VU
Yellow-billed Magpie Pica nutalli



Taxonomy

Taxonomic note

Pica nutalli (del Hoyo and Collar 2016) was previously listed as P. nuttalli.

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
- - A2ace

Red List history
Year Category Criteria
2021 Vulnerable A2ace
2018 Vulnerable A1ace
2016 Near Threatened A2ae
2014 Near Threatened A2ae
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

Migratory status not a migrant Forest dependency Low
Land mass type Average mass -
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 105,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 400000 poor estimated 2020
Population trend Decreasing estimated -
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) 24 - - -
Number of subpopulations - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 4.3 - - -

Population justification: Partners in Flight (2020) currently estimate the population of Pica nutalli to total 400,000 mature individuals, with the population continuing to decline following the severe impacts of the West Nile Virus.

Trend justification: The species suffered high levels of mortality and a severe population decline owing to an outbreak of West Nile virus (Airola et al. 2007, Crosbie et al. 2008). Following the documented arrival of the virus in California in summer 2003 (Reisen et al. 2004), data have suggested a decline of 42-49% from 2004 to 2006 (Crosbie et al. 2008). Christmas Bird Count (CBC) data from the Lower Sacramento Valley suggest that numbers of this species declined by 48% between 2004/2005 and 2005/2006, with surveyed numbers in 2005/2006 having declined by 38% compared to the previous 10-year average when accounting for the effects of bad weather (Airola et al. 2007). It was thought that the population appeared to reach a low in 2007-08 before showing signs of recovery, however the evidence suggests declines are ongoing. albeit at a lower rate, and the population is still greatly depleted compared to the data collected in the late 1950s (W. Koenig in litt. 2012, Kilpatrick and Wheeler 2019). 

Year by year records from the Breeding Bird Survey (Pardieck et al. 2018) suggest that the species has continued to decline since the end of the West Nile Virus outbreak, although at a lower rate. This data shows that between 2008 and 2019, the average annual decline was 5.64%, which equates to a decline of ~53% across the past three generations (12.9 years). The Audubon Christmas Bird Count suggest a much lower rate of annual decline, 3.12%, which equates to a ~34% reduction across the past three generations (Meehan et al. 2018). To account for the relatively large band of the trend estimate, it is here tentatively assumed that the true rate of decline is in between both extremes and as such the past decline is here placed in the band 30-49% over three generations.

The rate of decline appears to have slowed down considerably in recent years. Between 2016 and 2019, the annual decline amounted to -2.06% per year, although this value is non-significant (Pardieck et al. 2018). Extrapolating over three generations, the rate of past and future decline equates to 24% over three generations.


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

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Arable Land suitable resident
Artificial/Terrestrial Pastureland suitable resident
Artificial/Terrestrial Rural Gardens suitable resident
Forest Temperate suitable non-breeding
Altitude   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%) Unknown Unknown
Stresses
Ecosystem degradation, Ecosystem conversion
Climate change & severe weather Droughts Timing Scope Severity Impact
Past, Likely to Return Majority (50-90%) Causing/Could cause fluctuations Past Impact
Stresses
Indirect ecosystem effects, Species mortality
Invasive and other problematic species, genes & diseases Viral/prion-induced diseases - West Nile Virus (WNV) Timing Scope Severity Impact
Ongoing Whole (>90%) Slow, Significant Declines Medium Impact: 7
Stresses
Species mortality
Pollution Agricultural & forestry effluents - Herbicides and pesticides Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Reduced reproductive success, Species mortality
Residential & commercial development Housing & urban areas Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Ecosystem degradation, Ecosystem conversion

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Pets/display animals, horticulture - - - International Non-trivial Recent
Pets/display animals, horticulture - - International Non-trivial Recent

Recommended citation
BirdLife International (2022) Species factsheet: Pica nutalli. Downloaded from http://www.birdlife.org on 19/08/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 19/08/2022.