Coastal California Gnatcatcher (Polioptia californica californica)
The Coastal California Gnatcatcher (CAGN) is a resident bird that is native to Southwestern California and Baja California in coastal sage scrub habitat.
Listing Status
Federally Threatened (USFWS)
CA State Species of Special Concern (CDFW)
VOCALIZATIONS
CAGN are known for their distinctive "mew" call that both sexes exhibit throughout the year. During the breeding season, males often mew from conspicuous perches in varying rates throughout nest stages. Contact churrs are common between a mated pair.
Suitable BREEDING Habitat
CAGN reside in coastal sage scrub habitat that is typically dominated or co-dominated by California sagebrush (Artemisia californica) but can be found in chaparral or grassland/ruderal habitats. In local populations, they can also be found in scrub habitat that is dominated by black sage (Salvia mellifera), white sage (Salvia apiana), quailbush (Atriplex lentiformis), Menzie's golden bush (Isocoma menziesii), or yerba santa (Eriodictyon californium). Nest placement is typically located in a fork that is 1.5 to 4 feet above ground level in a shrub that typically is within a California sagebrush, black sage, white sage, quailbush, yerba santa, California buckwheat (Eriogonum fasiculatum), or bush sunflower (Encelia californica). The birds prefer to nest on slopes of less than 40 percent grade or near small gullies or depressions in the scrub where vegetative cover is between 20-60 percent. Breeding territory size varies between local populations based on topography, density of CAGN pairs, and prey availability but an area as small as 1 acre can support a breeding pair.
Breeding
CAGN typically start laying eggs in mid March; however, in south Orange County, a pair fledged young by mid March, which means they most likely initiated building the second week of February (personal obs., Hill 2015). In central Los Angeles, three CAGN pairs were seen building nests of varying completeness (10%-50%) in the first week of February 2015 (personal obs., Cooper 2015).
Both adult birds participate in building a small cup nest, which can take 2-10 days to complete. Three to four eggs are laid every day and full-time incubation starts upon laying the penultimate egg. Both male and female incubate and the young typically hatch after 14 days. The nestlings typically fledge at 13 days, but can fledge as early as 10 days and as late as 15 days. The adults feed their recent fledglings for approximately 3-4 weeks before the juveniles disperse to nearby unoccupied territories.
Typically, if a pair attempts a second or third brood, they will initiate building between 2-5 weeks after fledgling their first brood; however, it is more often 3-4 weeks will the pairs start nest building. Pairs can fledge up to three successful broods per season and will re-nest quickly if a nest is depredated. One pair in Orange County was observed attending to hatching chicks 3-3.5 weeks after they successfully fledged their first brood. This means the female laid her first egg of her second brood attempt less than 1 week after fledgling her first brood.
Survey Requirements
For survey areas that are within an active Natural Community Conservation Plan (NCCP) jurisdiction, at least three surveys are to be conducted at least one week apart, during any time of the year; however, it is preferred these surveys occur during the breeding season (February 15- August 30).
For survey areas that are not within a NCCP area, two survey options apply. If surveys are to occur between March 15 through June 30, a minimum of 6 surveys, conducted at least one week apart shall occur. Between July 1 through March 14, a minimum of 9 surveys, conducted at least two weeks apart shall occur in order to determine presence/absence. Surveys are to be conducted between 6:00 to 12:00 pm and not during adverse weather conditions. Presence/absence surveys and nest monitoring activities require a USFWS 10(a)1(a) Recovery Permit.
Conservation Status
The CAGN was listed as federally endangered on March 30, 1993. There is currently a petition to delist the species and the USFWS is currently reviewing the petition to delist. The comment period ended on March 2, 2015 and the USFWS will issue a 12-month finding on their final decision presumably by March 2, 2016. The current status of the petition and the associated documents can be found here.
Documents/Links
USFWS CAGN Survey Protocol for Presence/Absence
SDNHM Bird Atlas Species Profile
California Partners in Flight- CAGN Species Profile
Audubon Guide to North American Birds CAGN Species Profile
Molt and Plumage Variation by Age and Sex in the California and Black-tailed Gnatcatchers
References
Mock, P. 2004. California Gnatcatcher (Polioptila californica). In The Coastal Scrub and Chaparral Bird Conservation Plan: a strategy for protecting and managing coastal scrub and chaparral habitats and associated birds in California. California Partners in Flight. http://www.prbo.org/calpif/htmldocs/scrub.html
Unit, Phil. 2012. California Gnatcatcher. In San Diego County Bird Atlas. San Diego Natural History Museum. http://sdplantatlas.org/birdatlas/pdf/California%20Gnatcatcher.pdf
