By Hanna Coy
Geographic Range
Black-Tailed Gnatcatchers are found throughout northern and central Mexico and the southwest deserts of the US. (Sibley 2000)
Habitat
All gnatcatchers are found in open areas. Black-Tailed Gnatcatchers prefer arid scrublands. They are common in desert washes. (Sibley et al 2001)
These animals are found in the following types of habitat:
temperate 
; terrestrial .
Terrestrial Biomes:
desert or dune ; chaparral .
Physical Description
(0.18 oz)
(4.49 in)
(5.51 in)
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)
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
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 systems:
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.
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 .
Behavior
Black-tailed Gnatcatchers are active year-round throughout the desert regions they inhabit. They are less physically active during the summer, but they still may be observed foraging during the hottest periods in shady regions with a cooler microclimate.
They are not philopatric with respect to breeding grounds. When they are not breeding, they tend to wander throughout a region.
Black-tailed Gnatcatchers will dive-bomb another bird that approaches too close to an active nest. (Smith 1967)
Key behaviors:
flies; motile ; migratory ; territorial .
Food Habits
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)
Primary Diet:
carnivore (insectivore ).
Animal Foods:
insects; terrestrial non-insect arthropods.
Ecosystem Roles
Black-tailed Gnatcatchers may be heavily parasitized by Cowbirds in some regions. (Smith 1967)
Economic Importance for Humans: Negative
None known.
Economic Importance for Humans: Positive
None known.
Conservation Status
IUCN Red List: [link]:
Least Concern.
US Migratory Bird Act: [link]:
Protected.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
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For More Information
Find Polioptila melanura information at
Contributors
Hanna Coy (author), University of Arizona.
Jay Taylor (editor), University of Arizona.
