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Icterus northropiBahama oriole

By Megan Zimmerman

Geographic Range

Bahama orioles (Icterus northropi) are endemic to the Bahamas Islands and can currently only be found on Andros Island, Bahamas. It was previously deemed Icterus dominicenis northropi because of similarities to other birds of the old Icterus dominicenis species group, however, in 2010 it was separated into its own species. As of 2012, there were between 190 to 254 individuals remaining globally. These birds used to inhabit Abacos Island in the Bahamas as well, however, the population inhabiting Abacos died out in the early 1990’s. (Bond, 1993; Price, 2011; White, 1998)

Habitat

Bahama orioles live at sea level and nest in palm trees in residential areas and broadleaf woodlands. While many of the birds are located on the east coast and prefer residential areas, there are three main populations remaining in North Andros, South Andros and Mangrove Cay. (Lee, 2011)

Physical Description

Males are primarily black on the back, wing and tail, with bright yellow plumage on their breast, vent, side and rump. Juvenile birds have olive coloration above the yellow on their chest. Females are similar to males, with duskier plumage. They are more sexually dimorphic in color than most Caribbean and tropical orioles. These birds are about 20 to 22 cm long. There is no data on the weight of Bahama orioles, but the generalized weight for orioles in the greater Antillean oriole complex is 41 g for males and 36 g for females. (Garrido, et al., 2005; Hofmann, et al., 2008)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • male more colorful
  • Average mass
    36 to 41 g
    oz
  • Range length
    20 to 22 cm
    7.87 to 8.66 in
  • Average wingspan
    9.5 cm
    3.74 in

Reproduction

Orioles are typically socially monogamous. Bahama orioles are known to duet with their partner, this may attract mates or help defend territory. (Jaramillo and Burke, 1999; Lee, 2011)

Their nesting period is typically between May and June, with an average of 3 pale blue eggs per clutch. Bahamas orioles are sexually mature at 2 years of age. Shiny cowbirds, a brood parasite, have had devastating effects on the reproduction attempts of Bahamas orioles. (Jaramillo and Burke, 1999; Lee, 2011; Price, 2011)

  • Breeding interval
    There is currently no information available regarding this species' breeding interval.
  • Breeding season
    This species breeds from February to July.
  • Average eggs per season
    3
  • Average fledging age
    2 weeks
  • Average time to independence
    >2 weeks
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

These birds fledge about 2 weeks after hatching. Both of the parents still assist the young by bringing them food for about two weeks after fledging, slowly weaning the offspring off of assistance. (Jaramillo and Burke, 1999)

Lifespan/Longevity

Bahama orioles have yet to be raised in captivity, so not much is known of their captive lifespan. Likewise, their wild lifespan has not yet been reported.

Behavior

These birds are not shy, they travel in pairs, eating fruit and visiting large flowers. Bahama orioles are known to duet between males and females, a trait only known to about three other species of orioles. This dueting behavior may be the result of sexual conflict over mating, although further research must be conducted. Both sexes duet together, especially during the pre-incubation period. Bahama orioles typically duet within 50 m of their partner and while foraging, building a nest or protecting a nest, which may suggest it is linked to mating behaviors. (Jaramillo and Burke, 1999; Lee, 2011; Price, 2011)

Home Range

The home range size of Bahama orioles has not been reported.

Communication and Perception

The song of Bahama orioles lasts about 2.4 seconds and is comprised of 6 to 11 emphatic whistles. Their main vocalizations include songs, whistles, chits, whines, squawks, chit-whines, chit-whistles and double chit songs. Individuals from the South Andros area tend to whistle more than those located in Mangrove Cay and North Andros. Younger individuals tend to chit more than older individuals. Bahama orioles' duet, a trait not found in many New World orioles. (Del Hoyo, et al., 2011)

  • Other Communication Modes
  • duets

Food Habits

Not much is known of the foraging behaviors of Bahama orioles, although they most likely feed on fruit, nectar and insects. (Lee, 2011)

  • Animal Foods
  • insects
  • Plant Foods
  • fruit
  • nectar

Predation

Predators of Bahama orioles have not been reported.

Ecosystem Roles

Shiny cowbirds are a main contributor to the population decrease of Bahama orioles. These birds are brood parasites and lay their eggs in Bahama orioles' nests. Bahama orioles prey on insects and also feed on fruit and nectar, which may help disperse seeds and pollinate plants. (Jaramillo and Burke, 1999; Lee, 2011; Price, 2011)

  • Ecosystem Impact
  • disperses seeds
  • pollinates
Commensal/Parasitic Species
  • Shiny Cowbird

Economic Importance for Humans: Positive

Bahama orioles provide birding opportunities and recreational enjoyment. Because these birds are critically endangered and island endemic, they are a large draw for birders.

  • Positive Impacts
  • ecotourism
  • research and education

Economic Importance for Humans: Negative

There are currently no known negative economic impacts of Bahama orioles on human populations.

Conservation Status

With less than 300 individuals remaining as of 2013, it is likely that Bahama orioles may go extinct within the next few years. More action is being taken now that Bahama orioles have been re-recognized as their own species rather than as a subspecies of Icterus dominicencis. Soon captive Bahama oriole breeding may be attempted. Shiny cowbirds are a crucial threat to the species. Due to their dependence on palms for nesting, coconut palm yellowing also poses a serious threat. (Jaramillo and Burke, 1999; Lee, 2011; Price, 2011; Price, et al., 2011)

Other Comments

Prior to 1936, Bahama orioles were classified as their own species. James Bond, a prominent 20th century ornithologist (for whom the 007 spy is named after!), published “Birds of the West Indies”, in which he lumped Bahama orioles into greater Antillean orioles along with Cuban orioles, hispaniolan orioles and Puerto Rican orioles. This was later changed when morphological, behavioral and DNA analysis of the four island "subspecies" revealed significant differences between them. The American Ornithologists Union subsequently split these four into separate subspecies in 2010. Because Bahama orioles were grouped into the greater Antillean orioles species complex for so long and because that group is not recognized by the IUCN Red List, the critically endangered status of Bahama orioles went largely unnoticed. (Bond, 1993; Garrido, et al., 2005; Price, et al., 2011; Sturge, et al., 2009)

Contributors

Megan Zimmerman (author), University of Maryland, Baltimore County, Kevin Omland (editor), University of Maryland, Baltimore County, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

diurnal
  1. active during the day, 2. lasting for one day.
duets

to jointly display, usually with sounds in a highly coordinated fashion, at the same time as one other individual of the same species, often a mate

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

male parental care

parental care is carried out by males

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

References

Bond, J. 1993. A Field Guide to the Birds of the West Indies. Boston, Massachusetts: Houghton Mifflin Harcourt.

Del Hoyo, J., A. Elliott, D. Christie. 2011. Handbook of the Birds of the World: Volume 16. Barcelona,Spain: Lynx Edicions.

Garrido, O., J. Wiley, A. Kirkconnell. 2005. The genus Icterus in the West Indies. Ornitologia Neotropical, 16: 449-470.

Hofmann, C., T. Cronin, K. Omland. 2008. Evolution of Sexual Dichromatism 1. Convergent Losses of Elaborate Female Coloration in New World Orioles (Icterus spp.). Auk, 125: 778-789.

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

Kawaha, N., C. Sharp, A. Symes, J. Taylor. 2008. "Birdlife" (On-line). Accessed January 30, 2013 at http://www.birdlife.org/datazone/speciesfactsheet.php?id=32689.

Lee, V. 2011. Vocalization Behavior of the Endangered Bahama Oriole (Icterus northropi): Ontogenetic, Sexual, Temporal, Duetting Pair, and Geographic Variation. Loma Linda, California: Loma Linda University Publications.

Price, M. 2011. Behavioral Ecology, Taxonomy, and Conservation Genetics of the Bahama Oriole (Icterus northropi). Loma Linda, California: Loma Linda University 2011.

Price, M., V. Lee, W. Hayes. 2011. Population Status, habitat dependence, and reproductive ecology of the Bahamas orioles: a critically endangered synanthropic species. Journal of Field Ornithology, 82: 366-378.

Sturge, R., F. Jacobsen, B. Rosensteel, R. Neale, K. Omland. 2009. Colonization of South America from Caribbean Islands Confirmed by Molecular Phylogeny with Increased Taxon Sampling. The Condor, 111: 575-579.

White, J. 1998. A birder's guide to the Bahamas Islands (including Turks and Caicos). Colorado Springs, Colorado: American Birding Association.

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