Bicknell's Thrush Catharus bicknelli


Taxonomic note

Taxonomic source(s)
AOU. 1998. Check-list of North American birds. American Ornithologists' Union, Washington, D.C.
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.
Stotz, D. F.; Fitzpatrick, J. W.; Parker, T. A.; Moskovits, D. K. 1996. Neotropical birds: ecology and conservation. University of Chicago Press, Chicago.

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

Red List history
Year Category Criteria
2016 Vulnerable A2c+3c+4c
2012 Vulnerable A2c+3c+4c
2008 Vulnerable A2c; A3c; A4c; B1a+b(i,ii,iii,iv,v)
2004 Vulnerable
2000 Vulnerable
1994 Not Recognised
1988 Not Recognised
Species attributes

Migratory status full migrant Forest dependency High
Land mass type Land-mass type - continent
Average mass -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 790,000 medium
Extent of Occurrence non-breeding (km2) 509,000 medium
Number of locations 11-100 -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 63300-84000 medium estimated 2010
Population trend Decreasing 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) 30-49 - - -
Decline (10 years/3 generation past and future) 30-49 - - -
Number of subpopulations 1 - - -
Largest subpopulations 100 - - -
Generation length (yrs) 4.2 - - -

Population justification: The current population estimate for the species in Canada is between 40,570 and 49,258 individuals (COSEWIC 2009), with global estimates of 95,000-126,000 individuals (IBTCG 2010), probably including c.63,300-84,000 mature individuals.

Trend justification: Breeding population trend data for the species are sparse, but generally indicate declines, especially in core and northern parts of the range. Annual declines of 7-19% have been documented in parts of the species’s breeding range (IBTCG 2010). A rapid population decline is suspected overall, based on these data, and owing to the on-going loss and conversion of the species's wintering habitat. In the past, acid rain may have reduced available habitat. Potential future threats include global warming.

Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Canada N Extant Yes
Cuba N Extant Yes
Dominican Republic N Extant Yes
Haiti N Extant Yes
Jamaica N Extant Yes
Martinique (to France) N Extant
Puerto Rico (to USA) N Extant Yes
USA N Extant Yes
Virgin Islands (to USA) V Extant

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Canada Cape Breton Highlands National Park
Canada Cape North
Canada Central Cape Breton Highlands
Canada Massif du mont Gosford
Canada Mont Mégantic
Canada Mount Carleton Provincial Park
Canada Nepisiguit Highlands
Cuba Turquino - Bayamesa
Dominican Republic Armando Bermudez National Park
Dominican Republic Del Este National Park
Dominican Republic Haitises
Dominican Republic Honduras
Dominican Republic Loma Guaconejo
Dominican Republic Loma La Humeadora
Dominican Republic Loma Quita Espuela
Dominican Republic Nalga de Maco-Río Limpio
Dominican Republic Sierra de Bahoruco
Dominican Republic Sierra Martin Garcia
Dominican Republic Valle Nuevo
Haiti Aux Becs-Croisés
Haiti Aux Cornichons
Haiti Aux Diablotins
Jamaica Blue Mountains
USA Adirondack High Peaks Forest Tract
USA Catskills Peaks Area
USA High Elevation Spruce-Fir
USA Northern Adirondack Peaks
USA Northern Green Mountains IBA

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Rural Gardens suitable non-breeding
Forest Subtropical/Tropical Moist Lowland suitable non-breeding
Forest Subtropical/Tropical Moist Montane major non-breeding
Forest Temperate major breeding
Altitude 350 - 2200 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Future Whole (>90%) Unknown Unknown
Ecosystem degradation
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Future Unknown Unknown Unknown
Species disturbance
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases Timing Scope Severity Impact
Ongoing Unknown Unknown Unknown
Species mortality
Pollution Air-borne pollutants Timing Scope Severity Impact
Past, Likely to Return Whole (>90%) Slow, Significant Declines Past Impact
Ecosystem degradation
Residential & commercial development Tourism & recreation areas Timing Scope Severity Impact
Past, Likely to Return Minority (<50%) No decline Past Impact
Ecosystem degradation, Ecosystem conversion

Recommended citation
BirdLife International (2018) Species factsheet: Catharus bicknelli. Downloaded from on 17/07/2018. Recommended citation for factsheets for more than one species: BirdLife International (2018) IUCN Red List for birds. Downloaded from on 17/07/2018.