Icterus croconotus

Geographic Range

Orange-backed troupials are native to western and central South America. Two subspecies are recognized, which are Icterus croconotus croconotus and Icterus croconotus strictifrons . Icterus croconotus croconotus occupies a zone starting from the Amazonian range in northwest Brazil and across to southeastern Peru. Icterus croconotus strictifrons is found in Bolivia, northern Argentina, and the state of Mato Grosso in southwestern Brazil.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Orange-backed troupials show an obvious preference for open spaces. They spend most of their time high up in trees or near the edges of rivers and lakes. However, they are generally not found in regions lacking forests. Orange-backed troupials can also be found along roadsides due to recent deforestation. I. c. croconotus prefer swampy areas such as the Amazonia region in northwest Brazil, and is found along the edge of forests. In contrast, I. c. strictifrons is found far from water, occupying dry areas or slightly moist forest edges. For example, this subspecies lives in is the Paraguayan Chaco, a semi-arid region in Paraguay. Orange-backed troupials live at elevations from 500 m to 750 m.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest
• scrub forest scrub forest

• Wetlands
• swamp swamp

• Other Habitat Features
• riparian riparian

Physical Description

Orange-backed troupials are easily identifiable due to their striking orange, black, and white plumage. They have orange backs, and the back of the neck and crown are orange as well. The patch of bare blue skin around their eyes is smaller than that of campo troupials ( Icterus jamacaii ) or Venezuelan troupials ( Icterus icterus ), to which they are related. Juvenile I. c. croconotus in their first year of life is roughly similar in appearance to adults, except for some brown feathers instead of black on the wings and tail. Fledging I. c. croconotus is also similar to adults, but with duller coloring. Orange feathers of juveniles are paler than those of the adults, feathers are brown instead of black, and eyes are darker. Male and female orange-backed troupials are similar to one another, which uncommon among tropical birds. The brightness of feathers is the same, and breast feathers have the same measurements. Orange-backed troupials have a wingspan of 106.5 mm on average.

I. c. croconotus has a black forehead, throat, and tail. The upper breast is black while the lower breast is orange. The nape, sides of the neck, and crown are orange as well. The back is strikingly orange, while the lower back and rump are a more faded orange-yellow. Wings are black and patterned with orange and white. Like campo troupials, I. c. croconotus has pointed throat feathers. Bills are black and eyes are yellow or orange eyes. I. c. strictifrons is similar to I. c. croconotus but has more white patches on its wings and less black on its forehead. A group of I. c. strictifrons found in the Paraguayan Chaco differ slightly in their morphology. Members of this group may have a black band on their backs, less orange on their wings, and a different amount of black on their back and crown.

• Other Physical Features
• homoiothermic

• Sexual Dimorphism
• sexes alike

Reproduction

Like other members of Icterus , orange-backed troupials are thought to be socially monogamous and form lifelong pair bonds.

• Mating System
• monogamous monogamous

Orange-backed troupials breed seasonally, and the timing of the nesting season varies depending on the region. They are obligate nest pirates, stealing and then occupying nests previously built by other species. They make necessary modifications before laying and incubating their eggs. They prefer nests built by yellow-rumped caciques ( Cacicus cela ), which are another species of blackbird. In eastern Ecuador and northern Bolivia, they begin to establish nests between September and November. This is the time when yellow-rumped caciques have finished nesting, which allows orange-backed troupials to move into their abandoned nests. In eastern Peru, they establish their nests during the same time as the nesting season of yellow-rumped caciques, which is July to February. It is common practice for orange-backed troupials to force several female yellow-rumped caciques out from their nests, creating a collection of empty nests to choose from. This technique may be a protective tactic because predators finding a few empty nests are more likely to leave before discovering an orange-backed troupial nest.

Aside from nesting, reproductive behavior of orange-backed troupials is not well understood. However, closely related Venezuelan troupials produce 3 eggs that fledge in 21 to 23 days and travel with their families after leaving the nest. Reproductive behavior of orange-backed troupials is expected to be similar.

• Key Reproductive Features
• seasonal breeding seasonal breeding

Little is known about the extent of parental investment in this species, but both sexes of the closely related species such as Venezuelan troupials are involved in parental care.

• Parental Investment
• male parental care male parental care
• female parental care female parental care
• pre-fertilization
  • provisioning
  • protecting
• pre-hatching/birth
  • provisioning
  • protecting
• pre-weaning/fledging
  • provisioning
  • protecting
• pre-independence
  • provisioning
  • protecting

Lifespan/Longevity

No information is available about the lifespan of the orange-backed troupials.

Behavior

Orange-backed troupials are usually found alone or in mating pairs. Pairs perch up high in trees and perform easily-recognizable duets. While singing, they raise their crown feathers. Their behavior is similar to Venezuelan troupials , but remains under tree cover more often, especially in humid regions.

• Key Behaviors
• arboreal arboreal
• flies
• diurnal diurnal
• solitary solitary
• social social

Home Range

Orange-backed troupials are not known to migrate seasonally or change locations. They are likely territorial to some degree, but the size of the territory or home range is not known.

Communication and Perception

Orange-backed troupials communicate through song. Their most common song has three notes, the first two of which are high notes and the last is low. They also sing the same song with two notes. Their song sounds like "tree-tur" or "cheer-to," and often is proceeded by a soft, introductory note. Mating pairs often sing duets, which are singing the same song in sync with one another. The tunes are harmonized so well that it nearly impossible to distinguish which mate sings which part. Unlike campo troupials , they make little noise aside from their song.

• Communication Channels
• visual visual
• acoustic acoustic

• Other Communication Modes
• mimicry mimicry
• duets duets

Food Habits

The diet of orange-backed troupials is primarily composed of fruit, nectar from flowers, and insects. They like the nectar from the Tabebuia flower. They usually search through dead leaves for insects.

• Primary Diet
• omnivore omnivore

• Animal Foods
• insects

• Plant Foods
• fruit
• nectar

Predation

Some hawks ( Accipiter ) likely attack adults, and a range of birds, mammals and reptiles likely prey on eggs and nestlings.

Ecosystem Roles

As orange-backed troupials search for fruit and ingest nectar, they may contribute to seed dispersal and pollination.

Orange-backed troupials are nest pirates to yellow-rumped caciques . They are hosts for shiny cowbirds ( Molothrus bonariensis ), which lay eggs in their nests in hopes that the parent orange-backed troupials will feed and care for shiny cowbird young.

• Ecosystem Impact
• disperses seeds
• pollinates

Economic Importance for Humans: Positive

Like its close relatives, orange-backed tropuials are commonly captured for cage birds, so they are part of the pet trade.

• Positive Impacts
• pet trade pet trade

Economic Importance for Humans: Negative

There are no known negative impacts of orange-backed troupials on humans.

Conservation Status

Orange-backed troupials have a very large range and relatively secure habitat. Although their population is decreasing and their population is not yet quantified, they are listed as "Least Concern" by the IUCN Red List. They are uncommon to locally common in their range.

Other Comments

Orange-backed troupials are New World orioles, and part of the same genus as the North American Baltimore oriole ( Icterus galbula ). Orange-backed troupials are members of a super species of related taxa, which includes campo troupials from eastern Brazil and the Venezuelan troupials from northern South America. Together these three closely related species make up the troupial complex. During the late 1800s and early 1900s, they were described as three distinct species. Later, they were all grouped together as one species called “troupials" . Since the 1990s, they are once again classified as three separate species.

Additional Links

Encyclopedia of Life

Contributors

Leila Bahmani Kazerooni (author), University of Maryland, Baltimore County, Kevin Omland (editor), University of Maryland, Baltimore County, Catherine Kent (editor), Special Projects, Laura Podzikowski (editor), Special Projects.

References

BirdLife International 2012, 2012. "Icterus croconotus" (On-line). IUCN Red List. Accessed October 10, 2012 at http://www.iucnredlist.org/details/160032483/0 .

Hoffman, C., T. Cronin, K. Omland. 2008. Evolution of Sexual Dichromatism. 1. Convergent Losses of Elaborate Female Coloration in New World Orioles (Icterus spp.). The Auk , 125: 783-785.

Jaramillo, A., P. Burke. 1999. New World Blackbirds: The Icterids . Princeton, New Jersey: Princeton University Press.

Omland, K., S. Lanyon, S. Fritz. 1999. A Molecular Phylogeny of the New World Orioles (Icterus): The Importance of Dense Taxon Sampling. Molecular Phylogenetics and Evolution , 12/2: 235.

Price, J., K. Omland, S. Lanyon. 2009. Losses of female song with changes from tropical to temperate breeding in the New World blackbirds. Proceedings of The Royal Society Biology , 276: 1971.

Restall, R., C. Rodner, M. Lentino. 2006. Birds of Northern South America: An Identification Guide . United States: Yale University Press.

Ridgely, R., G. Tudor. 1989. The Birds of South America . United States of America: University of Texas Press.

Ridgely, R., G. Tudor. 2009. Field Guide to the Songbirds of South America: The Passerines . Austin, TX: University of Texas Press.