Northern Oriole

Icterus bullockii Swainson
STANFORD LOCATIONS:

  
Nest
Location
Nest
Type
Eggs
Mating System
Dev.
Parental Care
Primary &
2ndary Diet
Foraging
Strategy
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F
I: 12-14 DAYS
ALTRICIAL
15 feet - 30 feet
(6 feet - 60 feet)
F -M
4-5
(3-6)
MONOG?
F: 12-14 DAYS
MF
FRUIT
NECTAR
HAWKS
BREEDING: Open and riparian woodland, decid forest edge, open areas with scattered trees, around human habitation. 1 brood.
DISPLAYS: Courting male rises to full height, bows low to female with tail spread and wings slightly raised; alternates between these two postures.
NEST: Rarely in conif tree, attached at rim or secured at sides to drooping branch; woven of plant fiber strips, lined with fine grass, plant down, hair. Built in 4.5-15 days.
EGGS: Pale grayish- to bluish-white, marked with dark colors. 0.9" (23 mm).
DIET: Includes few spiders, snails; some buds in spring.
CONSERVATION: Winters from c Mexico s to n e S.A., Greater Antilles; increasingly remains in e U.S. and CA due to feeders. Uncommon cowbird host; may elect cowbird eggs.
NOTES: Formerly called Northern Oriole, now considered as two species, Baltimore and Bullock's Orioles. Loosely colonial in riparian woodland as a consequence of nest site scarcity. Female (Bullock's) sings early in nesting season. Males sexually mature at 1 year but acquire adult plumage in year 2. Postbreeding flocks of juveniles and females; adult males solitary. Solitary to slightly gregarious in winter in groups of up to 4.
ESSAYS: Great Plains Hybrids; Decline of Eastern Songbirds; Feeding Birds; Taxonomy and Nomenclature.
REFERENCES: Flood, 1984; Pleasants, 1979; Sealy, 1980.

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Except for Stanford Locations, the material in this species treatment is taken, with permission, from The Birder's Handbook (Paul Ehrlich, David Dobkin, & Darryl Wheye, Simon & Schuster, NY. 1988).