Geographic Range
The Jamaican blackbird is an endangered species endemic to its namesake island, Jamaica.
It is restricted to the Blue Mountains in the east and the Cockpit Country in the
west. Evolutionarily, this species is a part of the grackles and allies within the
New World blackbirds. Subsequent phylogenetic research has placed
Nesopsar
in the same group as
Agelaius
and
Dives
, but it still in its own distinct lineage. Although there is not enough information
to reliably estimate the current population size, the species is considered endangered
because of its restricted range and particular habitat needs.
- Biogeographic Regions
- neotropical
- Other Geographic Terms
- island endemic
Habitat
Preferred habitat of the Jamaican blackbird is very specific and the range is highly
fragmented as a result. The Jamaican blackbird is usually confined to areas of above
575 m and is rarely seen in lowland areas. Like many other species, the abundance
and presence of food is indicative of habitat. Its local name “wild pine sergeant”
is indicative of its preference for the epiphytic plant locally called the "wild pine"
(a bromeliad). Optimal Jamaican blackbird habitats are described as being places with
abundant precipitation and heavy epiphytic growth. These include wet limestone forest,
lower montane rainforest, montane mist forest, and elfin forest. However, the species
apparently avoids ridge forest of higher elevation or exposed sites. Jamaican blackbirds
are found in Cockpit Country, John Crow Mountains, and Dolphin Head, which boast wet
limestone forests, and the Port Royal Mountain, Hardwar Gap and, Blue Mountain Peak,
which are montane forests.
- Habitat Regions
- tropical
- terrestrial
- Terrestrial Biomes
- forest
- rainforest
- mountains
Physical Description
The Jamaican blackbird has been described as looking and behaving like a black oriole.
True to this description, it is a medium-sized bird of around 7 to 8 inches long with
entirely black plumage, but with a blue gloss noticeable on the head, upper-parts,
and wing coverts. This blue gloss is entirely absent on the belly. The wing primaries
appear slightly browner than the rest of the body. The adult has a black bill with
dark eyes; its legs and feet are also black. Its bill, although proportional to its
body, is comparatively longer and narrower than those of other
Icteridae
. There is a high probability that this adaptation along with gaping have helped the
bird to more efficiently forage into crevices. Compared to other
blackbirds
, the tail is short and slightly rounded. The Jamaican blackbird is arboreal and thus
should might be expected to show stiffening of the tail feathers as characteristic
of other arboreal climbing birds. However, this is not the case. The tarsometatarsal
length of the Jamaican blackbird is shorter relative to other blackbirds and approaches
the length typical of tree trunk foragers. The juvenile sports a similar coloration
to that of the adult’s but with a looser texture to the plumage. Its plumage also
lacks the indicative blue gloss and instead appears more brown in color. The adult
male is about 5% larger than the female, but their average mass is approximately 41
g. The wing length for the adult male measures 92 to 102 cm while the female measures
94.5 to 101 cm.
- Other Physical Features
- endothermic
- homoiothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
Reproduction
The Jamaican blackbird is socially monogamous. Nesting season lasts from May to July.
Pairs apparently roost a distance of approximately 50 to 100 feet from each other.
- Mating System
- monogamous
The nest is a bulky cup that is built at an average height of 8 m, the lowest height
being 6 m and the highest 11 m above the ground in the lower canopy. The nest site
is not well hidden when compared to those of other blackbirds of the Americas. It
is made of epiphytic fibers, thin dark roots of air plants and rootlets. The nest
is like that of the marsh-nesting blackbirds including
Agelaius
but differs in building materials. Several nests were found in trees that grew slanted
so that the trunk was almost horizontal. Typically, two sparsely spotted and scrawled
eggs are laid.
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- oviparous
The female Jamaican blackbird builds the nest and incubates the eggs as well. On the
other hand, the male often would stand guard near the nest to ward off any possible
intruder.
Males do feed nestlings, although less than the female. However, the male may bring
larger items than the female.
- Parental Investment
- altricial
- male parental care
- female parental care
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- male
-
provisioning
-
pre-weaning/fledging
-
provisioning
- male
- female
-
protecting
- male
- female
-
provisioning
-
pre-independence
-
provisioning
- male
- female
-
protecting
- male
- female
-
provisioning
Lifespan/Longevity
There is little to no information on the longevity of this bird.
Behavior
The species is not as well as known as other island blackbirds. Jamaican blackbirds
are highly territorial and observed to be very particular about its habitat, including
wet montane forests. Instead of the frequency-modulated songs typical of many forest
dwelling birds, Jamaican blackbirds instead have a buzzy song that is common among
blackbirds. They also employ a flight-song display, which is rarely seen in forest-dwelling
birds but is observed among birds that dwell in open spaces. Because of the lack of
a “forest-dwelling” song, Jamaican blackbirds have developed two flight song displays,
which are sung and performed by both sexes. At daybreak, the male is active thirty
to forty minutes before the female. It is at this time that he performs the flight
song throughout his territory while repeating the dzik call. The female will respond
to this by repeating the call as she flies. This is the “patrolling flight." While
performing the “butterfly flight” display, the bird slowly descends from the maximum
altitude and deliberately and slowly flaps its wings. When this is finished, the wings
are closed and the bird dives back into the canopy. The Jamaican blackbird flies above
the forest canopy while singing which again is unusual among woodland birds. The song
flight is performed at irregular intervals. In addition, both sexes of the species
perform three behavioral displays .
There is little information about the territory size but it is estimated to be roughly
500 to 1200 ft. in diameter .
- Key Behaviors
- arboreal
- flies
- diurnal
- crepuscular
- motile
- sedentary
- territorial
Home Range
There is currently no information on the size of the home range.
Communication and Perception
Like other tropical monogamous songbirds, the male and female have a similar number
of vocalizations. The male has seven while the female apparently has six. Although
it has not been previously noted in the published literature, the species does seem
to perform vocal duets.
- Other Communication Modes
- duets
Food Habits
Due to the gaping mechanism adopted by the Jamaican blackbird, it is successful in
filling the feeding niche that has evolved in the absence of trunk foragers and bromeliad
probing. The Jamaican blackbird is also known locally as "wild pine sergeant" because
it forages among bromeliads. These birds also forage amongst lichens, ferns, mosses
and other epiphytes. While foraging, in movements likened to those of a woodpecker
or woodcreeper, it climbs along vines, vertical trunks and moves outwards among branches
near the trunk. The bird has three main foraging behaviors which are probing, gleaning,
and pecking. Probing with their long and narrow bill is most extensively used. The
species feeds on snails, spiders, a wide diversity of insects such as grasshoppers,
beetles, ants, cockroaches, beetle larvae, termites, millipedes, sow bugs, small frogs,
and lizards. The Jamaican blackbird occasionally eats fruit but only rarely eats smaller
berries. Unlike other paired tropical birds, foraging was generally not done in pairs
but alone.
- Primary Diet
-
carnivore
- eats terrestrial vertebrates
- insectivore
- eats non-insect arthropods
- molluscivore
- herbivore
- omnivore
- Animal Foods
- amphibians
- reptiles
- insects
- terrestrial non-insect arthropods
- mollusks
- Plant Foods
- fruit
Predation
There is no information about the predators of the species. The dense and isolated habitat may be seen as an anti-predator adaptation. It is reasonable to believe that other bird species and reptiles are nest predators.
Ecosystem Roles
The Jamaican blackbird has not been extensively studied and ecosystem roles have not been identified. It is safe to assume that the Jamaican blackbird plays some role in seed dispersal. It is also insectivorous but it does not feed among the cultivated areas, thus lowering the possibility of it acting to control agricultural pests.
- Ecosystem Impact
- disperses seeds
Economic Importance for Humans: Positive
The elusiveness of Jamaican blackbirds has made them a must-see on the list of many avid bird watchers as well as ornithologists. This then adds to the bird watching ecotourism industry of the country.
- Positive Impacts
- ecotourism
- research and education
Economic Importance for Humans: Negative
There are no adverse impacts of Jamaican blackbirds on humans.
Conservation Status
Jamaican blackbirds are endangered. The population is estimated to consist of approximately
2,500 to 9,999 individuals. However, more work is needed to better estimate the remaining
number of individuals, identify threats to the population, and protect critical habitats.
Other Comments
Although Jamaican birds are generally sedentary, some pairs are known to migrate to
lower elevations during the winter season.
Additional Links
Contributors
Whitney Phipps (author), University of Maryland, Baltimore County, Kevin Omland (editor), University of Maryland, Baltimore County, Tanya Dewey (editor), University of Michigan-Ann Arbor.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- island endemic
-
animals that live only on an island or set of islands.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- rainforest
-
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
- mountains
-
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
- 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.
- 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.
- monogamous
-
Having one mate at a time.
- 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).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- 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.
- male parental care
-
parental care is carried out by males
- female parental care
-
parental care is carried out by females
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- diurnal
-
- active during the day, 2. lasting for one day.
- crepuscular
-
active at dawn and dusk
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- 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
- visual
-
uses sight to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- 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.
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- molluscivore
-
eats mollusks, members of Phylum Mollusca
- herbivore
-
An animal that eats mainly plants or parts of plants.
- frugivore
-
an animal that mainly eats fruit
- omnivore
-
an animal that mainly eats all kinds of things, including plants and animals
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
References
Barker, K., S. Lanyon, K. Burns, J. Klicka, I. Lovette, A. Powell. 2013. A comprehensive species-level molecular phylogeny of the New World blackbirds (Icteridae). Molecular Phylogenetics and Evolution , 71: 2-19.
Bond, J. 1993. Birds of the West Indies . New York, NY 10003: Houghton Mifflin Company.
Cruz, A. 1978. Adaptive Evolution of the Jamaican Blackbird Nesopsar niggerimus. Ornis Scandinavica (Scandinavian Journal of Orinthology) , 9: 130-137.
Downer, A., R. Sutton. 1990. Birds of Jamaica- A Photographic Field Guide . Cambridge, U.S.A.: Cambridge University Press.
Hoyer, R. 2014. "Nesopsar niggerimus" (On-line). Accessed May 02, 2016 at www.xeno-canto.org .
Jamarillo, A., P. Burke. 1999. New World Blackbirds:The Icterids . 41 William Street, Princeton, NJ 08540: Princeton University Press.
Lanyon, S., K. Omland. 1999. A Molecular Phylogeny of the Blackbirds (Icteridae): Five Lineages Revealed by Cytochrome-B Sequence Data. The Auk , 116: 629-639.
Odom, K., K. Omland, J. Price. 2015. Differentiating the evolution of female song and male-female duets in the New World blackbirds: Can tropical natural history traits explain duet evolution?. Evolution , 69: 839-847.
Orians, G. 1985. Blackbirds of the Americas . Tokyo, Japan: University of Washington Press.
Raffaelle, H., J. Wiley, O. Garrido, A. Keith, J. Raffaelle. 1998. A Guide to the Birds of the West Indies . 41 William Street, Princeton, NJ 08540: Princeton University Press.
Raffaelle, H., J. Wiley, O. Garrido, A. Keith, J. Raffaelle. 2003. Princeton Field Guides: Birds of the West Indies . 41 William Street, Princeton, NJ 08540: Princeton University Press.
Skutch, A. 1996. Orioles, Blackbirds, and Their Kin . Arizona, USA: The University of Arizona Press.
2016. "Important Bird Areas in the Caribbean -Jamaica" (On-line). Birdlife International. Accessed March 04, 2016 at http://www.birdlife.org/datazone/userfiles/file/IBAs/CaribCntryPDFs/jamaica.pdf .