The California gnatcatcher, Polioptila californica, is a diminutive bird, measuring a mere 10.8 cm in length. This insectivorous avian is a denizen of dense coastal sage scrub growth, and it is a species that has only recently been recognized as distinct from its cousin, the black-tailed gnatcatcher of the Sonoran and Chihuahuan deserts.
The male of the species sports a dusky gray plumage with a distinctive black crown and a slender black beak. Its long, thin tail is also black, adorned with narrow white tips and edges on the underside of the tail feathers. In the winter months, the male's plumage fades to resemble that of the female, who bears a blue-gray crown in place of the male's black. Both sexes are adept at flitting quickly into underbrush, making them a challenge to spot.
The California gnatcatcher is found in a variety of arid environments on the Baja California peninsula, including desert and xeric scrub. At the northwestern limit of its range, in Baja California and California, it is exclusively associated with coastal sage scrub.
This non-migratory bird's range extends from coastal Southern California down through Baja California and Baja California Sur.
Often solitary in nature, the California gnatcatcher may join other birds in winter flocks. It is most commonly observed darting into undergrowth or heard through its distinctive call, reminiscent of a kitten's meow or a rising and falling "zeeeeer, zeeeeer."
The call of the California gnatcatcher is a notable "zeeeeer, zeeeeer," which can be likened to the mew of a kitten, a sound that carries through its scrubland home.
Monogamous pairs of California gnatcatchers tend to their brood of 3β5 eggs in cone-shaped nests. They face the challenge of brood parasitism by brown-headed cowbirds, which lay their eggs in the nests of unsuspecting gnatcatchers.
The diet of this species is composed primarily of small insects and spiders, which they forage for in their scrubland habitat.
The California gnatcatcher is currently classified as Least Concern by the IUCN. However, in the northern part of its range, it has been listed as Threatened due to habitat loss from development. An estimated 70 to 90 percent of coastal sage scrub in the U.S. has been lost. Critical habitat has been designated under the Endangered Species Act, and conservation efforts are ongoing to preserve this species' habitat and prevent further fragmentation of its population.