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Polioptila californica

Brewster, 1881

California Gnatcatcher

G4Apparently Secure (G4G5) Found in 1 roadless area NatureServe Explorer →
G4Apparently SecureGlobal Rank
Least concernIUCN
PSESA Status
Medium - lowThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.103548
Element CodeABPBJ08080
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassAves
OrderPasseriformes
FamilyPolioptilidae
GenusPolioptila
USESAPS
Other Common Names
California gnatcatcher (EN) Gobemoucheron de Californie (FR) Perlita Californiana (ES)
Concept Reference
American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in The Auk]. Also available online: http://www.aou.org/.
Taxonomic Comments
This species formerly was included in P. melanura (AOU 1989, Atwood 1988, 1991). Although morphological studies have led to the recognition of various subspecies (e.g., Atwood 1991, Mellink and Rea 1994), these have been controversial. Moreover, range-wide genetic analyses (Zink et al. 2000, Zink et al. 2013) indicate that northern populations of P. californica are not differentiated from southern populations and that the pattern of genetic variation is inconsistent with the recognition of proposed subspecies.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-07-29
Change Date2008-10-30
Edition Date2008-10-30
Edition AuthorsHammerson, G., D. W. Mehlman, and S. Cannings (2008); rev. R. L. Gundy (2025)
Threat ImpactMedium - low
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences81 - 300
Rank Reasons
This species ranges from southern California through the Baja California peninsula. The population has declined in range and abundance at the northern end of the range in southern California, due mainly to loss and fragmentation of habitat by urban/residential development. In Baja California, where the vast majority of the global population occurs, the species is common and not significantly threatened.
Range Extent Comments
This species is resident in southwestern California, United States and Baja California, México. In southwestern California, it is found in San Diego, Orange, San Bernardino, Los Angeles, and Ventura counties. In México, it is found in most of Baja California Norte and Baja California Sur (including Santa Margarita and Espiritu Santo islands) at appropriate elevations (AOU 1983, Atwood and Bontrager 2001). This species is generally found at elevations below 500 meters. Using Global Biodiversity Information Facility (GBIF) (2025) records from 2000-2025, range extent is estimated to be 248,852 km² (RARECAT 2025).
Occurrences Comments
Applying a 5 km separation distance to GBIF (2025) records from 2000-2025, 175 occurrences are estimated (RARECAT 2025).
Threat Impact Comments
Remaining populations in southern California are highly fragmented by urban development, which has destroyed much coastal sage scrub habitat. Intense housing development and construction or expansion of transportation corridors in Orange, Riverside, and San Diego counties threaten remaining large tracts of habitat (Atwood 1992, Small 1994). Wildfires make habitat unsuitable for years, potentially decades (Small 1994, Winchell and Doherty Jr. 2014, Winchell and Doherty Jr. 2018, Kus 2024).
Ecology & Habitat

Description

A very small, long-tailed bird with a small slender bill; blue-gray above, dull gray below; breeding male has a black cap; narrow white eye ring; tail mostly black (NGS 1983, Peterson 1990).

Diagnostic Characteristics

Differs from black-tailed gnatcatcher in being grayer below and having less white on the underside of the tail. Differs from the blue-gray gnatcatcher in having a less conspicuous eye ring and and dull gray rather than more whitish underparts. See Dunn and Garrett (1987) for detailed treatment of field identification of this and other North American gnatcatchers.

Habitat

Habitats include coastal sagebrush and thorn forest, desert brush, and scrub, especially in mesquite and creosote-bush (AOU 1989), on dry coastal slopes, along washes, and on mesas; areas of low plant growth (about 1 meter high). In California, this gnatcatcher occurs in several distinctive subassociations of the coastal sage scrub plant community, especially those dominated by Artemisia californica (Atwood 1992). Generally it avoids crossing even small areas of unsuitable habitat (Atwood 1992). Nests are in shrubs.

Ecology

Home range may be as small as 0.8 hectares in high quality habitat, as large as 5.6 hectares in inland areas with relatively sparse vegetation (Atwood 1992). Territories generally 1.6 to 4.4 hectares (Atwood 1993).

Reproduction

California: breeds from late February through mid-July, with most initial nesting attempts from mid-March through early April; clutch size averages 3.8; incubation by both sexes, about 14 days; nestling period about 16 days; reproductive success often poor due to predation or parasitism by brown-headed cowbird (Atwood 1992).
Terrestrial Habitats
Shrubland/chaparral
Palustrine Habitats
Riparian
Other Nations (1)
United StatesN2
ProvinceRankNative
CaliforniaSNRYes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentRestricted - smallSerious or 31-70% pop. declineHigh (continuing)
1.1 - Housing & urban areasRestricted - smallSerious or 31-70% pop. declineHigh (continuing)
7 - Natural system modificationsLarge (31-70%)Slight or 1-10% pop. declineHigh (continuing)
7.1 - Fire & fire suppressionLarge (31-70%)Slight or 1-10% pop. declineHigh (continuing)
7.1.1 - Increase in fire frequency/intensityLarge (31-70%)Slight or 1-10% pop. declineHigh (continuing)

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Roadless Areas (1)
California (1)
AreaForestAcres
WildhorseCleveland National Forest1,483
References (38)
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  30. U.S. Fish and Wildlife Service (USFWS). 2000. Proposed determination of critical habitat for the Coastal California Gnatcatcher. Federal Register 65:5946-5976.
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