- Other Habitat Features
- Sexual Dimorphism
- sexes alike
- male larger
- Average wingspan
- 125 mm
- 4.92 in
Altamira orioles are seasonally monogamous and may be for life. They are almost always seen in pairs. Breeding begins in the spring and continues through the summer (Jaramillo and Burke, 1999)
- Mating System
Altamira orioles start building their nests as early as March. Generally they only produce one brood per season. However, more southerly populations can produce a second brood. In the event that they brood a second time, a second nest is always built. Nests are hanging baskets, which can be up to 65 cm long, and are built entirely by the female. Nests are built in approximately 3 weeks. Often built at the tip of a yielding branch (usually Mimosa) or a power line; the nests are rarely hidden. Built at an average of 9.3 m from the ground, nests are inaccessible by non-avian predators. Altamira orioles seem to prefer the northwest quadrants of trees, as 9 out of 10 nests have been observed to be built there in a tree's canopy. (Brush, 2005; Jaramillo and Burke, 1999)
In Northern Mexico and Texas, breeding begins in April and lasts through July or August. In Oaxaca, Mexico, breeding starts a little later, in May, and goes through July. The average clutch size is 4.9, but decreases as one moves south. The average incubation period is 14 days. Little is known of the time to fledging. However, the offspring and adults become hostile, chasing away other species of birds for approximately one week after the young leave the nest. (Brush, 2005; Jaramillo and Burke, 1999)
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- Breeding interval
- Altamira orioles breed once or twice a year.
- Breeding season
- Breeding occurs from April to August.
- Average eggs per season
- Average time to hatching
- 14 days
- Average age at sexual or reproductive maturity (female)
- 1 years
- Average age at sexual or reproductive maturity (male)
- 1 years
Young are fed by both males and females about every six to eight minutes during the day. In the event that a pair broods a second time, males will assume most of the feeding responsibility, while females build a second nest. Usually, fecal sacs are removed only by females. (Brush, 2005)
- Parental Investment
There is no published longevity data available for Altamira orioles.
Altamira orioles are usually seen in pairs. They rarely have intraspecific conflicts. Nests are solitary, and are not colonial. However, feeding flocks may be formed in the winter. Altamira orioles fly in jerky and swift movements from perch to perch. Altamira orioles are never seen perching or walking on the ground. (Brush, 2005; Jaramillo and Burke, 1999)
At the Santa Ana Wildlife Refuge, the average distance between nesting sites was 250 m, and individuals were observed to fly 400 m daily, to search for food. (Brush, 2005)
Communication and Perception
Their singing is described as being "a loud, musical, but hesitant series of whistles, reminiscent of an inexperienced human whistler." Raspy, harsh notes may be used as an alarm call, while a quick, nasal "ike" may be used as a contact call between adults and upon arrival at the nest. (Brush, 2005)
Nestlings have a relatively quiet, low pitched begging call. Interestingly, some nestlings in northern Texas apparently produce no sound, perhaps to avoid predation. Males will sometimes develop adult song before they have fully developed plumage. (Brush, 2005)
Altamira orioles also use their keen vision and hearing as their main modes of perception.
- Other Communication Modes
Altamira orioles are predominantly insectivores. However, they will occasionally eat fruit and nectar. It is postulated that they may eat seeds and nuts at some point in the year, due to the formidable size and structure of their bill. Nestlings are mainly fed orthopterans and insect larvae. (Brush, 2005; Jaramillo and Burke, 1999)
- Animal Foods
- Plant Foods
- seeds, grains, and nuts
Altamira orioles have no known predators. Although it is possible that adults are taken by diurnal raptors and that eggs and nestlings might be taken by arboreal predators such as snakes and Bassariscus species. (Brush, 2005; Jaramillo and Burke, 1999)
As they are occasionally frugivorous, Altamira orioles aid in the dispersal of seeds. They are also important as predators of insects. While bronzed cowbirds (Molothrus aeneus) have been observed attempting to parasitize nests, they are almost never successful.
- Ecosystem Impact
- disperses seeds
- bronzed cowbird (Molothrus aeneus)
Economic Importance for Humans: Positive
An attractive bird, Altamira orioles are popular among bird enthusiasts, potentially acting to draw ecotourism to areas they inhabit. As any member of a community within an ecosystem, they are integral to the function of the ecosystem, contributing to its health and beauty.
- Positive Impacts
- research and education
Economic Importance for Humans: Negative
There are no known negative effects of Altamira orioles on humans.
Altamira orioles are not considered threatened, although local populations may be negatively affected by habitat destruction.
Altamira orioles have been integral to some stimulating research concerning the evolution of plumage in the genus Icterus. Dr. Kevin Omland has found several instances of convergent evolution in a variety of plumage characters within the genus, which can be summarized into two plumage types: Altamira plumage type and Baltimore plumage type. Omland and collegues have found that, while Baltimore orioles Icterus galbula, and Altamira orioles have very different plumage, their DNA characteristics demonstrate that they are quite closely related. Furthermore, plumage characteristics that are strikingly similar to that of Altamira orioles can be found in more distantly related species, such as spot-breasted orioles, Icterus pectoralis. (Omland and Lanyon, 2000)
There is a consistent trend within the genus Icterus for males and females of tropical, non-migratory species to share plumage configurations. However, males of most temperate, migratory species have bright plumage characters and females have dull characters. In addition to his other work, Dr. Omland and his graduate students are trying to understand the function of bright female plumage in these and other tropical orioles. For more details on this research, visit the Omland Lab website at: http://www.umbc.edu/biosci/Faculty/OmlandLabWebpage/NewPages/index.htm (Omland and Lanyon, 2000)
Ryan Ihnacik (author), University of Maryland, Baltimore County, Kevin Omland (editor, instructor), University of Maryland, Baltimore County.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
uses sound to communicate
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.
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.
an animal that mainly eats meat
uses smells or other chemicals to communicate
- active during the day, 2. lasting for one day.
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
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.
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.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly insects or spiders.
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).
Having one mate at a time.
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.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
- scrub forest
scrub forests develop in areas that experience dry seasons.
- seasonal breeding
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
uses touch to communicate
Living on the ground.
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- tropical savanna and grassland
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
- temperate grassland
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
uses sight to communicate
Brush, T. 2005. "The Birds of North America Online" (On-line). Accessed March 15, 2005 at http://bna.birds.cornell.edu/BNA/account/Altamira_Oriole/.
Jaramillo, A., P. Burke. 1999. New World Blackbirds: The Icterids. Princeton, New Jersey: Princeton University Press.
Omland, K., S. Lanyon. 2000. Reconstructing plumage evolution in Orioles (Icterus): repeated convergence and reversal in patterns. Evolution, 54: 2119-2133.