The Blue-gray Gnatcatcher inhabits a wide variety of wooded habitats, but are most often found in moist areas with broad-leaved trees. These birds are active feeders that glean insects off foliage, but will also catch them by hovering and sallying after flushing prey. This species is the only member of the Polioptila genus found in cold temperate regions, and is the only truly migratory gnatcatcher. Some individuals that breed in Central America are mostly residents. The scientific name of the bird basically refers to the blue-gray color of its feathers. Males and females look very similar, and the long tail of this rather small bird is distinctive. The calls and songs are very high in pitch and often hard to detect. Males help out with nest construction, incubation and feeding of young. This species is increasing in both abundance and distribution in North America, and in North Carolina begin nesting early in springtime.
This bird in eastern North America favors a wide range of wooded habitats on its breeding range, and seems to prefer moist areas with broad-leaved trees and is often at or near habitat edges. It is a Neotropical migrant that winters along the western coast of Mexico, parts of Central America and sections of the Caribbean. Neotropical (New World) migratory birds breed during summer in temperate North America, migrating north each spring from wintering areas, then fly back to spend the bulk of the year in Mexico, Central or South America, or the Caribbean. Some birds also winter in southern Florida and along the southeastern coast, and some races are residents year-round in parts of Central America and Mexico.
The breeding range of the Blue-gray Gnatcatcher is expanding northward, especially in eastern North America during the 20th century. There have also been range expansions in the western United States. Breeding season population densities are highest in the southern US, and the floodplains and swamps of this region have the highest breeding densities of all. Breeding Bird Survey results show populations trends on the increase in the eastern US, and this bird is a common breeding season find throughout most of North Carolina.
This is a small, bluish gray (on top), long-tailed bird. In fact, its tail may make-up almost half its total length. It has a fine-tipped bill, obvious white eye rings, white underparts and white outer tail feathers. The tail is often cocked like a wren’s tail and flipped about. To some, it suggests a miniature Northern Mockingbird. It may be confused with Kinglets, but it has a longer bill and tail to give it greater overall length. Kinglets also have obvious wing bars and appear thick-necked.
The Blue-gray Gnatcatcher breeds typically in moist wooded habitats with broad-leaved trees, often at or near habitat edges. Usually it is absent from areas dominated by needle-leaved conifers. It is also found in riparian and swamp forest, upland deciduous woodlands and pine flatwoods with an oak understory. It may be a diurnal migrant, with pairs often arriving at the same time on the breeding grounds in North America.
Songs are complex and continuous jumbles of high-pitched chips and whistles. They are often hard to hear, especially during the breeding season when birds can be high up in trees. Only the males sing, but the calls of males and females appears similar. Calls are heard year round and are high-pitched and often given in short bursts. Evidently some calls are mimetic of other birds.
Birds often pair within hours of first appearing on the breeding grounds and they are one of the earliest nesting small insectivorous songbirds in eastern North America. Pairs seem to select nest sites together, with most nests built well out on side limbs. Typically nests at more than half the height of the nest tree. Both sexes contribute to building the first nest. The nest take about two weeks to build and are cup-like with lots of spider or insect silk decorated with large quantities of lichens.
Blue-gray Gnatcatchers feed mostly near tips of branches in broad-leaved trees and large shrubs. Birds search for food by moving up and down through outer foliage and sometimes along branches toward the trunk, peering with quick head movements. They constantly flick and move their tails, which may flush prey. Small insects and spiders are the chief food items, with the wings of larger insects removed and large prey beaten on a perch before being swallowed.
Range and Distribution
This is a bird common throughout the eastern United States, and also present in parts of the west and southwest. Individuals breeding in Central America, Mexico and Florida are likely residents. Blue-gray Gnatcatchers are present throughout North Carolina as breeders, and some winter along the coast of the Carolinas. Some birds winter in parts of Mexico, Central America, the Caribbean and Florida.
People Interactions
The Blue-gray Gnatcatcher does not seem especially sensitive to human activity around its nest. It is basically a scrub wintering species with a rising population. This suggests that neotropical deforestation is having little current effect on the species. Some biologists have suggested that it has possible forest area requirements, while others maintain that it may have specific microhabitat needs in upland woodlands like canopy gaps.
Suggested Readings
The Bird Life of Texas Vol. 2 by Oberholser, 1974, Univ. Texas Press
Birds of the Carolinas by Potter, Parnell and Teulings, 1980, UNC Press