Polioptila caerulea

Geographic Range

The Blue-gray Gnatcatcher ranges over most of the United States east of the Mississippi, excluding Maine. It can also be found throughout Mexico, Cuba, Texas, Oklahoma, Nevada, Utah, and New Mexico. During the winter, gnatcatchers migrate to Central and South America.

• Biogeographic Regions
• nearctic nearctic
  • native native
• neotropical neotropical
  • native native

Habitat

Gnatcatchers enjoy a wide range of woodland habitats, from shrublands to mature forests. They tend to avoid coniferous forests and concentrate largely along habitat edges. Some of their habitats include floodplain forests, lakeside habitats, pinyon-juniper woodlands, and arid, subtropical shrubbery.

• Terrestrial Biomes
• forest forest
• rainforest rainforest
• scrub forest scrub forest

Physical Description

Blue-gray Gnatcatchers are small birds, with a comparatively long tails. They are bluish-grey above and white below. The color of the bases of the wings blends into the black coloring at the tips. The tail is black with white streaks interspersed. There are prominent thin white rings around each eye.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

Reproduction

Monogamous pairs are formed shortly after the return to the breeding range, in late March or April. There is no evidence as to whether these pairs are lifelong or if new pairs are formed every breeding season. The Gnatctacher nests fairly early for a North American songbird, sometime in the month of April. The nest is built by both the male and female, and takes nearly two weeks to complete. Three to five eggs are layed 5-10 days after construction is finished. The male and female both incubate. After another two weeks the young hatch. Both parents bring food to the young. Although both the male and female contribute to the care of the eggs and hatchlings, they do not interact with one another after incubation begins, seeing each other only in passing. They often fledge a second brood together later in the season.

• Key Reproductive Features
• iteroparous iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Lifespan/Longevity

Behavior

With short mothlike flights, the Blue-gray Gnatcatcher prefers to hop from place to place, either on the groung or along branches. Aggressive behaviors include posturing with the tail raised and audible bill clapping. Gnatcatchers are territorial, displaying these actions toward same-sex intruders. Parents often attack fledglings from the first brood of the summer if they interfere with the rearing of the second brood.

• Key Behaviors
• flies
• motile motile

Communication and Perception

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Gnatcatchers eat mainly small insects and spiders. They search for food by moving up and down through the outer branches of trees or shrubs. Their preferred foods are (in order from highest amount to lowest): Homoptera (cicadas, aphids), Hemiptera, Coleoptera (beetles), Lepidoptera (mothsl, butterflies), Diptera (flies), Hymenoptera (ants, bees, wasps), and Araneae (spiders).

Conservation Status

Gnatcatchers have no special status; however, few data have been collected on the effects of human activity on their populations. Their numbers seem to be rising, indicating that subtropical deforestation is having little effect on these birds, which winter throughout shrub-based habitats in Mexico. Management may be needed for microhabitats in the U.S. (such as stream valleys and canopy openings), rather than large areas.

Other Comments

Gnatcatchers are migratory, with no distinctions in migratory schedules based on age or sex. They leave there wintering sites by mid-March. They remain at their breeding site until shortly after the young have become fully independent, usually in mid-August.

Additional Links

Encyclopedia of Life

Contributors

Jennifer Roof (author), University of Michigan-Ann Arbor.

References

Ellison, Walter G. 1992. The Birds of North America. No. 23. The American Ornithologists' Union.