VU
Large Frogmouth Batrachostomus auritus



Taxonomy

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - A2c+3c+4c

Red List history
Year Category Criteria
2023 Vulnerable A2c+3c+4c
2016 Near Threatened A2c+3c+4c
2012 Near Threatened A2c+3c+4c
2008 Near Threatened A2c; A3c; A4c
2004 Near Threatened
2000 Lower Risk/Near Threatened
1996 Data Deficient
1994 Data Deficient
1988 Near Threatened
Species attributes

Migratory status not a migrant Forest dependency high
Land-mass type continent
shelf island
Average mass -
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 2,410,000 km2 medium
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size unknown - - -
Population trend decreasing poor suspected 2005-2028
Rate of change over the past 10 years/3 generations (longer of the two periods) 26-47,30-45% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 26-47,30-45% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 26-47,30-45% - - -
Generation length 5.41 years - - -
Number of subpopulations 3-50 - - -
Percentage of mature individuals in largest subpopulation 1-89% - - -

Population justification: The global population size has not been quantified but is believed to be large given the range and frequency of records in suitable habitat. It is a highly forest-dependent species that has only occasionally been recorded from undisturbed forest (eBird 2022). Within its range, the rate of forest conversion to plantations, primarily oil palm, has been very rapid over the past few decades (per Global Forest Watch 2022). There are recent records from remaining forested areas across much of the range, however the extent of suitable habitat is now considerably smaller than three generations ago. Where habitat is secure the species continues to be regularly observed, although it is evidently scarce (Eaton et al. 2021, eBird 2022) and observing the species away from protected areas is becoming increasingly difficult.

In Thailand, there is only one definite record, from Nakhon Si Thammarat province (Treesucon and Limparungpatthanakij 2018). There remains a small area of suitable habitat abutting the Malaysian border (with adjacent records). However, if the species does indeed persist in Thailand, its population is likely to be very small, since this is among the best-surveyed and -watched countries within this species' range.

In Peninsular Malaysia, almost all records now come from protected areas in the north or Taman Negara National Park, although there are recent scattered records from elsewhere (MNS Bird Conservation Council 2021, eBird 2022), suggesting the species can be found in most places flat, low-lying habitat remains.
 
On Sumatra, the species has evidently always been scarce but occurred more widely than contemporary records suggest (see van Marle and Voous 1988). In recent years, there are confirmed records from only Way Kambas National Park. Despite ostensibly suitable habitat, and the detection of four other frogmouth species it has, perhaps surprisingly, not been recorded on the Kampar Peninsula (RER 2017, eBird 2022); while presumed to occur there, its population density in forest blocks on the island's east half must be very low. On Sumatra, the population may therefore now be relatively small.

On Borneo, the area of suitable habitat remains large (especially in Kalimantan), although this species still remains one of the most infrequently observed nightbirds across the island away from a handful of sites. Although the population size is not estimated herein, it is unlikely to be small given the extent of suitable habitat. However, determining the species' density in different habitats across its range should be a research priority.

Trend justification: Batrachostomus auritus is thought to be declining rapidly in response to extensive forest cover loss across its range. In the absence of population data, forest cover loss is used as a proxy to estimate the rate of reduction over the past three generations (16.2 years; Bird et al. 2020), however doing this accurately relies on robust knowledge of the species' distribution when forest cover was more extensive. There is, however, much uncertainty on how widespread it was on the Thai-Malay Peninsula and Sumatra historically. Under a range of mapped scenarios, forest cover loss in the species' range is thought to have reduced by 26-47% over the last three generations (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein). Excluding the most extreme of these scenarios (which are considered the least likely), the population is thought to have reduced by 30-45% over the past three generations. This rate is also precautionarily suspected over the next three generations, although beyond that rates of loss may slow as the percentage area of forest outside protected areas diminishes.


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Brunei extant native yes
Indonesia extant native yes
Malaysia extant native yes
Thailand extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Malaysia Danum Valley Conservation Area
Malaysia Endau-Rompin
Malaysia Krau Wildlife Reserve
Malaysia Lambir Hills National Park
Malaysia Mulu - Buda Protected Area
Malaysia Panti forest
Malaysia Similajau National Park
Malaysia Tabin Wildlife Reserve
Malaysia Taman Negara National Park

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland major resident
Forest Subtropical/Tropical Swamp suitable resident
Altitude 0 - 300 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Agro-industry farming Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Annual & perennial non-timber crops - Small-holder farming Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation
Natural system modifications Fire & fire suppression - Increase in fire frequency/intensity Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation

Recommended citation
BirdLife International (2024) Species factsheet: Large Frogmouth Batrachostomus auritus. Downloaded from https://datazone.birdlife.org/species/factsheet/large-frogmouth-batrachostomus-auritus on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/11/2024.