Blue-gray Gnatcatcher (Crum Woods Biodiversity Guide)

Blue-gray Gnatcatcher

Polioptila caerulea

Summary ⁴

The Blue-gray Gnatcatcher (Polioptila caerulea) is a very small songbird.

Polioptila caerulea ⁵

A small (4 ½ inches) songbird, the Blue-gray Gnatcatcher is most easily identified by its blue-gray body, pale breast, and dark tail with white edges. Males in breeding plumage possess faint black eye-stripes which separates them visually from females, which are less adorned. In winter, male and female Blue-gray Gnatcatchers are similar to one another. The Blue-gray Gnatcatcher breeds across much of the United States, southern Canada, Mexico, and northern portions of Central America. In winter, northerly-breeding populations migrate south, spending the winter anywhere from coastal California and the coastal southeastern U.S. south to Central America and the West Indies. Some southerly-breeding populations, particularly those in the tropics, are non-migratory. Blue-gray Gnatcatchers breed in a number of semi-open woodland habitats, particularly in habitats with deciduous trees and often in locations near water. In winter, this species utilizes a variety of tropical and subtropical shrub habitats. As this species’ name suggests, Blue-gray Gnatcatchers primarily eat small insects. In appropriate habitat, Blue-gray Gnatcatchers may be observed flitting through the undergrowth or the lower canopy while searching for insects on leaves or in crevices in bark. Birdwatchers may also listen for this species’ “squeaky” song or high buzzing call, which alert listeners of its presence. Blue-gray Gnatcatchers are primarily active during the day.

Conservation status ⁶

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.

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Habitat ⁷

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 ; rainforest ; scrub forest

Iucn red list assessment ⁸

Red List Category

Least Concern

Red List Criteria

Version

3.1

Year Assessed

2012

Assessor/s

BirdLife International

Reviewer/s

Butchart, S. & Symes, A.

Contributor/s

Justification

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

History

Least Concern (LC)
Least Concern (LC)
Least Concern (LC)
Lower Risk/least concern (LR/lc)
Lower Risk/least concern (LR/lc)
Lower Risk/least concern (LR/lc)

Sources and Credits

(c) Jerry Oldenettel, some rights reserved (CC BY-NC-SA), http://www.flickr.com/photos/7457894@N04/4196627607
(c) Dawn Beattie, some rights reserved (CC BY), http://www.flickr.com/photos/pics4dawn/10828008123/
(c) sergio niebla, some rights reserved (CC BY-SA), https://www.flickr.com/photos/22048801@N03/16324894506/
Adapted by Amanda Carrillo-Perez from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Polioptila_caerulea
(c) Smithsonian Institution, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34818403
(c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31416917
(c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31416911
(c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34663344