Icterus icterus

Geographic Range

Troupials are New World orioles found in northern and central South America. There are three subspecies occupying distinct ranges.

Icterus icterus icterus inhabits the Llanos region in northeastern Colombia and the area between the coast and Amazonas and from Carabobo to Sucre in Venezuela.

Icterus icterus metae is found in the province of Arauca in northwestern Columbia as well as in the Venezuelan state of Apure near the Meta river, after which the subspecies was named.

Icterus icterus ridgwayi inhabits a range from the northeastern tip of Colombia to northwestern Venezuela, and between the coast and Falcón and Lara. Icterus icterus ridgwayi is also found on the islands of Aruba, Curaçao, and Isla Margarita. They have been introduced to the islands of Puerto Rico, St. Thomas, and Bonaire.

While the earlier literature regards troupials as a species or superspecies, with six subspecies, a more recent publication by James Clements, (Supplement to "Birds of the World: A Checklist") states that troupials are a complex of three species with several races each. The three species are: Venezuelan troupials, Icterus icterus , with subspecies I. i. ridgwayi , I. i. icterus , and I. i. metae , Campo troupials, Icterus jamaicaii (previously I. i. jamaicaii ), and orange-backed troupials, Icterus croconotus (previously I. i. croconotus ), with subspecies I. c. croconotus and I. c. strictifrons . These conclusions are based on recent phylogenetic work by Jaramillo et al. (1999) and Omland et. al. (1999).

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Troupials prefer dry edge habitats to those with heavy rainfall, and are typically found in areas of semi-open savanna, dry woodlands, llanos, arid scrub, or gallery forests. Troupials also frequent fruit plantations and gardens with fruit and flowers.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

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

• Other Habitat Features
• suburban suburban
• agricultural agricultural

Physical Description

Troupials are large birds with lengthy, wedge-shaped tails, and long, chisel-like bills. The juvenile plumage is much like adult plumage except for a duller orange color, and a hint of brown on the black feathers. Additionally the naked skin around the eye is a dull blue-grey color instead of the bright blue skin of the adults.

Icterus icterus metae has less black on the back of the body than the other subspecies. The orange neck collar extends further up the back of the head to the hind crown as well as a little further down the nape. Some orange color also extends up the back from the rump, giving the appearance of a patch of orange on the lower back when the wings are closed. Additionally, a band of black bisects the white line running lengthwise down the middle of the closed wing.

Icterus icterus ridgwayi has a similar plumage color pattern to that of I. i. icterus , but differs in that it has a larger build with sturdy legs, and a longer, bulkier bill. Icterus icterus ridgwayi is a darker shade of orange on the island of Aruba compared to individuals from Curaçao.

Adult plumage of I. icterus (including I. i. icterus ) is largely black and orange with the exception of the grey lower mandible. The black coloration starts at the entirely black head and on the top of the bill and extends to cover the entire neck and the upper portion of the breast. The underparts of the bird are orange from the belly to the feathers on the underside of the tail. Icterus icterus icterus also has an orange neck collar, separating the head from the back. The back and shoulders are black, and an orange-yellow color stretches down over the lower back, rump and upper tail coverts. The wings are mostly black with a patch of orange feathers (epaulet) on the upper extreme of the shoulder and a white band running lengthwise in a closed position.

The immature plumage is similar in pattern to that of mature adults, except for a few remaining worn out juvenile feathers. The contrast of worn and fresh feathers is most noticeable at the base of the wing when the wings are in an open position.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Males sing to establish territory. Troupials form monogamous pairs that reportedly stay together throughout the year.

• Mating System
• monogamous monogamous

Nesting season varies by location, lasting from March to September throughout most of their South American range, May to June in Venezuela, and throughout the year in the Antilles. Troupials are well known as nest pirates, seeking and seizing the covered, hanging stick nests of common thornbirds ( Phacellodomus rufifrons ) or great kiskadees ( Pitangus sulphuratus ). As an obligate nest pirate they are one of very few bird species that build no nest of their own. They use their stolen nests for breeding and both members of the breeding pair use individual nests as sleeping chambers. Troupials ultimately use one nest to raise the young. They usually have a clutch size of three eggs, which are white or a whitish pink color with dark spots around the bottom.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• oviparous oviparous

The eggs are incubated for 15 or 16 days and newly hatched troupials are fed equally by both parents. Hatchlings stay in the nest for about 21 to 23 days, during which time they may fall victim to bot flies. After the nesting period, fledglings travel and forage with their parents, and roost in a stolen nest of their own.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female

Lifespan/Longevity

There is no information on the average lifespan of troupials.

Behavior

Troupials steal the nests of other birds and are capable of violent attacks against defending nest residents. They tend to prefer lower nests to those higher in a tree and they may feed on any eggs and nestlings left behind. After obtaining a nest, troupials make modifications like adding their own nest lining or making a wider entrance. A mated pair typically uses more than one nest.

• Key Behaviors
• arboreal arboreal
• flies
• diurnal diurnal
• motile motile
• sedentary sedentary

Home Range

There is little information about the home range of troupials, although year round territories may be common in tropical orioles.

Communication and Perception

Male troupials are best known for singing. They sing most ardently in the early morning hours and continue throughout the day, while females sing less often, often in response to a male's song (Jaramillo and Burke 1999). Despite this difference between the sexes, female song may be common in troupial orioles (J. Price, N. Freidman, K. Omland, unpublished data). Both sexes raise their neck feathers while singing.

Troupials have a simple song consisting of loud, long, repetitive notes, which resemble the call of Baltimore orioles ( Icterus galbula ). Recent research suggests that this similarity of song is due to convergent evolution (Price et al. 2007). Troupial song is difficult to identify in that the simple notes seem to meld together in their slow, careful progression. The song has 2 to 3 individual notes within each repeated phrase and the notes themselves are hoarse whistles of a high or low pitch.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Troupials forage as mated pairs or as a family, consisting of the mated pair and their fledglings. Whether in a pair or as a family group, troupials seldom forage in the vicinity of large flocks. Throughout the breeding season troupials forage for insects in trees and low bushes. On tropical islands, they forage along the ground for fallen fruit. During the non-breeding season, troupials in some areas consume fruit. The fruit of giant cacti for example, may make up the entire diet of troupials when in season. Other fruits eaten include: mango ( Mangifera indica ), kenepa ( Melicoccus bijugatus ), sapodilla ( Achras zapota ), soursop ( Ammona muricata ), papaya ( Carica papaya ), dates ( Phonix dactylifera ), and malphighia cherries ( Malphigia ). Troupials have also been observed feeding at bird feeders, in gardens with fruit trees, and at fruit plantations. (Jaramillo and Burke 1999; Ridgely and Tudor 1989)

• Primary Diet
• omnivore omnivore

• Animal Foods
• insects

• Plant Foods
• fruit

Predation

Nestlings are often parasitized by bot flies ( Oestridae ), which can be fatal for these developing young. Adults are most likely to be killed by larger birds like falcons and accipiter hawks.

Ecosystem Roles

Troupials consume fruit and insects, facilitating seed dispersal and helping control insect populations. They are nest pirates, stealing the nests of common thornbirds (Phacellodomus rufifrons) or great kiskadees (Pitangus sulphuratus).

• Ecosystem Impact
• disperses seeds
• pollinates

Economic Importance for Humans: Positive

As the national bird of Venezuela, troupials promote tourism and national pride. They are kept as cage birds and are often sold throughout their range. They are also valuable research subjects.

• Positive Impacts
• pet trade pet trade
• ecotourism ecotourism
• research and education
• controls pest population

Economic Importance for Humans: Negative

Troupials are known pests on fruit plantations, damaging and devouring valuable crops.

• Negative Impacts
• crop pest

Conservation Status

Troupials face few threats, although they have experienced some population decrease as a result of domestication as a cage bird. In general, they have a very low risk of extinction, especially in Venezuela where they are protected as the national bird.

Other Comments

Of all the species in the genus Icterus genus, troupials are unique. They are larger than average orioles and have some other morphological and behavioral differences as well. First, eye color is different in that troupials have bright yellow eyes whereas the majority of orioles have dark brown eyes. Even more unique is the patch of naked, blue skin surrounding the eye, shared with only a small number of species. The troupial group ( I. icterus and I. jamacaii ) is known to pirate the nests of other birds, and troupials have one of the strongest beaks of any oriole.

Troupial songs set them apart from other orioles because of its bland, two-note simplicity. Unlike other orioles, whose songs are generally recognizable, troupials have a sequence of notes that blend together, making it hard to distinguish separate phrases (Jaramillo and Burke, 1999; Nick Friedman, personal obs.). Troupials have a shaggy bib, a border of pointed feathers around the top of the breast that is smooth on other orioles (Jaramillo and Burke, 1999). In addition, troupials are one of only a few orioles that do not exhibit delayed plumage maturation (DPM) (Kevin Omland, Frode Jacobsen , personal obs.). This means that yearling male troupials have plumage that is the same or very similar to that of adult males. In species that do exhibit DPM, yearling male plumage normally resembles that of adult females. This phenomenon is in fact exaggerated in troupials because the species is monochromatic (males and females have similar bright plumage colors and patterns), as is typical of tropical orioles (Omland and Hofmann 2006).

According to research published by Freeman and Zink (1995), troupials should not be considered members of Icterus . In fact, when Freeman and Zink constructed a phylogenetic tree illustrating the estimated genetic relatedness of 47 species within the subfamily Icterinae , they found that troupials were not members of the oriole clade but an outgroup on their tree, suggesting a distant relationship.

When Omland, Lanyon, and Fritz conducted a follow up genetic investigation in 1999 they found troupials to be more closely related to other orioles. Their phylogenetic tree placed troupials as part of the genus Icterus . Freeman and Zink may have used a contaminated sample.

One further difficulty with troupials, is in defining the species limits. The "troupial group" includes six proposed subspecies: I. i. croconotus , I. i. jamaicaii , I. i. icterus , I. i. metae , and I. i. ridgwayi . Over the years these forms have alternately been re-classified as subspecies and full species. A phylogenetic tree constructed by Omland, Lanyon, and Fritz demonstrates that these subspecies are closely related. According to Monroe and Sibley’s “A World Checklist of Birds,” the name “troupial” only applies to Icterus icterus . This classification most likely includes I. i. icterus , I. i. metae , and I. i. ridgwayi as subspecies. Furthermore Monroe and Sibley group I. i. croconotus and I. i. jamacaii as subspecies under the name Campo oriole. Most recently I. i. jamaicaii , I. i. croconotus , and I. i. strictifrons were recognized as species.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Corey Carter (author), University of Maryland, Baltimore County, Kevin Omland (editor, instructor), University of Maryland, Baltimore County.

References

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

Clements, J. 2003. "Supplement to Birds of the World" (On-line). Accessed May 08, 2007 at http://www.ibispub.com/updates.html .

Ekstrom, J., S. Butchart. 2000. "IUCN Red List of Threatened Species" (On-line). Accessed March 01, 2007 at http://www.iucnredlist.org/search/details.php/54128/summ .

Freeman, S., R. Zink. 1995. A Phylogenetic Study of the Blackbirds Based On Variation in Mitochondrial DNA Restriction Sites. Systematic Biology , 44: 409-420.

Monroe, B., C. Sibley. 1993. A World Checklist of Birds . Ann Arbor, Michigan: Edwards Brothers, Inc..

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: 224-239.

Ridgely, R., G. Tudor. 1989. The Birds of South America: Volume 1 - The Oscine Passerines . Austin, Texas: University of Texas Press.