NT
Spotted Owl Strix occidentalis



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
- - -

Red List history
Year Category Criteria
2017 Near Threatened A2abce+3bce+4abce; C2a(i)
2016 Near Threatened C2a(i)
2013 Near Threatened C2a(i)
2012 Near Threatened C2a(i)
2008 Near Threatened C2a(i)
2004 Near Threatened
2000 Lower Risk/Near Threatened
1994 Lower Risk/Near Threatened
1988 Threatened
Species attributes

Migratory status altitudinal 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) 3,920,000 medium
Number of locations -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 15000 medium estimated 2003
Population trend Decreasing good 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) 20-29 - - -
Decline (10 years/3 generation past and future) 20-29 - - -
Number of subpopulations - - -
Largest subpopulations - - -
Generation length (yrs) 10.1 - - -

Population justification: Its population size is estimated at c.15,000 mature individuals (Rich et al. 2004).

Trend justification: Trend analyses using Christmas Bird Count (CBC) data gathered since 1965-1966 suggest that this species’s population is not declining, and may even be increasing slightly (Butcher and Niven 2007); however, CBC data are not regarded as sufficiently reliable for monitoring population trends in this species because it is rarely encountered during the CBC and because it is a highly desired species by observers, perhaps resulting in special efforts to find it - efforts that may have become more successful over time with the accumulation of knowledge (G. Butcher in litt. 2011). Subspecies caurina is estimated to be in significant decline, at 3.8% per year range-wide and 8.4% per year in Washington State (Dugger et al. 2016). The New Mexico population of subspecies lucida is estimated to be declining at 6% per year (B. Bird in litt. 2011), while the species may have declined by c.50% between 1990 and 2012 in the Sierra Nevada (Tempel et al. 2014b). Although the species appears to be stable in some areas, such as Arizona (B. Bird in litt. 2011), the overall population is suspected to be in decline owing primarily to on-going habitat disturbance by inappropriate silvicultural management including clear-felling and degradation (del Hoyo et al. 1999). There has been no direct estimation of the overall rate of decline, but the species is conservatively assessed as declining at a rate at least approaching the threshold for Vulnerable, and as such is placed in the range 20-29% over 3 generations (c.30 years).


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Canada N Extant Yes
Mexico N Extant Yes
USA N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Mexico Cebadillas
Mexico Chihuahua Wood
Mexico Corredor de Barrancas de la Sierra Madre Occidental.
Mexico Mountain of Valparaiso
Mexico Mountain wood of Carmen
Mexico Papigochi
Mexico Quebradas de Sinaloa, Nayarit y Durango.
Mexico San Antonio Peña Nevada
Mexico Selvas Naryaritas
Mexico Sistem Mountain of the Mountain Occidental Mother
Mexico Table of Macaw
Mexico Tancítaro
USA Canyonlands Area
USA Chiricahua Mountains, Coronado National Forest
USA Grand Canyon National Park- Raptor Migration Points
USA Zion National Park UT20

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Boreal suitable resident
Forest Subtropical/Tropical Dry marginal resident
Forest Temperate major resident
Altitude 0 - 2700 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
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
Climate change & severe weather Droughts Timing Scope Severity Impact
Future Majority (50-90%) Slow, Significant Declines Low Impact: 4
Stresses
Ecosystem degradation, Ecosystem conversion, Reduced reproductive success
Climate change & severe weather Storms & flooding Timing Scope Severity Impact
Future Majority (50-90%) Negligible declines Low Impact: 3
Stresses
Reduced reproductive success
Energy production & mining Oil & gas drilling Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Ecosystem degradation, Ecosystem conversion
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Species disturbance
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Phytophthora ramorum Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Ecosystem degradation, Ecosystem conversion
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Plasmodium relictum Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Species disturbance, Reduced reproductive success
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Strix varia Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Hybridisation, Competition
Invasive and other problematic species, genes & diseases Viral/prion-induced diseases - West Nile Virus (WNV) Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Species mortality
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, Ecosystem conversion
Transportation & service corridors Roads & railroads Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Ecosystem degradation, Ecosystem conversion
Transportation & service corridors Utility & service lines Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Ecosystem degradation, Ecosystem conversion, Species mortality

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Pets Whole Adults and juveniles Wild International Trivial Recent
Pets/display animals, horticulture - - - International Non-trivial Recent

Recommended citation
BirdLife International (2017) Species factsheet: Strix occidentalis. Downloaded from http://www.birdlife.org on 15/12/2017. Recommended citation for factsheets for more than one species: BirdLife International (2017) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/12/2017.