Bullock's oriole (''Icterus bullockii'') is a small
New World blackbird
Icterids () or New World blackbirds make up a family, the Icteridae (), of small to medium-sized, often colorful, New World passerine birds. Most species have black as a predominant plumage color, often enlivened by yellow, orange, or red. The ...
. At one time, this species and the
Baltimore oriole
The Baltimore oriole (''Icterus galbula'') is a small icterid blackbird common in eastern North America as a migratory breeding bird. It received its name from the resemblance of the male's colors to those on the coat-of-arms of 17th century ...
were considered to be a single species, the
northern oriole
The northern oriole (''Icterus galbula''), considered a species of North American bird from 1973 to 1995, brought together the eastern Baltimore oriole
The Baltimore oriole (''Icterus galbula'') is a small icterid blackbird common in eastern ...
. This bird is named after
William Bullock, an
English
English usually refers to:
* English language
* English people
English may also refer to:
Peoples, culture, and language
* ''English'', an adjective for something of, from, or related to England
** English national ...
amateur
naturalist.
Description
Bullock's orioles are
sexually dimorphic
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
, with males being more brightly colored than females. In addition, adult males tend to be slightly larger and heavier than females.
Measurements:
* Length: 6.7-7.5 in (17-19 cm)
* Weight: 1.0-1.5 oz (29-43 g)
* Wingspan: 12.2 in (31 cm)
Adults have a pointed bill with a straight
culmen. In adult males, the tail is long, square, and jet black. All exposed skin is black, as are the claws and bill, though the base of the lower
mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
lightens to bluish-gray.
Adult males are characterized by strongly contrasting orange and black plumage, a black throat patch, and a white wing bar. The underparts, breast, and face are orange or yellow; by contrast, the back, wings, and tail are black. A black line extends from each eye to the black crown. The wing coverts (feathers not directly used in flight) are fringed white, forming a wing patch. Although the tail is mostly black, the outermost three or four rectrices (
flight feathers
Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tai ...
) are tipped orange, forming a T shape. Adult females, by contrast, have gray-brown upperparts, duller yellow on the breast and underparts, and an olive crown. Some females may also have a dark throat patch, similar to (but less extensive than) the one found in adult males; in all cases, females lack the black eye-line present in adult males. Females with throat patches are thought to be older individuals.
Following the general pattern observed among
icterids, the overall plumage pattern seen in immature male Bullock's orioles closely resembles that seen in adult females. Juveniles resemble adult females, but have darker wings, fresh wing coverts, and a pink or whitish bill. Sexual dimorphism is not obvious in juveniles.
Reproduction
Bullock's orioles are seasonally monogamous. The breeding season typically lasts from May until July. The exact timing of the beginning of the breeding season tends to vary geographically; in general, breeding begins later in the northernmost and westernmost portions of its geographic range. Mated pairs of Bullock's orioles cooperate to weave deep, pendant baskets in which are deposited between three and six eggs, though females tend to do much of the work. The nest is woven of plant fibers, primarily bark and fine grass fiber, though animal hair is also commonly used. The nest is lined with down, hair, and moss.
Both males and females rear the young and defend the nest from predators and nest parasites.
Bullock's orioles and Baltimore orioles typically hybridize in the Midwest where their geographic ranges overlap.
Communication
Both males and females sing. While males have a sweeter voice, females tend to be more prolific singers. This bird's song is similar to that of the Baltimore oriole, but faster and somewhat more harsh.
Distribution
Bullock's orioles are native to western North America, though they are sometimes found as vagrants in the eastern half of the continent.
[ During the breeding season, they are found as far west as the eastern foothills of the ]Cascade Range
The Cascade Range or Cascades is a major mountain range of western North America, extending from southern British Columbia through Washington and Oregon to Northern California. It includes both non-volcanic mountains, such as the North Cascades, ...
. Their breeding range stretches east to the Dakotas
The Dakotas is a collective term for the U.S. states of North Dakota and South Dakota. It has been used historically to describe the Dakota Territory, and is still used for the collective heritage, culture, geography, fauna, sociology, econo ...
, Kansas
Kansas () is a U.S. state, state in the Midwestern United States, Midwestern United States. Its Capital city, capital is Topeka, Kansas, Topeka, and its largest city is Wichita, Kansas, Wichita. Kansas is a landlocked state bordered by Nebras ...
, and northern Central Texas
Central Texas is a region in the U.S. state of Texas surrounding Austin and roughly bordered by San Saba to Bryan and San Marcos to Hillsboro. Central Texas overlaps with and includes part of the Texas Hill Country and corresponds to a ...
.[ This species can be found as far north as ]British Columbia
British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, for ...
in Canada and as far south as Sonora
Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. The state is divided into 72 municipalities; the ...
or Durango
Durango (), officially named Estado Libre y Soberano de Durango ( en, Free and Sovereign State of Durango; Tepehuán: ''Korian''; Nahuatl: ''Tepēhuahcān''), is one of the 31 states which make up the 32 Federal Entities of Mexico, situated in ...
in Mexico
Mexico (Spanish language, Spanish: México), officially the United Mexican States, is a List of sovereign states, country in the southern portion of North America. It is borders of Mexico, bordered to the north by the United States; to the so ...
.[ It is common throughout its range, but is absent in parts of ]Arizona
Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...
and Idaho
Idaho ( ) is a U.S. state, state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Monta ...
, where a combination of extreme elevation and an arid climate make for poor living conditions.[ During winter, this species retreats to Mexico and northern ]Central America
Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
. Its winter range extends south and east from Sinaloa
Sinaloa (), officially the Estado Libre y Soberano de Sinaloa ( en, Free and Sovereign State of Sinaloa), is one of the 31 states which, along with Mexico City, comprise the Federal Entities of Mexico. It is divided into 18 municipalities and ...
to Oaxaca
Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the Federative Entities of Mexico. It is divided into 570 municipaliti ...
.[
]
Behavior
Habitat
Like other members of the Icteridae
Icterids () or New World blackbirds make up a family, the Icteridae (), of small to medium-sized, often colorful, New World passerine birds. Most species have black as a predominant plumage color, often enlivened by yellow, orange, or red. Th ...
, Bullock's orioles prefer habitat edges. They especially prefer riparian
A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks a ...
corridors, open deciduous woodland, and scrub forest
Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity. It ma ...
.[ Observations during the breeding season indicate that members of this species prefer areas with an abundance of cottonwood, pecan, and (if near water) willow.][ In dry areas, this species prefers ]salt cedar
The genus ''Tamarix'' (tamarisk, salt cedar, taray) is composed of about 50–60 species of flowering plants in the family Tamaricaceae, native to drier areas of Eurasia and Africa. The generic name originated in Latin and may refer to the Tam ...
and mesquite.[ In California, eucalyptus trees are used as major sources of nectar.][
]
Diet
These birds forage in trees and shrubs, also making short flights to catch insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pa ...
s. They mainly eat insects, berries
A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, ras ...
, and nectar
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualist ...
. Other fruits eaten include oranges and sometimes grapes. In some locations, they may be seen using hummingbird feeders.
These birds readily come to a dish filled with grape jelly. Their parents lead the fledglings, feed them jelly, and then the adult males leave the area. The young stay at the jelly dish from first feeding in early July and leave late September.
Related species
For a time Bullock's orioles were considered conspecific with Baltimore orioles, but breeding data, later followed by data on molt timing and DNA, showed that Bullock's orioles are a distinct species.
References
External links
Bullock's oriole Species Account
- Cornell Lab of Ornithology
Bullock's oriole
Encyclopedia of Life
- USGS Patuxent Bird Identification InfoCenter
Bullock's oriole
BirdHouses101.com
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{{Taxonbar, from=Q851912
Bullock's oriole
Native birds of the Western United States
Native birds of the Plains-Midwest (United States)
Bullock's oriole
Bullock's oriole
Taxobox binomials not recognized by IUCN