Black-tailed Gnatcatcher, Polioptila melanura

Black-tailed Gnatcatcher, Polioptila melanura. Photograph taken in the greater Palm Desert area of Riverside County, California, April 2020. Photograph and identification courtesy of Julie McGhee, Oak Hills, California.

Background and Identification

The Black-tailed Gnatcatcher, Polioptila melanura, is a member of the Polioptilidae Family of Gnatcatchers. They are very active songbirds known for their long black tail and agile movements. Generally, Black-tailed Gnatcatchers occur in areas with less than 20 cm (8 inches) of rainfall per year and may build nests several miles away from the nearest water source. In Mexico, they are known as Perlita Colinegra.

Identification of the Black-tailed Gnatcatcher most often begins with its song, because they are usually heard before they are seen. The song of the gnatcatcher is a taunting “zhee-zhee-zhee“, most often sung by male individuals. They are small in stature, and males are larger than females. Adult males are about 10.8 cm (4.25 inches) in length and have an average mass of 5.3 g (0.19 oz). Adult females are about 9.7 cm (3.8 inchers) in length and have an average mass of 5.0 g (0.18 oz). This species is sexually dimorphic in coloration, Adult males are characterized by a bluish-gray plumage with a black cap that extends from the crown to the nape during the breeding season. Females and non-breeding males lack the black cap, sporting a more uniform gray coloration. Both sexes have a long, black tail with white outer feathers, a slender bill, and a white eye ring.

Habitat and Geographical Range

The Black-tailed Gnatcatcher primarily inhabits arid and semi-arid regions, favoring desert scrub, thorn scrub, and mesquite thickets. They are well-adapted to hot, dry environments and can often be found in areas with sparse vegetation and scattered shrubs. They consume insects and small amounts of seasonal fruits and seeds that are commonly grown in these habitats.

Geographically, this species is found in the southwestern United States and northern Mexico. In the U.S., their range includes southern California, Arizona, New Mexico, and parts of Texas. In Mexico, they are found in the coastal regions within the Pacific Slope on the East Coast of Baja California and the West Coast of Sonora and within the central highlands in the States of Chihuahua, Coahuila, and Nuevo León at elevations between 75 m (250 feet) and 900 m (2,950 feet). Black-tailed Gnatcatchers are resident birds, remaining in their range year-round.

Common Misidentifications

The Black-tailed Gnatcatcher can be confused with the similar Blue-gray Gnatcatcher, Polioptila caerulea, which also has a grayish-blue coloration and similar size. However, the Blue-gray Gnatcatcher has a lighter, more uniform gray plumage without the distinct black cap of the male Black-tailed Gnatcatcher. Additionally, the Blue-gray Gnatcatcher’s tail has a more prominent white outer edge compared to the Black-tailed Gnatcatcher.

Conservation Status

From a conservation perspective the Black Gnatcatcher is currently considered to be of Least Concern with stable, widely distributed populations. Their population is relatively widespread within their range, however, habitat loss and degradation due to urban development, agriculture, and other land use pose ongoing threats to their populations. In some areas, fragmentation of their preferred desert scrub habitats is reducing available breeding and foraging areas. Conservation efforts for the Black-tailed Gnatcatcher focus on preserving and managing their desert habitats. This includes protecting large tracts of desert scrub and thorn scrub from development, promoting sustainable land-use practices, and restoring degraded habitats.