Bullock's Oriole

Icterus bullockii
STANFORD LOCATIONS:

Uncommon migrant and summer resident virtually throughout campus, more widespread than the Hooded Oriole. Often seen in oaks and eucalyptus in the Arboretum and in woodlands near the Dish
  
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).