Bullock's Oriole, Icterus bullockii


Bullock's Oriole
The beautiful adult male orioles returning from the tropics to breed over much of North America are one of the pleasures of spring. The Bullock's Orioles are found in the west, their close relatives the Baltimore Orioles in the east; the two were once considered different forms of a single species. The males are clearly distinguished by the orange and black striped head of the Bullock's vs. the all-black head of the Baltimore. The females and juveniles can be more difficult to distinguish.

Bullock's Orioles
Above, a courting pair of Bullock's, shortly after their arrival in late March. Below, another adult female, in late April in Arizona. 


Bullock's Oriole
Adult female and juvenile Bullock's Orioles are similar. Adult females tend to have white wing bars, above, where juveniles have buff ones, below; adult feathers are more worn, being a year old because the species only undergoes a single (fall) molt; and finally adult females tend to have more extensive and brighter yellow on the underparts than juveniles. Note also the visible gape on the juvenile below.

Bullock's Oriole


Bullock's Orioles
An adult female feeding a fledgling near the nest in June.


Bullock's Oriole
I saw this bird singing, and thought it might be a year-old male, which do breed. However
it does not have the black stripe through the middle of the chin of the yearling male,
see below, and Birds of North America Online reports of this species that "Early in nesting
period and before and during nest-building, females sing regularly, and may sing more than
males." 

Bullock's Oriole
Year-old males have a black stripe throught the yellow throat, and so do many adult females; if the black throat stripe is accompanied by black lores, as here, the bird is more likely an immature male than a female. Also, this bird was keeping company with an adult pair; most year-old males form pairs and breed, but some accompany an adult pair as a helper.

Bullock's Oriole
In conclusion, one more beautiful adult male Bullock's Oriole! This one has an insect, which it may have been carrying to the nest as food for nestlings. Orioles eat insects throughout the year, but also consume nectar; a standard way to attract them is with a half of an orange.