The Black-tailed Gnatcatcher (Polioptila melanura) is a small, insectivorous bird which ranges throughout the Sonoran

Sonoran Desert

The Sonoran Desert is a North American desert which straddles part of the United States-Mexico border and covers large parts of the U.S. states of Arizona and California and the northwest Mexican states of Sonora, Baja California, and Baja California Sur. It is one of the largest and hottest...

 and Chihuahuan Desert

Chihuahuan Desert

The Chihuahuan Desert is a desert, and an ecoregion designation, that straddles the U.S.-Mexico border in the central and northern portions of the Mexican Plateau, bordered on the west by the extensive Sierra Madre Occidental range, and overlaying northern portions of the east range, the Sierra...

s of the southwestern United States

Southwestern United States

The Southwestern United States is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah...

 and northern Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

. It is nonmigratory and found in arid desert

Desert

A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...

 areas year-round.

Taxonomy

The Black-tailed Gnatcatcher was described by American ornithologist George Newbold Lawrence

George Newbold Lawrence

George Newbold Lawrence was an American businessman and amateur ornithologist.Lawrence conducted Pacific bird surveys for Spencer Fullerton Baird and John Cassin, and the three men co-authored Birds of North America in 1858.Lawrence left his collection of 8,000 bird skins to the American Museum of...

 in 1857. Meaning 'black-tailed', its specific name is derived from the Ancient Greek

Ancient Greek

Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 melano- 'black' and oura 'tail'.

Description

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-gray, with white underparts, and while it is similar to the Blue-gray Gnatcatcher

Blue-gray Gnatcatcher

The Blue-gray Gnatcatcher, Polioptila caerulea, is a very small songbird.Adult males are blue-grey on the upperparts with white underparts and have a long slender bill, long black tail and an angry black unibrow. Females are less blue without the unibrow...

, 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-gray Gnatcatcher. The best way to tell the two apart is the tail; that of the blue-gray 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.

Behaviour

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-gray Gnatcatcher, the black-tailed variety rarely catches insects in midair.

Breeding

The nest

Bird nest

A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American Robin or Eurasian Blackbird, or the elaborately woven hanging nest of the...

 is an open-cup, built by both sexes, and is typically found in low shrubs less than five feet off the ground. It is constructed of a variety of materials including weed

Weed

A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...

s, grass

Grass

Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

, strips of bark

Bark

Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...

, spider

Spider

Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...

 webs and plant fibers. It is lined with finer, softer matter. Three to five bluish-white eggs

Egg (biology)

An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

 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.

External links

• Black-tailed Gnatcatcher
• Black-tailed Gnatcatcher at birdfriends.com
• Black-tailed Gnatcatcher photo gallery VIREO Photo-High Res--(Close-up)
• Black-tailed Gnatcatcher Photos South Dakota Birds and Birding