NT
Forest Thrush Turdus lherminieri



Taxonomy

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2019 Near Threatened A2c+4c
2018 Vulnerable A2cde
2016 Vulnerable A2cde
2012 Vulnerable A2cde+4cde
2008 Vulnerable A2c,d,e
2004 Vulnerable
2000 Vulnerable
1994 Lower Risk/Near Threatened
1988 Lower Risk/Least Concern
Species attributes

Migratory status not a migrant Forest dependency High
Land mass type Average mass 105 g
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 14,800 medium
Number of locations 11-100 -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 100000-499999 poor estimated 2018
Population trend Unknown poor suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) 20-29 - - -
Number of subpopulations 5 - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 4.4 - - -

Population justification: Point counts on Montserrat found c.1,200 individuals at 88 stations in the Centre Hills in 2016 (Bambini et al. 2017). As these stations covered only 20-40% of the available forest habitat (Oppel et al. 2014), the population on Montserrat could be between 1,500 - 10,000 individuals (1,000-7,000 mature individuals). A recent study based on surveys and habitat mapping on Guadeloupe has suggested that previous population estimates have been substantial underestimates, with the Guadeloupe population estimated at 46,900 – 49,500 pairs (93,800 – 99,000 mature individuals; Eraud et al. 2012). However, the estimate was based on distance sampling which can be highly inaccurate in dense tropical forests given that most Forest Thrush detections are aural. The sizes of the populations on Dominica and St Lucia are unknown, although the latter is assumed to be very small, if not zero. The total population is therefore placed in the band 100,000-499,999 mature individuals.

Trend justification: The species underwent a significant population reduction over recent decades, particularly during 1995-1997, when the range on Montserrat was reduced by two-thirds by the effects of volcanic eruptions and ash fall (G. Hilton in litt. 2000). However, more recent data has suggested that the species’s population may no longer be declining. In December 1999, the population on Montserrat was estimated at 3,100 birds (Arendt et al. 1999), representing an increase of c.50% since December 1997, with further increases up until 2004, followed by a period of stability and further increased between 2011 and 2016 (Parashuram 2013, S. Oppel in litt. 2016, Bambini et al. 2017, S. Oppel in litt. 2019). Montserrat thus holds a small proportion of the global population, which is stable or slowly increasing. On St Lucia, there has been just one recent record (at Des Chassin in 2007), but it was considered numerous in the late 19th century, indicating a serious long-term decline, if not extirpation (Keith 1997, B. Ibene in litt. 2014, L. John in litt. 2016, S. Oppel in litt. 2019). Little is known about population trend on Dominica, but the population size is likely low. As a consequence of hurricane Maria, which hit the island in 2017, the population may likely have declined further, though it is still observed there (see recent records on eBird; eBird 2018). The majority of the population is found on Guadeloupe (Eraud et al. 2012), and all evidence suggests only a very slow decline. Precautionarily, it is assumed that the historic decline on St Lucia, the potentially large declines on Dominica and the very slow declines on Guadeloupe sum up to such a magnitude that the species’s global population is currently in decline at a rate approaching 30% over three generations.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Dominica N Extant Yes
Guadeloupe (to France) N Extant Yes
Montserrat (to UK) N Extant Yes
St Lucia N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Montserrat (to UK) Centre Hills
Montserrat (to UK) Northern Forested Ghauts
Montserrat (to UK) South Soufriere Hills
St Lucia Castries and Dennery Waterworks Reserve and Marquis
Guadeloupe (to France) Forestry massif of Basse-Terre island
Guadeloupe (to France) Grand Cul-de-Sac Marin's eastern coastline
Dominica Morne Trois Pitons National Park
Dominica Morne Diablotin National Park

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Montane major resident
Altitude 0 - 1400 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species mortality
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Ecosystem degradation, Ecosystem conversion
Geological events Volcanoes Timing Scope Severity Impact
Past, Likely to Return Minority (<50%) Rapid Declines Past Impact
Stresses
Ecosystem degradation, Ecosystem conversion
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Herpestes javanicus Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Molothrus bonariensis Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Unspecified species Timing Scope Severity Impact
Ongoing Minority (<50%) No decline Low Impact: 4
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Turdus nudigenis Timing Scope Severity Impact
Ongoing Minority (<50%) No decline Low Impact: 4
Stresses
Competition

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Food - human - - Non-trivial Recent

Recommended citation
BirdLife International (2021) Species factsheet: Turdus lherminieri. Downloaded from http://www.birdlife.org on 01/12/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 01/12/2021.