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Status: Population size: 200,000 Photo by Glen Tepke.

Audubon's Oriole
(Icterus graduacauda)

Much sought after by U.S. birders, Audubon's Oriole has a very restricted range in the U.S. occurring only in the Rio Grande Valley of southern Texas.

Identification
The only yellow oriole to have a black hood and a yellow back, the Audubon's was once named the Black-headed Oriole. It has black wings with white edging and a long black tail. It has the straight, sharp bill of other orioles. The female has the same color pattern but is duller overall. Both sexes sing a long, whistled series of notes that run into each other. It is easily differentiated from the song of the Baltimore Oriole because song is longer, of lower frequency, and the notes sound flat and of the same pitch. Scott's Oriole is similar in appearance, but can be distinguished by its black back.

Distribution and Population Trends
Only occurs in the U.S. in the Rio Grande Valley of southernmost Texas. From southern Texas, its range extends south along the Gulf of Mexico through the Mexican states of Tamaulipas, Nuevo Leon, San Luis Potosi, Veracruz, Hidalgo, and Queretaro. A separate population also occurs along the southwestern border of Mexico in the states of Nayarit, Jalisco, Colima, and Michoacan through Guerrero and Oaxaca. Its population has been described as uncommon in the U.S. and uncommon to common in Mexico. It is a resident of Mexico's Sierra del Abra-Tanchipa IBA and Sierra del Burro IBA.

Ecology
Prefers forest edge habitat, especially with adjoining riparian thickets at elevations above sea level to 2500m. Evergreen, tropical deciduous, pine-oak, and oak forests are preferred. Audubon's is a secretive bird that generally stays in the dense shade of the woods, but will occasionally venture into clearings. They do not migrate, but have been observed wandering north in winter. This species is usually observed as part of a pair year-round. It will join mixed flocks of other orioles, jays, and tanagers, foraging for insects and hackberries.

This species breeds during the rainy season from early April to mid-June and weaves long green grasses or Palmetto fibers to build nests. The cup nests are attached at the top to leafy twigs near the trunk, in contrast to other orioles that place nests at the end of branches. Nests are placed 3-6m off ground. The female incubates a clutch of 3-5 eggs, while the male remains nearby and both individuals call or sing to each other. The young fledge 11 days after hatching. This allows time for pairs to occasionally have two broods a season.

Threats
Habitat loss is the largest overriding threat to the species. Within the U.S. portion of its range, little native habitat was not destroyed or degraded over the last century for agriculture or development. The Bronzed Cowbird is a common brood parasite of this species in Mexico and it appears that Audubon's is a good foster parent. Bronzed Cowbirds have been known to fledge from Audubon's nests. Three nearly full-grown cowbirds have been observed being fed by a pair of Audubon's. One of the reasons this species ranks high on the PIF priority WatchList is because of its extremely small range, especially in the U.S. Disease, extreme weather, and large losses of habitat could have disastrous results on the population. It also suffers from habitat loss due to agricultural practices.

Conservation
In the U.S. portion of the species range there has been extensive work to begun restoring and protecting the remnant forests of the lower Rio Grande Valley of south Texas. The Lower Rio Grande Valley National Wildlife Refuge has been working since 1979 to protect habitat and restore native vegetation. The refuge encompassed more than 90,000 acres in more than 100 separate parcels as of 2002 and is expected to eventually include over 130,000 acres. Texas Parks and Wildlife is developing its World Birding Center in south Texas for launch in 2003 with the goal of engaging both local communities and visitors in state-of-the-art education, restoration and conservation projects, while offering new habitat areas to birdwatchers.

What Can You Do?
Audubon's Important Bird Areas program is a vital tool for the conservation of Audubon's Orioles as well as other species. To learn more about the Important Bird Area programs in Texas and other states, and how you can help, visit: http://www.audubon.org/bird/iba/.

U.S. National Wildlife Refuges like the Lower Rio Grande Valley NWR in south Texas provide essential habitat for Audubon's Orioles, and a great number of other species throughout the U.S. and its territories. Unfortunately, the refuge system is often under-funded during the U.S. government's budgeting process. To learn more about how you can help gain much needed funding for U.S. National Wildlife Refuges, visit: http://www.audubon.org/campaign/refuge_report/

Information on where Audubon's Orioles occur and in what numbers is vital to conserving the species. Help in monitoring this and other species by reporting your sightings to eBird. A project of Audubon and the Cornell Lab of Ornithology, eBird is the world's first comprehensive online bird monitoring program: http://www.audubon.org/bird/ebird.

CIPAMEX, Audubon's BirdLife International partner in Mexico, has an Important Bird Areas program that is working to protect habitat for Audubon's Oriole and many other species. To learn more about Mexico's Important Bird Areas program and how you can help visit: http://132.248.79.80/wwwcampus/cipamex/

Volunteers are crucial to the success of programs that monitor the status of populations of Audubon's Orioles and other bird species. Audubon's Christmas Bird Count (CBC) is one of the longest-running citizen-science monitoring programs in the world and has helped to follow changes in the numbers and distribution of Audubon's Orioles. To learn more about the CBC and how you can participate, visit: http://www.audubon.org/bird/cbc.

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

Skutch, A. F. 1996. Orioles, Blackbirds, and Their Kin: A Natural History. The University of Arizona Press: Tuscon.

Terres, J. K. 1991. The Audubon Society Encyclopedia of North American Birds. Wings Books, New Jersey.