Orchard Oriole by Barry Van Dusen
An artist who has created many of our covers, Barry Van Dusen lives in Princeton, Massachusetts, and is well known in the birding world. Barry has illustrated several nature books and pocket guides, and his articles and paintings have been featured in Birding, Bird Watcher’s Digest, and Yankee Magazine as well as Bird Observer. Barry’s interest in nature subjects began in 1982 with an association with the Massachusetts Audubon Society. He has been influenced by the work of European wildlife artists and has adopted their methodology of direct field sketching. Barry teaches workshops at various locations in Massachusetts. For more information, visit Barry’s website at http://www.barryvandusen.com.
The Orchard Oriole (Icterus spurius) is North America’s smallest oriole and one of its most interesting. The adult male has a black head, back, and tail, and a white wing bar and white edges to the flight feathers on its mostly black wings. Its breast, belly, rump, and shoulders are dark russet. It has a short tail and a short bill. The adult female is greenish yellow below, light olive green above, and has two white wing bars. First- and second-year males resemble females but have black throats, and second-year males have some russet body feathers. Adult males are distinctive, but immature males and adult females can be confused with Scott’s and Hooded orioles in various plumages, although Orchard Orioles are smaller. However, the Orchard Oriole’s range does not overlap with the ranges of either of these species. Orchard Orioles are divided into three subspecies. I. s. spurius breeds in the United States and the other two subspecies are restricted to Mexico.
The Orchard Oriole’s breeding range covers most of the eastern half of the United States, from the Rocky Mountains to the East and Gulf coasts. Southward, it extends from eastern Montana, southwest Manitoba, and extreme southeast Saskatchewan to eastern New Mexico, Texas, and along the entire Gulf Coast to northern Florida. The range continues south through Central Mexico and along the central parts of the Mexican Gulf Coast. Eastward, the breeding range extends to the Atlantic coast from Massachusetts and southeast New Hampshire through northern Florida. In the north, the range extends into extreme southern Ontario.
Orchard Orioles winter from central Mexico south through Central America to Northern Colombia and northwest Venezuela. They roost gregariously on the wintering grounds, sometimes with as many as a hundred birds in a single tree. Orchard Orioles arrive on the breeding grounds later than other oriole species and depart earlier, a mechanism that may reduce competition with other orioles for food during the nesting period. They arrive in Massachusetts in late April and May and leave in late July or early August. They are one of our earliest fall migrants.
Orchard Orioles are generally monogamous and produce a single brood, although they occasionally produce a second brood. The song—given by males of all age groups and sometimes by females—is a series of loud, high-pitched clear whistles, followed by lower-pitched notes or phrases, terminating in a downward, slurred note. The song primarily functions to attract a mate because Orchard Orioles are not highly territorial after mating. They also give alarm calls. Both adult and immature males are active on the breeding grounds and sometimes may fight or chase one another. During pair formation, males may chase females. Second-year males are capable of breeding but usually do so in marginal habitat. Females may breed at the age of one year.
Orchard Orioles nest in both suburban and rural areas and generally prefer to be near rivers, lakes, marshes, or floodplains. They readily nest in orchards, gardens, and farmlands as long as scattered trees are available. Many nests are near roads. Orchard Orioles have a high degree of sociality, sometimes nesting semicolonially with as many as 20 nests per tree. They often nest close to kingbirds, whose aggressive behavior may give the orioles some protection against predators and cowbirds. Their sociality is also evident in their tropical wintering areas, where they have been observed, for example, roosting together with seven other species of birds.
The nest cup is usually suspended from terminal twigs or branches. The female builds the nest cup of loosely woven long blades of grass, lined with finer grasses, catkins, and feathers, or bits of human items such as yarn. Orchard Orioles nest and feed lower than Bullock’s and Baltimore orioles, with whom they compete for resources. They also nest later than either of their competitors, thus further reducing competition. The usual clutch is five light blue eggs blotched or spotted with dark colors. The female alone develops a brood patch and she alone incubates the eggs for about two weeks until hatching. Males may guard the nest and feed the incubating female. If a weather event causes nest failure, the pair may renest some distance away. In hot weather, the male may attempt to shade the nest. Both parents feed the young. The chicks fledge after two weeks. Fledged broods are divided between their parents and forage together for four to six weeks. After the males have begun migration, the young forage mostly on fruits with after-hatch-year females until ready to migrate south.
Orchard Orioles glean arthropods from leaves and twigs and forage for grasshoppers in open-field vegetation less than two meters in height. Their food during nesting season is mainly insects and spiders, but they also take berries, seeds, and nectar and peck ripe fruit. They will even use hummingbird feeders. During nesting season, foraging males may drive off immature males. In winter, Orchard Orioles forage mainly on fruit, insects, and nectar. Males may exclude immature males and females from nectar-bearing trees on the wintering grounds.
Orchard Orioles are a common host to cowbirds, and that has been blamed for population declines, particularly in parts of the South. Tower kills, particularly in Florida, have had an adverse impact, as has the eating of eggs and chicks by grackles. Habitat degradation is also a problem. In the twentieth century, Orchard Orioles have been subject to fairly regular population fluctuations although they are widespread and common in some areas. Breeding Bird Survey data show the eastern population as stable, but the central population is showing a significant decline. The American Birds Blue List lists the Orchard Oriole as a Species of Special Concern. Nevertheless, most data suggest that this elegant little oriole will be with us into the indefinite future.