Black-capped Gnatcatcher

The Black-capped Gnatcatcher, Polioptila nigriceps, is a diminutive songbird with a poised elegance. Adults typically measure between 10 to 12 cm in length and tip the scales at a mere 5 to 8 grams. Their upperparts are cloaked in a blue-gray hue, while their underparts remain a pristine white. A long, slender bill and a black tail adorned with predominantly white outer feathers are among their distinguishing features. During the breeding season, males don a glossy black cap, adding to their allure.

Identification Tips

To identify the Black-capped Gnatcatcher, look for its blue-gray upperparts and white underparts, along with its long, slender bill. The male's glossy black cap in breeding plumage is a key characteristic. Females and non-breeding males have less bluish-gray upperparts. This species bears a close resemblance to the Black-tailed Gnatcatcher, so careful observation is required for accurate identification.

Habitat

In the northern reaches of its range, the Black-capped Gnatcatcher is found in mesquite thickets close to riparian zones. Further south, it prefers thorn scrub and arid deciduous woodlands. It typically resides at elevations below 500 meters.

Distribution

The Black-capped Gnatcatcher is native to western Mexico, with its range extending from central Sinaloa to Colima. The subspecies P. n. restricta inhabits eastern Sonora to northern Sinaloa and has been known to nest just over the border in southernmost Arizona, USA.

Behaviour

This species is primarily sedentary, though some northern populations may migrate southward after the breeding season. They are active foragers, gleaning foliage and occasionally sallying forth to snatch insects from the air.

Song & Calls

The song of the Black-capped Gnatcatcher is a complex and rambling melody, while its calls include a distinctive "mewing" sound that may be repeated.

Breeding

The breeding season for the Black-capped Gnatcatcher spans from March to June, with fledglings emerging by July. Their nests are small cups made of twigs and spider silk, lined with softer materials, and situated on the branches of low trees or shrubs. Clutches typically consist of four eggs. Instances of parasitism by Brown-headed Cowbirds have been observed.

Similar Species

The Black-capped Gnatcatcher is often confused with the Black-tailed Gnatcatcher due to their similar size and coloration. However, the Black-capped can be distinguished by its glossy black cap in breeding males and its distinct vocalizations.

Diet and Feeding

While the specific diet of the Black-capped Gnatcatcher has not been thoroughly documented, it is presumed to consist of arthropods, similar to other gnatcatchers. They actively forage in trees and shrubs, gleaning foliage and occasionally sallying to catch insects.

Conservation status

The IUCN has classified the Black-capped Gnatcatcher as Least Concern. However, it is noted that both recognized subspecies inhabit ecoregions that are considered to be at serious risk due to agricultural practices and cattle grazing.