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Baltimore Oriole: Icterus galbula
- University of Iowa Press
- Chapter
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Baltimore Oriole Icterus galbula Spring 2003 was the coldest we had ever experienced in the Big Woods, and the insect population was almost nonexistent. The migratory birds that depend on insects as an important food source consumed more than their usual amount of seeds, suet, oranges, and sugar water at our feeders. In spite of the cold, a tropical sight met my eyes day after day when up to ten Baltimore orioles, five scarlet tanagers, a dozen rose-breasted grosbeaks , and several indigo buntings visited the feeders simultaneously. Once, a multicolored Cape May warbler joined the group. Almost everyone east of the Great Plains is familiar with the Baltimore oriole’s flaming orange and black colors and its clear, melodic spring song that rings from the treetops in open woods, riparian groves, and towns. The male establishes his breeding territory by singing from a prominent perch and countersinging with neighboring males. When the lighter-plumaged female arrives, she too participates in territorial defense, chasing other females out of the area while her mate chases intruding males. Unlike most other songbirds , the female also sings, and countersinging often occurs between mates. In courtship , the male performs a bowing ritual while partly spreading his wings and tail. With her mate in close attendance, the female builds a nest in a tall deciduous tree, often an elm, near the tip of a drooping branch. In May 1998, I watched a nest taking shape in an elm outside my bathroom window. I watched the avian seamstress attach long fibers to a branch and loop them underneath, then take one fiber at a time, push it through one side and pull it through the other until she created a long pouch that swung in the breeze like a cradle. The fibers included grasses, strips of bark, and string that I had placed on branches for her benefit. I couldn’t see the eggs, which she incubated for two weeks, but I eventually saw the four nestlings crying for food from both adults. I later saw the fledglings in drab yellow and brownish plumage visiting the feeders with their parents for sugar water and oranges. After breeding, the orioles no longer sing so often, and their most common vocalization is a harsh rattle. Without knowing the rattle, you might not be aware of their presence . Migration to Mexico and Central and South America begins in late summer. Increasingly , orioles have wintered in the southeastern states where feeders offer oranges, other fruit, and peanut butter mixtures. This species is vulnerable to the absence of elms in which it prefers to nest and deforestation on its wintering grounds in tropical America. Global warming, another cause for concern, may induce orioles to migrate earlier, thus throwing off the timing with certain insects and nectar-producing flowers on which they depend. 97 ...