- 6.7–7.5 in
- 9.1–11.8 in
- 1.1–1.4 oz
- About the size of a Red-winged Blackbird, but slimmer.
- Oriole de Baltimore (French)
- Bosero de Baltimore (Spanish)
- Baltimore Orioles got their name from their bold orange-and-black plumage: they sport the same colors as the heraldic crest of England’s Baltimore family (who also gave their name to Maryland’s largest city).
- Unlike robins and many other fruit-eating birds, Baltimore Orioles seem to prefer only ripe, dark-colored fruit. Orioles seek out the darkest mulberries, the reddest cherries, and the deepest-purple grapes, and will ignore green grapes and yellow cherries even if they are ripe.
- The Baltimore Oriole hybridizes extensively with the Bullock's Oriole where their ranges overlap in the Great Plains. The two species were considered the same for a while and called the Northern Oriole, but in the 1990s, after genetic studies, they were separated again.
- Young male Baltimore Orioles do not molt into bright-orange adult plumage until the fall of their second year. Still, a few first-year males in drab, female-like plumage succeed in attracting a mate and raising young. Females become deeper orange with every molt; some older females are almost as bright orange as males.
- Baltimore Orioles sometimes use their slender beaks to feed in an unusual way, called “gaping”: they stab the closed bill into soft fruits, then open their mouths to cut a juicy swath from which they drink with their brush-covered tongues.
- The orioles of the Americas were named after similar-looking birds in the Old World, but the two groups are not closely related. Orioles of the Old World are in the family Oriolidae, whereas American orioles are in the same family as blackbirds and meadowlarks. Both New and Old World orioles are brightly colored with red, yellow, and black; have long tails and long pointed bills; build hanging, woven nests; and prefer tall trees around open areas.
On their breeding grounds in eastern and east-central North America, you’ll most often find Baltimore Orioles high in leafy deciduous trees, but not in deep forests; they prefer open woodland, forest edge, river banks, and small groves of trees. They also forage for insects and fruits in brush and shrubbery. Baltimore Orioles have adapted well to human settlement and often feed and nest in parks, orchards, and backyards. On their winter range in Central America, Baltimore Orioles occupy open woodlands, gardens, and shade-grown coffee and cacao plantations. They frequently visit flowering trees and vines in search of fruit and nectar.
Baltimore Orioles eat insects, fruit, and nectar. The proportion of each food varies by season: in summer, while breeding and feeding their young, much of the diet consists of insects, which are rich in the proteins needed for growth. In spring and fall, nectar and ripe fruits compose more of the diet; these sugary foods are readily converted into fat, which supplies energy for migration. Baltimore Orioles eat a wide variety of insects, including beetles, crickets, grasshoppers, moths, and flies, as well as spiders, snails, and other small invertebrates. They eat many pest species, including tent caterpillars, gypsy moth caterpillars, fall webworms, spiny elm caterpillars, and the larvae within plant galls. However, orioles can also damage fruit crops, including raspberries, mulberries, cherries, oranges and bananas, and some fruit growers consider these birds a pest.
- Clutch Size
- 3–7 eggs
- Number of Broods
- 1 broods
- Egg Length
- 0.8–1 in
- Egg Width
- 0.6–0.7 in
- Incubation Period
- 11–14 days
- Nestling Period
- 11–14 days
- Egg Description
- Pale grayish or bluish white blotched with brown, black, or lavender.
- Condition at Hatching
- Helpless, eyes closed, with sparse white down.
Baltimore Orioles build remarkable, sock-like hanging nests, woven together from slender fibers. The female weaves the nest, usually 3 to 4 inches deep, with a small opening, 2 to 3 inches wide, on top and a bulging bottom chamber, 3 to 4 inches across, where her eggs will rest. She anchors her nest high in a tree, first hanging long fibers over a small branch, then poking and darting her bill in and out to tangle the hank. While no knots are deliberately tied, soon the random poking has made knots and tangles, and the female brings more fibers to extend, close, and finally line the nest. Construction materials can include grass, strips of grapevine bark, wool, and horsehair, as well as artificial fibers such as cellophane, twine, or fishing line. Females often recycle fibers from an old nest to build a new one. Males occasionally bring nesting material, but don’t help with the weaving. Building the nest takes about a week, but windy or rainy weather may push this as long as 15 days. The nest is built in three stages: first, the female weaves an outer bowl of flexible fibers to provide support. Next, springy fibers are woven into an inner bowl, which maintains the bag-like shape of the nest. Finally, she adds a soft lining of downy fibers and feathers to cushion the eggs and young.
The female chooses a nest site within the territory defended by her mate. She anchors the nest firmly to a fork in the slender upper branches of a tree. Baltimore Orioles often nest in American elms, but will build in other trees, especially maples and cottonwoods. The distinctive nest usually hangs below a branch, but is sometimes anchored along a vertical tree trunk.
Baltimore Orioles are agile feeders that comb the high branches of trees in search of insects, flowers and fruit. They are acrobatic foragers, clambering across twigs, hanging upside down, and fluttering to extend their reach. They also fly out from perches to snatch insects out of the air. Because they forage in the treetops, they are more often seen than heard, but males often sing from conspicuous posts at the tops of trees, where their blazing orange breast attracts the eye. Both males and females may be glimpsed fluttering among the leaves, and come readily to bird feeders supplied with fruit or nectar. Many other birds defend large feeding territories, but orioles defend only the space near their nests, and so you may see several neighboring orioles feeding close to each other. When courting, the male displays by hopping around the female, bowing forward and spreading his wings to reveal his orange back. A receptive female responds by fanning her tail, lowering and fluttering her wings, and making a chattering call.
Baltimore Oriole populations have been declining throughout their range with Canada experiencing over a 3 percent loss per year (resulting in a cumulative loss of 24 percent) between 1966 and 2010, according to the North American Breeding Bird Survey. Partners in Flight estimates the global breeding population at 12 million, with 82 percent spending part of the year in the U.S., 18 percent breeding in Canada, and 24 percent wintering in or migrating through Mexico. They rate a 10 out of 20 on the Continental Concern Score and are not on the 2012 Watch List. Because they breed in North America and winter in Central and South America, Baltimore Orioles are vulnerable to deforestation and habitat loss in many nations; their conservation requires international cooperation. Spraying insecticides onto trees not only kills off Baltimore Orioles’ insect food, but may poison the birds directly. Orioles and many other songbirds migrate at night, when they can become disoriented by lights or rainstorms and crash into tall structures such as skyscrapers and radio towers.
- Rising, J.D., and N.J. Flood. 1998. Baltimore Oriole (Icterus galbula). In The Birds of North America, No. 384. (A. Poole and F. Gill, eds.). The Birds of North America Online, Ithaca, New York.
- Ehrlich, P.R., D.S. Dobkin, and D. Wheye. 1988. The Birder’s Handbook: a Field Guide to the Natural History of North American Birds. Simon and Schuster Inc., New York.
- Lee, C.-T., and A. Birch. 1998. Field identification of female and immature Bullock's and Baltimore Orioles. Birding 30: 282-295.
- Partners in Flight. 2012. Species assessment database.
- Peterson, R.T. 1990. Western Birds: Peterson Field Guides, 3rd ed. Houghton Mifflin, New York.
- Sibley, D.A. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York.
- USGS Patuxent Wildlife Research Center. 2012. North American Breeding Bird Survey 1966–2010 analysis.
Medium- to long-distance migrant. Baltimore Orioles spend summer and winter in entirely different ranges. From early April to late May, flocks arrive in eastern and central North America to breed from Louisiana through central Canada. They start to leave as early as July for wintering grounds in Florida, the Caribbean, Central America, and the northern tip of South America.
Baltimore Orioles seek out ripe fruit. Cut oranges in half and hang them from trees to invite orioles into your yard. Special oriole feeders filled with sugar water supplement the flower nectar that Baltimore Orioles gather. You can even put out small amounts of jelly to attract these nectar-eaters (just don't put out so much that it risks soiling their feathers). Planting bright fruits and nectar-bearing flowers, such as raspberries, crab apples, and trumpet vines, can attract Baltimore Orioles year after year.
Find This Bird
Aim your eyes high when looking for Baltimore Orioles. They’re most often seen perched at the tops of trees or flitting through the upper foliage in search of insects. Listen for their distinctive chatter, which is unlike the call of any other bird where orioles occur. Noisy nestlings may alert you to a nest site high off the ground.