Current view: Data table and detailed info
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
Red List history
| Migratory status |
not a migrant |
Forest dependency |
low |
| Land-mass type |
|
Average mass |
- |
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
Important Bird and Biodiversity Areas (IBA)
Recommended citation
BirdLife International (2024) Species factsheet: Yellow-billed Magpie Pica nutalli. Downloaded from
https://datazone.birdlife.org/species/factsheet/yellow-billed-magpie-pica-nutalli on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/11/2024.
