The Tricolored Blackbird (Agelaius tricolor) is a medium-sized icterid found in marshes and agricultural lands from southwestern Oregon to northwestern Baja California. Males are black with dark red shoulder patches and white wing coverts, while females are gray with lighter throats. They are the most colonial passerines in North America, forming massive breeding colonies and exhibiting itinerant breeding in both spring and fall. The species is currently listed as Endangered on the IUCN Red List.
Learn to identify
Adult male Tricolored Blackbird in California.
Learning lesson · openly licensed photographs, labelled by BirdBot; labels checked against the cited sources and approved by AI
Slender conical bill: a typical blackbird bill. Deep red shoulder patch: darker red than a Red-winged Blackbird's. White band below the red: white to cream, not yellow. Entirely black body: females are streaked gray-brown. On a red-shouldered blackbird, check the band: white, not yellow.
Faded Red-winged males can show a whitish border in late summer.
Sources: Audubon Guide to North American Birds: Tricolored Blackbird · All About Birds (Cornell Lab): Tricolored Blackbird Identification · Wikipedia: Tricolored blackbird (revision 1340775629)
Photo: Laura Gaudette, CC BY 4.0, via Wikimedia Commons; labels added by BirdBot.
Tricolored Blackbirds exhibit clear sexual dimorphism, making sex identification straightforward in the field. Males are larger than females and display a glossy black body with distinct dark red shoulder patches (epaulets) bordered by white median wing coverts. This tri-color pattern gives the species its common name. In the fall, male plumage may appear browner. Females are shades of gray with a lighter gray throat. They lack the red and white wing patches of males.
A critical field challenge is distinguishing female Tricolored Blackbirds from female Red-winged Blackbirds (Agelaius phoeniceus). Tricolored females are generally darker, possess more pointed wingtips, and have more slender bills compared to their red-winged counterparts. Tricolored Blackbirds measure approximately 22 cm in length with a wingspan of about 35.5 cm and weigh roughly 59.5 grams.
Tricolored Blackbirds are habitat specialists that require areas near water. Their primary habitats include marshes, wetlands, and grasslands. They depend on aquatic vegetation as a substrate for building nests and utilize adjacent grasslands or agricultural pastures, such as rice, grain, or alfalfa fields, for foraging. Their range extends from the marshes and farmlands of southwestern Oregon to northwestern Baja California.
These birds are the most colonial species among North American passerines. Outside the breeding season, they gather in large flocks and migrate seasonally between different areas. During the breeding season, males display strong territoriality, defending small territories that contain several nests. The Animal Diversity Web account estimates these territories at about 10.7 square meters, a specific historical metric from that source. Foraging typically occurs far from the colony, with males ranging up to 6.5 km to acquire food for their nestlings.
Tricolored Blackbirds are itinerant breeders, meaning they breed twice a year in two separate locations. Spring breeding occurs from mid-March through late April, while a second breeding season takes place in the fall. Colonies can be immense, with reports of up to 200,000 nests in a single site. The species exhibits polygyny, where one male may breed with one to four females.
Females build the nests and lay eggs, typically producing clutches of one to four eggs, with three being the most common. Incubation lasts between 11 and 14 days, with females remaining at the nest during the daytime. Males care for the young after hatching. Chicks fledge approximately nine days after birth and require an additional 15 days to become independent. Males begin breeding at two years of age, while females can breed at one year.
Tricolored Blackbirds are omnivorous, feeding on both animal and plant matter. Their diet varies by region and crop availability. Insect prey includes grasshoppers, beetles, moths, and fly larvae. They also consume grains, seeds, rice, and other crops. Nestlings are fed primarily insects, highlighting the importance of insect abundance in their breeding habitats.
The vocalizations of the Tricolored Blackbird are distinct from those of the Red-winged Blackbird. They produce a nasal “oo-grreee” call that begins loud and gradually softens. They also emit a “drdodrp” call. Both calls have a lower pitch than the typical song of the Red-winged Blackbird. Females tend to be silent during incubation.
The Tricolored Blackbird is listed as Endangered (EN) on the IUCN Red List, as recorded in AviList v2026. This status reflects significant population pressures. The species is federally protected under the Migratory Bird Treaty Act of 1918 and is listed as a Species of Special Concern by the California Department of Fish and Game. Population declines are attributed to the loss of wetland habitat, urban sprawl, and agricultural changes that reduce foraging and breeding areas. Conservation efforts focus on habitat development on public lands, colony preservation, and educating landowners on coexisting with the species.
Because Tricolored Blackbirds are colonial and often found in sensitive wetland or agricultural habitats, ethical observation is crucial. Avoid disturbing active nesting colonies, especially during the spring and fall breeding seasons. Observe large flocks from a distance using binoculars or a spotting scope. Listen for the nasal “oo-grreee” call to confirm identification without needing a close visual. A useful field exercise is to locate a marsh edge or agricultural field boundary and scan for the dark red shoulder patches of males against the vegetation, noting the lower-pitched calls compared to nearby Red-winged Blackbirds.
