Bullock's Oriole

The Bullock's oriole (Icterus bullockii) is a small, vibrant member of the New World blackbird family, Icteridae. Named in honor of the English amateur naturalist William Bullock, this species exhibits sexual dimorphism, with males donning a more striking orange and black plumage compared to the more subdued hues of the females. Adult males are slightly larger and heavier than their female counterparts.

Identification Tips

Adult males are resplendent with a black crown and eye-line, contrasting sharply with their orange face and underparts. Their wings are black with a distinctive white wing bar, and their long, square tails feature a characteristic "T" shape with orange-tipped outer feathers. Females, on the other hand, have gray-brown upperparts and a duller yellow breast, with some older individuals displaying a dark throat patch. Juveniles resemble females but have darker wings and a pink or whitish bill.

Habitat

Bullock's orioles are fond of habitat edges, particularly riparian corridors, open deciduous woodlands, and scrub forests. They show a preference for areas abundant with cottonwood, pecan, and willow trees, especially when near water sources.

Distribution

Native to western North America, Bullock's orioles breed as far west as the eastern foothills of the Cascade Range and as far east as the Dakotas and northern Central Texas. Their range extends north to British Columbia and south to Sonora or Durango in Mexico. During winter, they migrate to Mexico and northern Central America.

Behaviour

Bullock's orioles are seasonally monogamous, with a breeding season from May to July. They weave deep, pendant nests where they lay three to six eggs. Both parents participate in rearing the young and defending the nest. In the Midwest, where their range overlaps with the Baltimore oriole, hybridization occurs.

Song & Calls

Both sexes are vocal, with males producing a sweeter sound and females being more prolific singers. Their song is reminiscent of the Baltimore oriole's but is faster and more harsh.

Breeding

The nest, a collaborative effort between mated pairs, is a woven basket of plant fibers and animal hair, lined with down, hair, and moss. The breeding season's onset varies geographically, with later starts in the northern and western parts of their range.

Similar Species

Bullock's orioles were once considered conspecific with Baltimore orioles under the name northern oriole. However, breeding data, molt timing, and DNA analysis have since confirmed them as distinct species.

Diet and Feeding

These birds forage in trees and shrubs, catching insects in flight. They consume a diet of insects, berries, and nectar, and are known to visit hummingbird feeders. They also enjoy fruits such as oranges and grapes, and in some regions, they are particularly attracted to dishes of grape jelly.

Conservation status

The Bullock's oriole is currently listed as Least Concern on the IUCN Red List, indicating a stable population without significant immediate threats to its survival.