Most species of this mainly tropical and subtropical group are resident, but the blue-grey gnatcatcher of the United States and southern Canada migrates south in winter.

[1] These dainty birds are intermediate between Old World warblers and wrens in their structure and habits, moving restlessly through foliage seeking insects.

Many species have distinctive black head patterns (especially males) and long, regularly cocked, black-and-white tails.

This species is characterized by a small, slender body, typically around 10 cm in length, with a long tail, dark gray or bluish-gray plumage, and a faint black line running through its eye.

The California gnatcatcher is an important species in the coastal sage scrub ecosystem, which it relies on for both food and shelter.

The gnatcatcher favors areas with low shrubs and a mix of grasses and wildflowers, where it can easily find insects.

The coastal sage scrub once stretched across much of southern California, from Santa Barbara to San Diego, but has been drastically reduced by urban sprawl and agricultural development.

The gnatcatcher is particularly skilled at foraging in the low shrubbery and in the underbrush, where its small size allows it to maneuver with agility.

As southern California grew, vast areas of coastal sage scrub were converted into housing developments, agriculture, and infrastructure, which resulted in the loss of the gnatcatcher's habitat.

Habitat fragmentation isolates populations, making it difficult for gnatcatchers to find mates and reproduce, which also reduces genetic diversity.

In order to avoid predators, gnatcatchers rely on their excellent camouflage and the dense vegetation of the coastal sage scrub to hide from potential threats.