NEW WORLD BLACKBIRDS AND ORIOLES: Icteridae

PHYSICAL CHARACTERISTICS

New World blackbirds and orioles (called "icterids" as a group) are physically diverse in coloring, size, and shape. Common colorings are black, dark purple, yellow, brown, and orange. Bill size and shape is also variable—some species like the great-tailed grackle and the meadowlarks have long, curved beaks while others have shorter conical, or cone-shaped, ones. All blackbirds have a unique jaw structure that enables them to force their jaw and bill open, a practice known as gaping that lets them forage, or search for food, more effectively.

GEOGRAPHIC RANGE

As their name implies, New World blackbirds are found throughout North and South America, as are orioles. Some species are also found in the Caribbean.

HABITAT

Grasslands and marshes are popular breeding grounds for icterids, but this diverse family of birds can be found in a number of different biomes.

DIET

Birds in the Icteridae family have a diverse diet, feeding on insects, seeds, fruits, and grains.

BEHAVIOR AND REPRODUCTION

Blackbirds build their bowl-shaped nests in shrubs, trees, and reeds, with the exception of a few species that live in vegetation-free areas that build nests in rock crevices. Orioles build orb-shaped nests constructed of grasses that hang down from a tree branch. One species of Icteridae, the baybird, takes over abandoned nests of other birds. Others are parasitic, meaning that they lay their eggs in another bird's nests for the nest-owner to hatch and fledge, when the young bird is ready to fly on its own.

Depending on the species, male blackbirds have anywhere from one to up to fifteen female mates. Often those male birds that are polygynous (puh-LIJ-uh-nus; have more than one mate) live with a bird population that is mostly female.

BLACKBIRDS, ORIOLES, AND PEOPLE

Because of their large and loud flock sizes and their feeding on agricultural crops such as rice, sunflowers, and corn, many people consider blackbirds and orioles pests.

STRENGTH IN NUMBERS

As the breeding season ends, red-winged blackbirds take to the skies in enormous flocks that can contain tens to hundreds of thousands of birds. They share the skies with other species of blackbirds and starlings, and forage for food together. The size of these flocks helps protect them from predators, animals that hunt them for food, and keeps them protected from the elements. Roosting flocks can be even larger than foraging flocks, and may number over a million birds.

CONSERVATION STATUS

One species—the slender-billed grackle—is extinct, or has died out. Three more species of Icteridae are Critically Endangered, facing an extremely high risk of extinction in the wild; and four are considered Endangered, facing a very high risk of extinction.

BALTIMORE ORIOLE (Icterus galbula): SPECIES ACCOUNTS

Physical characteristics: The Baltimore oriole has a black back, head, and throat and a yellow to orange belly, rump, and shoulders. Wings are black with white-edged feather tips, and the tail has yellow or orange markings. The species is sexually dimorphic in color, meaning that males and females have different color patterns; males are bright orange and jet black, while females are yellow and brown. The female also has two white wingbars, as opposed to one on the male. Average length is 8.75 inches (22.23 centimeters) with a wingspan of 11.5 inches (29.21 centimeters) and a weight of 1.2 ounces (33 grams).

Geographic range: In the summer breeding months the Baltimore oriole can be found in eastern North America, from Alberta to Newfoundland in Canada and from the Dakotas to Maine in the United States. Their range runs south to Texas, Louisiana, and Georgia. Some birds winter in the U.S. in parts of Florida, California, and the Carribean; the rest migrate to Mexico, Central America, and northern South America.

Habitat: Baltimore orioles prefer wooded areas, and build their nests high from the ground. In the fall they migrate south to tropical climates.

Diet: Eats insects (especially caterpillars), berries, and fruit. They also will feed on human-provided foods such as suet, jams and jellies, and sugar-water in hummingbird feeders.

Behavior and reproduction: Baltimore orioles breed in monogamous (muh-NAH-guh-mus) pairs, with one male and one female. The male attracts a mate by singing, chasing, and showing off his plumage. Females weave basket-like nests of grass and plant and human-made fibers that hang from tree branches. They lay eggs in average clutches of four to five eggs, which hatch in approximately two weeks. Both mother and father feed the hatchlings until they leave the nest after two weeks.

Baltimore orioles and people: Because of their bright plumage and loud, clear song, Baltimore orioles are considered desirable neighbors to many people. The birds also help control the population of insects that are destructive to vegetation, like gypsy moth caterpillars and grasshoppers.

Conservation status: Baltimore orioles are not threatened. ∎

RED-WINGED BLACKBIRD (Agelaius phoeniceus): SPECIES ACCOUNTS

Physical characteristics: The male red-winged blackbird can be identified by the yellow-bordered red patches on the shoulder portion of the wing. While the adult male is a glossy black with black bill and feet, the adult female is streaked or striped with shades of brown and white. She is marked with a white stripe across her eye, a buff colored throat, and a faint orange patch on her shoulder. Birds don't attain their full adult coloring until they are three years old. Average size is 8.75 inches (22.23 centimeters) in length with a wingspan of 13 inches (33.02 centimeters) and a weight of 1.8 ounces (52 grams).

Geographic range: Like other New World blackbirds, the red-winged blackbird has an extensive North and South American range. The birds breed throughout Canada, the entire contiguous United States, and in southeastern Alaska all the way southward through Central America. They spend their winters as far north as southern Canada and south through Costa Rica. Some southern subspecies, population groups, are non-migratory.

Habitat: During breeding season red-winged blackbirds favor areas with tall vegetation such as marshes or grassland. They weave their nests into reeds or other vegetation to prevent access by predators. Wetlands also provide ample insects for feeding. In nonbreeding season, they descend on agricultural crops in large flocks.

Diet: Insects are the red-winged blackbird's staple during the summer months, but after breeding season they forage for grains and seeds.

Behavior and reproduction: Red-winged blackbird males mate with multiple females. Males are very territorial and will vigorously defend their space. Females select their mates based on the quality of the territory they have secured for nesting. Behaviors such as chasing, singing, and a "song spread" (in which the male sings loudly, spreads his wings, and puffs out his brightly colored epaulets, or shoulder feathers) are used by male birds to attract a mate. Interestingly, these same behaviors are also used to defend breeding territory from other males once it has been established.

The species travels and roosts with other types of blackbirds and starlings when they are not breeding, in flocks that can sometimes number in the hundreds of thousands.

Red-winged blackbirds and people: Because of their love of grains, rice, and seeds, the red-winged blackbird is considered a nuisance to many farmers. Crops for human and livestock consumption are frequently scavenged by large flocks of blackbirds. The United States Department of Agriculture estimates that sunflower growers in both North and South Dakota lose an estimated $4 to 7 million annually to blackbird damage to their crops. The USDA has used several pilot programs to try and reduce crop damage in recent years, including avicide (bird poisoning) programs, herbicide destruction of desirable red-winged blackbird habitat (such as cattail stands), and use of protective aerial lines over crops.

Conservation status: Despite concerted efforts to reduce their population, the red-winged blackbird continues to thrive in abundance. ∎

BAYWING (Agelaioides badius): SPECIES ACCOUNTS

Physical characteristics: The baywing, sometimes called the baywinged cowbird, is a small olive-gray bird. Wings are chestnut with black markings, and the bill, feet, and tail are black as well. Average size is about 7 inches (18 centimeters) in length and 1.4 to 1.8 ounces (41 to 50 grams).

Geographic range: A year-round resident of South America, the baywing is found in parts of Bolivia and Argentina, northeastern Brazil, Paraguay, and Uruguay.

Habitat: Baywings are found at higher altitudes, up to 9,500 feet (2,880 meters), and favor scrub or wooded terrain.

Diet: Baywings eat primarily insects.

Behavior and reproduction: Instead of building their own nests, baywings typically take over abandoned nests of other birds (although some will either build their own cup-shaped nests or dwell in woodpecker holes). They are frequent victims of screaming cowbirds, a brood parasite species that lays their eggs in other birds' nests for incubation and fledging. It is thought that baywings lay clutches of four to five eggs.

Baywings and people: Baywings are not considered agricultural pests and enjoy a harmonious relationship with people.

Conservation status: Baywings are not a threatened species. ∎

FOR MORE INFORMATION

Books:

George, Phillip Brandt. "Blackbirds, Orioles." In Reference Atlas to the Birds of North America, edited by Mel Baughman. Washington, DC: National Geographic Press, 2003.

Jaramillo, Alvaro, and Peter Burke. New World Blackbirds: The Icterids. Princeton, NJ: Princeton University Press, 1999.

Sibley, David Allen. National Audubon Society: The Sibley Guide to Birds. New York: Alfred A. Knopf, 2000.

Periodicals:

Harrison, George. "The Lord and Master: The Flashy Red-winged Blackbird is a Joyful Songster, a Master Weaver, and One of Our Most Easily Recognized Birds." Birder's World (February 2003): 42–5.

Web sites:

Cornell Lab of Ornithology. "Baltimore Oriole." All About Birds. http://birds.cornell.edu/programs/AllAboutBirds/BirdGuide/Baltimore_Orile_tl.html (accessed on May 28, 2004).

Cornell Lab of Ornithology. "Red-winged Blackbird." All About Birds. http://birds.cornell.edu/programs/AllAboutBirds/BirdGuide/Red-winged_Blackbird.html (accessed on May 28, 2004).

United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services. "Development and Evaluation of Management Techniques for Reducing Blackbird Damage to Ripening Sunflower Crops and to Feedlots." National Wildlife Research Center. http://www.aphis.usda.gov/ws/nwrc/research/sunflowers/ (accessed on May 29, 2004).