There are currently three recognized subspecies of California Gnatcatcher based on subtle differecnes in morphology and range (P.c. californica, P.c. pontilis, P.c margaritae; Atwood and Bontrager 2001). The goal of this species account is to report on information of the California Gnatcatcher in the heart of its range (outside of the United States) in Baja California. For a detailed account of the California Gnatcatcher in the United States see Atwood and Bontrager 2001.
Although a large majority of the California Gnatcatcher population is found in Baja California most of the research on the species has focused on only the Coastal California Gnatcatcher subspecies (Polioptila californica californica) in a small portion of it range in Southern California over the last 10-20 years. This is largely a reaction to the explosive human population growth and resultant suburban sprawl within the last 50 years that has dramatically reduced and fragmented the species’ coastal sage scrub habitat in California, ultimately leading to the subspecies gaining federal protection in 1993 as a Threatened species.
In Baja California all three subspecies are found and it is estimated up to 99% of the species’ total population is located south of El Rosario (Salata 1993). The Coastal California Gnatcatcher subspecies (Polioptila californica californica) is found is coastal areas of northwestern Baja California to about a latitude of 30 degree north near Ensenada, Mexico. Land use is not as heavily regulated in Mexico as it is in the United States and much of this subspecies range in Mexico is threatened by uncontrolled urban and agricultural development. The two other subspecies of California Gnatcatcher (pontilis and margaritae) are the least understood subspecies occurring in the central and southern portions of the Baja peninsula where they often sympatrically occur with Black-tailed gnatcatcher (Polioptila melanura) in a wider range of habitat types and elevations.