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
- - A1ace

Red List history
Year Category Criteria
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 -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 105,000 medium
Number of locations -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 50000-99999 poor estimated 2014
Population trend Stable 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) - - -
Number of subpopulations - - -
Largest subpopulations - - -
Generation length (yrs) 7.1 - - -

Population justification: The species's population was estimated at c.180,000 individuals in 2003, but is thought to have been reduced by 49% by 2006 (del Hoyo et al. 2009) owing to West Nile Virus. Partners in Flight estimate the population to be 90,000 individuals (Partners in Flight Science Committee 2013). The population now appears to have stopped its decline and may have recovered somewhat (W. Koenig in litt. 2016), thus the population is placed in the band for 50,000-99,999 mature individuals, which is assumed to equate to c.75,000-150,000 individuals in total.

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). The population appeared to reach a low in 2007-2008, and since then has shown signs of recovery, although it was still depleted in 2010/2011 compared to data collected since the late 1950s (W. Koenig in litt. 2012). 

Year by year records from Sauer et al. (2017) show that the species may have continued to decline since the end of the West Nile Virus outbreak, although the decline is deemed non-significant, and instead the species may be considered to be stable. Using the year by year records also means that we can track back to three generations ago (1997) and calculate the population reduction up to 2015. Sauer et al. (2017) show that between 1997 and 2015, the average annual decline was 4.92% (3.00-6.92%), although of course the majority of this was concentrated during the West Nile Virus outbreak. Assuming population stability between 2015 and 2018 would still give a population reduction of 59.7% (42.2-72.5%) over the past 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
Past, Unlikely to Return Whole (>90%) Rapid Declines Past Impact
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 - - - Non-trivial Recent
Pets/display animals, horticulture - - International Non-trivial Recent

Recommended citation
BirdLife International (2019) Species factsheet: Pica nutalli. Downloaded from http://www.birdlife.org on 16/06/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 16/06/2019.