Indigo buntings use vocalizations and visual cues to communicate. Only male indigo buntings sing. Each male has one complex song that it sings, during the breeding season to advertise occupancy of a territory to other males and to attract females. Males may also court females by performing displays, such as the display in which a male struts in circles in front of a female with his wings spread and his head crouched.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Indigo buntings appear to be increasing in geographic range and density. They are protected under the U.S. Migratory Bird Act, but not under CITES or the U.S. Endangered Species Act.
Indigo buntings are occasionally killed for sport and food. They are also a popular cage bird in Europe and Mexico. (Payne, 1992)
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse affects of indigo buntings on humans.
There is apparent aesthetic importance of songbirds like the Indigo bunting to bird watchers and listeners. This brightly colored species is commonly kept as a cage bird (Britannica, 1986).
Perching birds (order Passeriformes) as a group play an important role in the earth's ecosystems. They consume many varieties and amounts of food and serve as food for others and hosts for parasites (Britannica, 1986). Indigo buntings affect the populations of the insects they eat, and help distribute seeds of the plants whose berries they eat. They also host at least one parasite; hippoboscid flies (Payne 1992).
Ecosystem Impact: disperses seeds
During the breeding season, indigo buntings eat small spiders and insects, seeds of grasses and herbs, and berries. Major food items taken include caterpillars, grasshoppers, bugs, beetles, seeds and berries. In winter, indigo buntings eat small seeds, buds, and some insects. Their main food in winter is small seeds of grasses. They also frequent feeders, and eat the seeds of rice in rice fields. Indigo buntings do not appear to drink frequently, and may obtain sufficient water from their diet. (Payne 1992)
Indigo buntings feed alone during the breeding season and in flocks during the winter. They do not appear to store food for later consumption. (Payne 1992)
Animal Foods: insects; terrestrial non-insect arthropods
Plant Foods: seeds, grains, and nuts; fruit
Primary Diet: omnivore
Indigo buntings (Passerina cyanea) breed throughout eastern North America from the Great Plains eastward, south of the coniferous forest region. There are also some breeding populations in the western United States, including Utah, Arizona and California. Indigo buntings winter in the coastal regions of Mexico, Central America, northern South America and the Caribbean.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
Indigo buntings breed in brushy and weedy habitats along the edges of farmed land, woods, road, power lines, railways and riparian habitats. They also breed in clearings in open deciduous woodlands, in weedy or abandoned agricultural fields, and in swamps. During migration they look for open grasslands and leafy trees similar to those in their winter habitat. In winter, indigo buntings choose open habitats, such as weedy fields, citrus orchards, savannas, weedy croplands and low second growth (Payne 1992).
Habitat Regions: temperate ; tropical
Terrestrial Biomes: savanna or grassland ; forest
Wetlands: swamp
Other Habitat Features: agricultural ; riparian
Indigo buntings can live up to 10 years in the wild.
Range lifespan
Status: wild: 10 (high) years.
Average lifespan
Status: wild: 111 months.
Adult male indigo buntings are brilliant blue during the breeding season, with a darker almost purple crown. Females and young are brown with buff wingbars and only a tinge of blue on their tail and shoulders. Indigo buntings are small birds, from 11.5 cm to13 cm long and weighing 12 to 18 g. They have short, conical beaks and black or gray legs and feet. (Payne 1992, Robbins, Bruun and Zim 1983)
Range mass: 12 to 18 g.
Range length: 11.5 to 13 cm.
Sexual Dimorphism: sexes colored or patterned differently; male more colorful
Other Physical Features: endothermic ; bilateral symmetry
Although predation of adult indigo buntings surely occurs, specific predators have not been identified. Brooding females, eggs and young are vulnerable to predation from climbing predators, including raccoons, opossum, red fox, feral cats, blue jays and blue racers.
When a predator approaches a nest, adult buntings may feign injury and make a chip-chip-chip call to distract the predator and lure them away from the nest. They do not mob predators.
Known Predators:
Indigo buntings are socially monogamous. However, pairs only associate until incubation begins, and may switch partners within a single breeding season. Fertilizations outside of a breeding pair are not uncommon and approximately 15% of males have more than one mate.
Males do not sing often in courtship, but they do follow their mate around during the nest building and laying periods, often chasing other males away.
Mating System: monogamous
Indigo buntings breed between May and September, with most activity occurring June through August. They may raise more than one brood per season, and may switch nests or mates between broods. The female chooses the nest site and builds the nest, which may take up to eight days. Nests are built in shrubs in fields or at the edges of woods, roadsides and railways. They are constructed of leaves, grasses, stems and strips of bark. After the nest is complete, the female lays 1 to 4 (usually 3 or 4) white eggs. One egg is laid each day, soon after sunrise. The female begins incubating after the last egg is laid. Incubation lasts for 11 to 14 (usually 12 to 13) days.
The female broods the altricial chicks for the first few days after they hatch. She also feeds the chicks insects and removes their fecal sacs from the nest. The chicks leave the nest 8 to 14 days after hatching, and become independent about 3 weeks after fledging. Indigo buntings are sexually mature at one year old.
Breeding interval: Indigo buntings breed between May and September, with most activity occurring June through August.
Breeding season: Indigo buntings may raise more than one brood per season, and may switch nests or mates between broods.
Range eggs per season: 1 to 4.
Average eggs per season: 3.5.
Range time to hatching: 11 to 14 days.
Average time to hatching: 12-13 days.
Range fledging age: 8 to 14 days.
Average time to independence: 3 weeks.
Range age at sexual or reproductive maturity (female): 1 (low) years.
Range age at sexual or reproductive maturity (male): 1 (low) years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average eggs per season: 4.
The male does not generally help with incubation or raising the chicks. The female chooses the nest site and builds the nest. She broods the altricial chicks for the first few days after they hatch, feeds them insects and removes their fecal sacs from the nest. The chicks leave the nest 8 to 14 days after hatching, and become independent about 3 weeks after fledging.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)
