Blue-gray Gnatcatcher: Migration Monday

Migration Monday is here! Yesterday Dave and I went to Rancocas Nature Center. I read on my E-bird rare bird alert e-mail that someone recently spotted the Pileated Woodpecker there. Since Dave was not with me when I saw it originally, it seemed like a good time to look for it. Unfortunately, we didn’t find the Pileated, but we did see some new spring migrants. So today I wanted to talk about one of our “first of season” birds: the Blue-gray Gnatcatcher.

Blue-gray Gnatcatcher (Polioptila caerulea)


The Blue-gray Gnatcatcher is a tiny, energetic woodland bird. The Blue-gray is smaller than a sparrow, but has a long tail that it pumps up and down while calling and fluttering through the trees. Its upperparts are blue-gray, underparts are grayish-white, and it has  a straight thin bill. It’s tail is mainly black with white underneath. The Blue-gray Gnatcatcher has a white eye ring and a black “v” above their eyes on their forehead.

Blue-gray Gnatcatcher (Image via


Long distance migrant to resident. Summer: breeds from California to the Southwest and the Great Lakes region to the Southeast and to the Northeast. Winters: in Mexico, Southern California and Arizona. Resident of Mexico and the Gulf Coast up to the Carolinas.


Thickets and open woods. Breeding habitat depends on the region. In the West Blue-gray prefer pinyon-juniper woods, scrubby  habitats, oak forests, and chaparral. In the East they live in deciduous forests with maples, oaks, southern pines, or ash. In the winter they usually stay near water in wooded habitats. Breeding habitats continue to  expand northwards.


Mainly insects, but prey depends on the region. Some insects include spiders, treehoppers, caterpillars, adult/larval moths, and many other kinds. Although named “Gnatcatcher”, gnats are not a very large part of a Blue-gray’s diet. They are considered foliage gleaners because they pick insects off leaves in the trees. They may sometimes catch insects in the air.  Before consuming larger prey they will hit the insect against a branch.

Breeding and Nesting:

Males will sing to defend his territory and attract a female. He will also court her by showing her different nest sites to choose from, usually in a deciduous trees. The pair will build a neat, round nest cup together out of small sticks, grass, and other plant fibers. It is wound together by spiderwebs, feathers, or animal hairs. It takes about 2 to 3 weeks to create a 2-3 inch nest. Blue-gray Gnatcatchers will build multiple nests through a breeding season to avoid mite infestations and predation. They will usually reuse materials from previous nests for the new nests.

A Gnatcatcher on its nest (Image by Michele Franz via

Blue-gray Gnatcatchers have 1-2 broods per year with a clutch size (number of eggs) of 3-5 eggs. Both parents will incubate the egg for 11-15 days and feed the chicks. The chicks will leave the nest in 10-15 days after hatching.


Calls: a mewing chee-chee, high trills and whistles. Songs: During nesting and the dawn chorus, simple, short musical phrases. Its morning to mid-afternoon song is more complex with mimic sounds, and sharp whistles and chips.

Fun Facts:

  • The are 4 North American species of Gnatcatchers: Blue-gray, California, Black-tailed, and Black-capped. The Blue-gray is the only common Gnatcatcher outside the Southwest.
  • Blue-gray Gnatcatchers  are nicknamed “The Little Mockingbird”. This is due to the fact that they look similar in appearance and it will put snippets of other bird calls into its songs like a Mockingbird does.
  • They can build up to 7 nests during breeding season.
  • Blue-gray pairs will work together to fight off an intruder in their territories. They are not afraid to attack birds that are much larger than them and will mob predators with other bird species.
(Image via



Author: BirdNation

I am an avid birder, teacher, and nature lover. I primarily go birding in New Jersey and Pennsylvania, but love to travel. I am currently a biology student with interests in conservation biology, ornithology, and environmental sciences. My dream is to go birding in all 50 states.

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