Blue-gray Gnatcatchers use Tent Caterpillars Silk for Nest Material
They move fast. They are small and gray; blue-gray actually. They arrive early, from Mexico, parts of Central America, and sections of the Caribbean. They search for food by moving up and down through a tree’s outer foliage and sometimes back along branches, peering with quick head movements. They constantly flick their tails, presumably to flush prey. Small insects and spiders are their chief food items. Blue-gray gnatcatchers never seem to sit still.
They take almost two weeks to carefully build their nest, most often far out on side limbs and branches of trees. Their nests are cup shaped with tall sides and often constructed of caterpillar silk or spider webbing, covered with lichens or bark flakes, and lined with grass stems, bark strips, feathers, plant down, or hair. Both males and females are active in building the nest, as seen in the photos here where they are gathering silk from tent caterpillar webs.
Males contribute significantly to incubation, typically of 3 to 5 eggs and lasting for two weeks. The hatchlings are blind, immobile, and featherless. The female generally stays with the hatchlings in the nest, while the male does his share by bringing food for the young. After about ten days the hatchlings leave the nest but the parents continue to feed them for another two weeks. Then the parents will often start again on a second brood before they head south, typically in mid-August. Gnatcatchers are territorial, posturing with their tail raised and making audible bill claps toward same-sex intruders. Parents will attack fledglings from the first brood if they interfere with the rearing of the second brood.
Look for them in moist areas with broad-leaved trees, often at or near habitat edges. These photos were taken in Lebanon, NH at “Two Rivers Park”. Located behind a shopping center, the area is near the intersection of I-89 and I-91 and just south of the mouth of the Mascoma River as it enters the Connecticut River. If you can’t make it there, look for them almost anywhere. They are the most widespread member of its genus in North America. But they are hard to find—they move fast.
