Baltimore Oriole (Icterus galbula)

Baltimore Oriole

[order] PASSERIFORMES | [family] Icteridae | [latin] Icterus galbula | [UK] Baltimore Oriole | [FR] Oriole orange | [DE] Baltimoretrupial | [ES] Bolsero de Baltimore | [NL] Baltimore-troepiaal

Subspecies

Monotypic species

Physical charateristics

Approaches size of Starling with rather similar bill and head shape but much longer body and rather long, slightly rounded tail. Colourful, arboreal icterid, with long pointed bill. Yellow-orange below at all ages, but tone varies. Adult male striking: black hood, back, wings, and tail-centre, orange forewing, rump, underparts, and tail-edges, and white wing-bar. Female and immature duller, with double white wing-bar.

Listen to the sound of Baltimore Oriole

[audio:http://www.aviflevoland.nl/sounddb/B/Baltimore Oriole.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 28 cm wingspan max.: 32 cm
size min.: 17 cm size max.: 20 cm
incubation min.: 11 days incubation max.: 14 days
fledging min.: 9 days fledging max.: 14 days
broods: 1   eggs min.: 3  
      eggs max.: 6  

Range

North America : East

Habitat

Breeds in temperate Nearctic lowlands, favouring wooded river bottoms, upland forest, shelterbelts, and partially wooded residential areas and farmsteads. Absent from pure coniferous forest but after their clearance colonizes ensuing deciduous growth.

Reproduction

Males arrive on breeding grounds in the spring a few days before females. Courtship displays by the male consist of bowing, to show off the bright orange front and black back, and singing. The female builds a woven pouch nest hanging from the end branches of trees, well concealed by leaves. She builds a new nest each year with little or no help from the male. Icterus galbula prefers to build in elms, maples, willow, or apples, twenty-five to thirty feet above the ground. Any available plant and animal fibers may be used.
The female lays four to six eggs, typically four. The eggs are pale grayish or bluish white, irregularly blotched and streaked with browns and black. The female incubates for twelve to fourteen days. Both parents feed the nestlings. Fledglings will stay with their parents for two weeks, and are fed by their parents duing that period. Baltimore orioles lay only one brood per season

Feeding habits

Baltimore orioles eat primarily caterpillars, including many pest species. They also eat other insects, some small fruits, and nectar. They are an important predator of the nuisance forest tent caterpillar, Malacosoma disstria, which it eats in both its larval and pupal forms. Large larvae are seized and smashed against a twig to break them open and avoid the setae (stiff, hair-like structures). Pupae are pulled out of their cocoon.

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Breeds in south-east Canada and eastern USA, west to a line from central Alberta to north-east Texas, hybridizing with Bullock?s Oriole I. bullockii in south-east Alberta, North Dakota, eastern Colorado, western Nebraska, western Oklahoma, and north-central Texas. Accidental. Iceland, Britain, Netherlands, Norway.
Baltimore Oriole status Least Concern

Migration

Chiefly migratory, wintering mainly from Mexico to north-west South America (Colombia and Venezuela). Since c. 1950, numbers wintering in temperate North America (especially on Atlantic seaboard) have increased greatly, notably where artificial food available. Autumn migration on broad front, but chiefly west of Florida, Cuba, and Yucatan (Mexico). Spring route mostly reverse of autumn, but birds more common in Florida in spring.
Vagrants have reached south-east Alaska, Churchill (Manitoba, 59 degrees N), and south-west Greenland (65 degrees N), and many others wander shorter distances beyond breeding range. Rare vagrant to Atlantic seaboard of west Palearctic, mainly in autumn. Of 18 records in Britain up to 1995, 13 in September-October, 2 in May, and 1 in December; also long-staying winter individuals Dyfed (1989), Essex (1991-2).

Distribution map

Baltimore Oriole distribution range map

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