This YouTube video was produced by the American Bird Conservancy.
The Eastern Warbling Vireo (Vireo gilvus) is a quintessential species of spring and summer in the eastern half of North America north of the southern United States. This rather drab bird is often hard to spot, hidden up high among the leaves of tall deciduous trees, but its buoyant, easygoing song — considered by many ornithologists and naturalists to be among the most beautiful in its range — is conspicuous. Males do most of the singing, but females sing as well, an unusual trait among temperate songbirds. Also unusual is this bird’s habit of singing while sitting on the nest.
Eastern Warbling Vireos are frequently parasitized by Brown-Headed Cowbirds, which lay their own eggs in the nests of other species, often resulting in the death of some or all of the host’s young. Cowbirds seem to cue in on this vireo’s habit of singing from the nest, as birds that sing more on the nest are more likely to be parasitized. Female cowbirds are quite crafty, even using the movements of parent birds to determine the location of a nest. The more often a parent uses the same paths to and from the nest, the more likely cowbirds are to find it. However, Eastern Warbling Vireos are remarkably efficient at removing cowbird eggs, often puncturing the offending eggs with their bills before discarding them. Studies of this behavior showed that these vireos seem to recognize cowbird eggs by differences in the pattern of speckles on the shell — and get rid of them 90-100 percent of the time!
Also known as: Vireo Gorjeador Oriental (Spanish), Vireo Cantor (Spanish)
American Bird Conservancy stands up for birds across the Americas. We halt bird extinctions, conserve vital habitats, eliminate key threats, and build the capacity of our partners.
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