Altamira Oriole Life History

Habitat

Habitat Open Woodlands

In the United States, Altamira Orioles are permanent residents in lightly wooded areas of the Rio Grande Valley, Texas. This dry area has been heavily developed, with very little remaining natural habitat, but the species is still fairly common in riparian corridors, thorn forest, wooded parks, well-wooded suburbs near breeding habitat, orchards, farms, and wildlife refuges. Common trees in such habitats include Mexican ash, Mexican leadtree, southern hackberry, black willow, cedar elm, and mesquite (acacia) trees of various species. Farther south, in Mexico and Central America, Altamira Orioles occur in many forested habitats from the coastal plain up to nearly 5,000 feet in elevation. Populations have probably spread into higher foothills as a result of deforestation for agriculture.

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Food

Food Insects

Like other orioles, Altamira Orioles feed mostly on flower nectar, fruits, and insects. They forage in all parts of trees, searching for insects carefully in foliage. They drink nectar either by inserting the bill into a flower (like a hummingbird) or else by puncturing the flower at the base to “rob” the nectar (that is, without helping pollinate the plant). Once they have completed the search of one tree, they fly hurriedly to the next to continue the search. They also take insects from the ground, including ants, grasshoppers, and crickets, along with insect larvae. At feeding stations they consume fresh fruit (oranges, grapes) as well as sunflower seeds. In the wild they eat hackberry and anagua (sandpaper tree) fruits.

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Nesting

Nest Placement

Nest Tree

In southern Texas, females suspend the nest from a branch usually on the northwestern side of a fairly tall tree. Nests are often placed over water or open ground, an average of about 30 feet high.

Nest Description

Females weave long, hanging, pear-shaped bag nests, attaching them to the tips of high branches or sometimes from utility wires. The entrance to the nest is at the top. Nest materials for the exterior include vines, palm frond strips, grasses, flax, bark strips, hair, and roots of epiphytes. The bottom of the nest is padded with plant down, straw, hair, or feathers. Nests range in length from about 1 to just over 2 feet and can be up to 6 inches wide at the widest point.

Nesting Facts

Clutch Size:2-6 eggs
Egg Description:

Pale bluish white with irregular black and purple spots and splotches.

Condition at Hatching:

Helpless.

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Behavior

Behavior Foliage Gleaner

Altamira Orioles form pairs that likely stay together year-round, foraging together and often calling back and forth with nasal contact notes when apart. In the United States, the species does not form flocks (as it does sometimes in Mexico), though several family groups may forage in the same vicinity after the nesting season. No courtship display is known. Females spend up to 3 weeks building a nest, during which time males act as sentinels. Females incubate the eggs and brood the nestlings without help from the male, though males help feed the female and young. On rare occasions, adults threaten other Altamira Orioles that come too close to the nest by pointing the bill skyward, but in general this is not an especially aggressive or territorial species. Altamira Orioles often select nest sites that are near nesting Great Kiskadees or Tropical Kingbirds, possibly so that these more aggressive species will drive away predators or brood parasites such as cowbirds.

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Conservation

Conservation Low Concern

There is no firm information on populations of Altamira Oriole or on its population trends, though it has declined in some parts of its range in Texas, even in national wildlife refuges. The Texas Organization for Endangered Species lists Altamira Oriole as “threatened” in the state. A 2016 Partners in Flight report estimates no more than 500 breeding Altamira Orioles in the United States and rates the species an 11 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. Impacts of brood parasites such as Bronzed and Brown-headed Cowbirds have not been studied, as this species’ nests are difficult to access. Loss of habitats is the chief conservation concern for this species.

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Backyard Tips

Within this species’ range, feeders that offer fresh fruit, hummingbird nectar, or sunflower seeds can attract it. Native plantings that offer fruit or nectar-rich flowers can also bring in Altamira Orioles.

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Credits

Brush, Timothy and Barbara Y. Pleasants. (2005). Altamira Oriole (Icterus gularis), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Rosenberg, K. V., J. A. Kennedy, R. Dettmers, R. P. Ford, D. Reynolds, J. D. Alexander, C. J. Beardmore, P. J. Blancher, R. E. Bogart, G. S. Butcher, A. F. Camfield, A. Couturier, D. W. Demarest, W. E. Easton, J. J. Giocomo, R. H. Keller, A. E. Mini, A. O. Panjabi, D. N. Pashley, T. D. Rich, J. M. Ruth, H. Stabins, J. Stanton, and T. Will (2016). Partners in Flight Landbird Conservation Plan: 2016 Revision for Canada and Continental United States. Partners in Flight Science Committee.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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