(s): This species may be dependent on areas of forest cover surrounding breeding sites, and therefore be susceptible to the effects of logging and landscape conversion for agriculture. The restricted nature of their waterfall breeding sites may pose an inherent limitation to population size, increasing their susceptibility to disturbance.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
No targeted conservation actions are known for this species.

Conservation Actions Proposed
Conduct surveys throughout the known range in order to determine current status and population size. In particular, clarify its presence, abundance and distribution on Borneo. Conduct ecological studies to explore habitat requirements, particularly the link to rainforest cover surrounding breeding sites. Protect areas of suitable habitat from clearance, degradation and disturbance.

Citation: BirdLife International 2012. Hydrochous gigas. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 04 September 2015.
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