Wildlife Profile


Orchard Oriole (Icterus spurius)
by Mark Johns

  Wild Facts about the Orchard Oriole

Orchard Orioles are widely distributed breeders east of the Rocky Mountains that show a distinct preference for riparian zones, floodplains, marshes, shorelines of rivers and lakes. Interestingly enough, they also often nest in shade trees, open fields with scattered shrubs and trees and even orchards. The Orchard Oriole is the smallest oriole in North America. They are related to such familiar birds as the Red-winged Blackbird and Eastern Meadowlark. Part of its scientific name spurius translates from Latin to mean illegitimate, which is probably due to its resemblance to the Northern Oriole from early descriptions of the bird. In prime habitat, this species sometimes nests in loose colonies.

History and Status

Found throughout the state as a breeder, the Orchard Oriole is uncommon in the higher elevations of the mountains except as a transient. It seems to be most common in the Coastal Plain. This bird is a Neotropical migrant, but winter stragglers are occasionally found in the Carolinas. Neotropical (New World) migratory birds breed during summer in temperate North America, migrating north each spring from wintering areas, then fly back south to spend the bulk of the year in Mexico, Central or South America, or the Caribbean.   This is a bird of both riparian zones and edges of lakes and ponds, but is also frequently found in open groves of trees, open woodlands and field edges. It often seems to do quite well in habitats with low-density human intrusion, such as farms, pastures and parks. In some areas of the country this species seems to be expanding its range, but in other regions there are declines that are most likely related to loss of orchards, pastures and agricultural land.  Orchard Orioles suffer heavy cowbird parasitism (both Brown-headed and Bronzed Cowbirds) in some areas, and seem to be declining overall in the western part of its range in the United States. In other areas like Missouri and Pennsylvania, Breeding Bird Survey (BBS) data show fluctuating population levels, while Michigan data show significant declines. BBS data for all of North America show significant declines since 1966 for this species.

Description

This is a small, short-tailed oriole with a short bill. The male Orchard Oriole is distinctive, with a black head and tail, dark chestnut breast, belly, rump and part of the shoulder. Its wings are mostly black with narrow white wing-bars. Females and immature males look very similar except that the younger males have a black throat patch. Otherwise, both are greenish yellow below and olive green above, and both have brownish wings with two narrow white wing bars.  Female Baltimore Orioles are easily confused with female Orchard Orioles, but the latter is greener overall in color. As a group, all the mature male orioles of North America are spectacular in coloration.

Habitat and Habits

Nesting occurs in a wide variety of habitat types throughout its range including: rural and surburban areas with scattered trees, pastures or prairies with trees, large planted trees around homes, river valleys, and orchards. Preferred nesting trees include cottonwood (Populus deltoides), ash (Fraxinus spp.), willows (Salix spp.), and red cedar (Juniperus virginiana). Compared to Baltimore Orioles they prefer smaller, shorter trees that are more densely spaced for nesting.  Nests are often attached to the fork of a twig or branch away form the main trunk.  The nest is suspended from the forked twig or branch like that of a Baltimore Oriole, but is not as deep in structure. It is woven over about 6 days and built by the female. Almost half of the time the nests are within 100 feet of water. The female does all the incubation but the male often guards the nest and will feed the female while she incubates.

Orchard Orioles are common hosts of Brown-headed Cowbirds throughout its range, and are also parasitized by Bronzed Cowbirds. In some areas of the country, over half of the Orchard Oriole nests are parasitized by cowbirds. Nests are sometimes abandoned or there is lower fledgling success with cowbird young in the nests.  Their song is a distinctive, loud jumble of clear whistles, somewhat suggestive of a purple finch. There is a slurred wheeer at or near the end of the song. The song usually begins with two or three high-pitched notes. It also has similarities to songs of American Robins, Rose-breasted Grosbeaks and Baltimore Orioles. The black-throated , yellowish male often confuses beginning birders singing from treetops. Males evidently sing quite often on the wintering grounds. Orchard Orioles are only loosely territorial and the primary function of songs may be to attract females.

This bird is mainly insectivorous, but will also eat fruit, small seeds and nectar during summer. A large percent of its diet is grasshoppers and crickets, spiders and beetles. In North America they have been seen feeding on the nectar of flowering trumpet creeper (Campsis radicans). During fall migration they feed heavily on fruits, and on the wintering grounds they commonly consume nectar and pollen. They have been seen feeding at hummingbird feeders. They typically select ripe fruit, which passes through their digestive tract quickly.

Like many Neotropical migrants, these birds mostly migrate at night. Many are trans-gulf migrants, and tend to arrive a bit later than most other oriole species on their breeding grounds in the spring. There are records of birds being killed at TV towers during spring and fall migration.

Range and Distribution

This bird is widely distributed as a breeder east of the Rocky Mountains, slightly into central Canada and well into Mexico. It winters from central Mexico, throughout Central America and into Columbia and Venezuela. This species has been documented living at least 9 years and 7 months.

People Interactions

Occasionally this species may be displaced from orchards that have been sprayed with pesticides or other contaminants. During migration, mortality has been documented from collisions with towers. A big problem is loss or alteration of suitable habitat throughout its range. This species seems tolerant of humans, often nesting close to houses and other structures, and seems to thrive in agricultural and parklike habitats.

Suggested Readings

Conservation and management of neotropical migrant landbirds in the northern Rockies and Great Plains by Dobkin, 1994, Univ. of Idaho Press
The Birder’s Handbook by Ehrlich, Dobkin and Wheye, 1988, Simon and Schuster Inc.


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