Perception Channels: visual ; tactile ; acoustic ; chemical
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
None known.
None known.
Black-tailed Gnatcatchers may be heavily parasitized by Cowbirds in some regions. (Smith 1967)
In general, gnatcatchers feed by gleaning insects from the tips of branches. They mostly do this while perched; however, they are observed to do this while hovering near the branch tips as well. They also eat spiders. They occasionally catch insects in flight by making forays into the air from a perch. Collected specimens have been found with vegetable matter in the stomach, but this must account for only a tiny proportion of food eaten. Black-tailed Gnatcatchers obtain all of their water from the food they eat. (Sibley et al 2001, Smith 1967)
Animal Foods: insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Insectivore )
Black-Tailed Gnatcatchers are found throughout northern and central Mexico and the southwest deserts of the US. (Sibley 2000)
Biogeographic Regions: nearctic (Native )
All gnatcatchers are found in open areas. Black-Tailed Gnatcatchers prefer arid scrublands. They are common in desert washes. (Sibley et al 2001)
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: desert or dune ; chaparral
Black-Tailed Gnatcatchers are small blue-gray birds with a slender bill and tail. They are very active. The breeding male has a black cap which is not present in the basic plumage. Both males and females have a tail that is mostly black, with a small amount of white at the ends of the outer retrices. (Sibley 2000)
Average mass: 5 g.
Average length: 11.4 cm.
Average wingspan: 14 cm.
Other Physical Features: endothermic ; bilateral symmetry
It is thought that Black-tailed Gnatcatchers form monogomous pair bonds that last longer than the breeding season, but the duration of these bonds is not well known.
Mating System: monogamous
Black-Tailed Gnatcatchers form monogamous pair bonds for a given breeding season. The male defends a foraging territory. Numbers given for "number of offspring/eggs per season" are per nest. Double clutching is possible.
Range eggs per season: 2 to 6.
Range time to hatching: 11 to 15 days.
Range fledging age: 10 to 15 days.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous
Both sexes perform nest-building, incubate, and feed during the nestling and fledgling stages. It is common for the parents to raise a second brood shortly after the first. Black-tailed Gnatcatcher chicks are altricial. (Sibley et al 2001, Smith 1967)
Parental Investment: altricial ; male parental care ; female parental care
The Black-Tailed Gnatcatcher (Polioptila Melanura) is one of the smallest song birds of North America. Found most commonly in the Sonoran Desert of the United States and throughout northern and central Mexico. This little song birds habitat consist of desert brush, ravines, dry washes, mesquites but also can be found in low acacia scrub and on open flats of creosote bush.
The Black-Tailed Gnatcatcher diet consists mainly of insects but will occasionally eat vegetable matter. Feeding on a wide variety of small insects such as caterpillars, wasps, ants, flies, moths, small grasshoppers, beetles, spiders and many others. They forage in low brush by picking arthropods from a leaf, branch, or twig and occasionally hovering to catch pray.
Black-tailed Gnatcatchers are considered monogamous. Nest site are located in a low shrub in the fork of two or more branches, usually less than 5 feet above the ground. Nest are built by both sexes and is an open cup shape compacted with plant fibers, grass, weeds, strips of bark, spider webs, and other items, lined with fine materials.
An average clutch is 3-5 eggs. Both parents take turns incubating the eggs for about 14 days. When hatched both parents take turns feeding the nestlings. The young typically leave the nest about 10-15 days after hatching. Black-tailed Gnatcatchers are highly susceptible to Cowbirds who will lay their eggs in nests of this species, and the victim gnatcatcher pairs wind up raising only young cowbirds.
The black-tailed gnatcatcher (Polioptila melanura) is a small, insectivorous bird which ranges throughout the Sonoran and Chihuahuan Deserts of the southwestern United States and northern Mexico. It is nonmigratory and found in arid desert areas year-round.
The black-tailed gnatcatcher was described by American ornithologist George Newbold Lawrence in 1857. Meaning 'black-tailed', its specific name is derived from the Ancient Greek melano- 'black' and oura 'tail'.[2]
The black-tailed gnatcatcher reaches about 4.5 to 5 inches in length, much of it taken up by a long black tail lined with white outer feathers. The body is blue-grey, with white underparts, and while it is similar to the blue-grey gnatcatcher, the two birds are differentiated by the amount of black in the tail feathers. The male has a black cap during the summer that extends to the eyes. Females and winter males, lacking the black cap, are difficult to distinguish from the blue-grey gnatcatcher. The best way to tell the two apart is the tail; that of the blue-grey is mostly white when viewed from below, and the black-tailed is predominantly black underneath. Like other gnatcatchers, it may give harsh, scolding calls while foraging for small insects and spiders in desert shrubs.[3]
Black-tailed gnatcatchers live in pairs all year, defending their territory and foraging in trees and low shrubs for a wide variety of small insects and some spiders. Unlike the blue-grey gnatcatcher, the black-tailed variety rarely catches insects in midair.
The nest is an open-cup, built by both sexes, and is typically found in low shrubs less than five feet off the ground. If available at the nesting site, desert mistletoe, Phoradendron californicum, is often used as the substrate for the nest, which provides nice concealment. It is constructed of a variety of materials including weeds, grass, strips of bark, spider webs and plant fibers. It is lined with finer, softer matter. Three to five bluish-white eggs with red-brown dots are incubated by both parents and take 14 days to hatch. The young are fed by both parents, and leave the nest 10 to 15 days after hatching. Even though cowbirds often lay eggs in this species' nests, and the pair end up raising cowbird young, the black-tailed gnatcatcher population seems to be holding up well.[3]
The black-tailed gnatcatcher (Polioptila melanura) is a small, insectivorous bird which ranges throughout the Sonoran and Chihuahuan Deserts of the southwestern United States and northern Mexico. It is nonmigratory and found in arid desert areas year-round.
