NATURAL HISTORY

COASTAL CALIFORNIA GNATCATCHER } Polioptila californica californica
FAMILY: Certhiidae

DESCRIPTION: Male coastal California gnatcatchers are dusky gray with a black cap that appears during the spring and summer months. Females have a brown tone to their coloring, gray underparts, and a blue-gray crown. Both sexes have a long, black tail with fine white edging, white eye-rings, and a thin beak. California gnatcatchers are small songbirds, approximately four inches in length.

HABITAT: Coastal California gnatcatchers are found exclusively in coastal sage scrub habitat. Coastal sage scrub is composed of low-growing, drought-deciduous, and succulent plant species such as coastal sagebrush, California buckwheat, prickly pear, cholla, and various species of sage.

RANGE: Generally found at elevations below 3,000 feet, the gnatcatcher ranges from California’s Ventura County south through Los Angeles, Orange, Riverside, San Bernardino, and San Diego counties, extending into Baja California, Mexico.

MIGRATION: Coastal California gnatcatchers are nonmigratory. The longest-documented adult dispersal is less than five miles.

BREEDING: The breeding season for monogamous pairs of coastal California gnatcatchers lasts from late February through August. Low-lying, open-cup nests are built by both parents in areas with a less-than-40-percent slope gradient. Average clutch sizes number four aquamarine-colored eggs, and incubation lasts two weeks. Both parents incubate the eggs, taking half-hour shifts, alternating between incubating the eggs and foraging for food.

LIFE CYCLE: Chicks are blind and uncoordinated at hatching, yet after just two weeks, fledging occurs. They disperse from their natal territory three to four weeks after fledging and have typically have paired up for their own mating by October. They are mature enough to breed by the following spring.

FEEDING: California gnatcatchers are ground and shrub-foraging insectivores. They feed on arthropods, beetles, spiders, leafhoppers, and other small insects. Most of their water intake is obtained through their diet.

THREATS: The main threat to the coastal California gnatcatcher is habitat loss, fragmentation, and degradation. Urban and agricultural development, livestock grazing, invasion of exotic grasses, off-road vehicles, pesticides, and military training activities all contribute to the destruction of gnatcatcher habitat.

POPULATION TREND: Once locally common, coastal California gnatcatchers have experienced widespread habitat destruction and have been driven from most of their former range. By 1997, no more than 2,900 pairs remained in the United States. Only small patches of coastal sage scrub remain, and the majority is privately owned, making species recovery a difficult task.

Photo by B Moose Peterson, USFWS