Based on 1,903 research-grade iNaturalist observations in Colorado, Bullock's Oriole is most often recorded in May; in Colorado it behaves like a seasonal. It ranks #52 among birds recorded in the state in our data.
Icterus bullockii
Bullock's Oriole in Colorado by month
Bars show research-grade observations per month. They mix true seasonality with how often people are outdoors, so treat small numbers with caution.
Also seen in Colorado in May
Red-winged Blackbird
Canada Goose

Mallard

American Robin
Black-billed Magpie

Spotted Towhee

Great Blue Heron

Western Tanager
Places to look in Colorado
White River National Forest
Denver Botanic Gardens
Rio Grande National Forest
National ForestSan Juan National Forest
Roxborough State Park
Mancos State Park
FAQ
When does Bullock's Oriole appear in Colorado?
Mainly May–July, with the most records in May.
How common is Bullock's Oriole in Colorado?
It ranks #52 by number of iNaturalist observations among birds in Colorado (1,903 records in our sample).