- 8.3–10.2 in
- 16.5–17.3 in
- 1.6–3.5 oz
- Smaller than a Common Grackle; larger than a Red-winged Blackbird.
- Carouges à tête jaune (French)
- Tordo cabeciamarillo (Spanish)
- In 1825 Charles Lucien Bonaparte, nephew of Napoleon Bonaparte, gave the first detailed description of the Yellow-headed Blackbird, which was collected in 1820 by Thomas Say and Sir John Richardson.
- The Yellow-headed Blackbird often nests in the same marsh as the Red-winged Blackbird. The larger Yellow-headed Blackbird is dominant to the Red-winged Blackbird, and displaces the smaller blackbird from the prime nesting spots. The Yellow-headed Blackbird is strongly aggressive toward Marsh Wrens too, probably because of the egg-destroying habits of the wrens. When the Yellow-headed Blackbird finishes breeding and leaves the marsh, Marsh Wrens expand into former blackbird territories.
- The male Yellow-headed Blackbird defends a small territory of prime nesting reeds. He may attract up to eight females to nest within his area. The male helps feed nestlings, but usually only in the first nest established in his territory. The other females have to feed their young all by themselves.
- Because Yellow-headed Blackbirds always build their nests over the water, nestlings sometimes fall in and have to swim short distances to vegetation.
- Pleistocene fossils of Yellow-headed Blackbirds (from 100,000 years ago) have been dug up in California, New Mexico, and Utah.
- The Yellow-headed Blackbird’s scientific name, Xanthocephalus, means “yellow head.”
- The oldest Yellow-headed Blackbird on record was at least 11 years, 8 months old. It had been banded in Saskatchewan and was found in Nebraska.
Yellow-headed Blackbirds breed in wetlands in prairies, mountain meadows, quaking aspen parklands, and shallow areas of marshes, ponds, and rivers. They nest in cattails, bulrushes, or reeds, often alongside nesting Red-winged Blackbirds. To forage, they may move to surrounding grasslands, croplands, or savanna. In winter, Yellow-headed Blackbirds join up by the thousands into large flocks and forage in crop fields, ranchlands, and farmyards from Arizona, New Mexico, and Texas through much of Mexico. The northernmost wintering populations are mostly males, while the southern ones are mostly females.
Yellow-headed Blackbirds eat mostly insects in summer and seeds the rest of the year. They catch aquatic insects at the water’s surface, including beetles, grasshoppers, dragonflies, caterpillars, flies, ants, and spiders. Outside of the breeding season they forage in uplands, eating grains and weed seeds. They form “rolling” flocks in farm fields, with individuals continually taking flight at the rear of the flock and landing at the front lines to feed. After establishing a foraging site, a flock will return to the same area repeatedly for several days. The blackbirds probe into soft ground and spread their bills to open up leaf sheaths or enlarge holes. They also flip over stones to unearth food.
- Clutch Size
- 2–5 eggs
- Number of Broods
- 1 broods
- Egg Length
- 0.9–1.1 in
- Egg Width
- 0.7–0.7 in
- Incubation Period
- 12–13 days
- Nestling Period
- 7–14 days
- Egg Description
- Grayish to greenish white, splotched with brown, rufous, and pearl gray.
- Condition at Hatching
- Helpless, with eyes closed. Nestlings have pink skin covered with patches of tawny down, and their mouths are bright red and pink.
The female builds the nest by herself. She weaves long strands of wet vegetation, collected from the surface of the water, around 4–5 upright stems. She adds more strands and more supports, and then an outer wall and an inner cup of the same materials. The outside of the nest is 5–6 inches across and about the same height, while the inside measures about 3 inches across and 2.5 inches deep.
The female chooses a nest site within a male’s territory, always picking a spot that overhangs the water. She affixes the nest to live or dead vegetation—usually cattails, bulrushes, or reeds, but sometimes willows, tamarisk, or wild rice.
Males establish territories in deeper-water areas of marshes, often among cattails and bulrushes. Each breeding male attracts a harem of up to eight females that nest within his territory, which he defends from other males. This arrangement means that some males don’t have any mates at all, particularly younger ones. Second-year males usually don’t even secure a territory for themselves, and become “floaters” with no fixed place in the marsh. In some cases breeding birds forage only within their territory, but in other instances breeding is loosely colonial, with birds finding food outside of their own territories. Females defend a small area around the nest and frequently mate with males from neighboring territories when their own mate is absent. Yellow-headed Blackbirds seem to preferentially nest and forage near Forster’s Terns when possible, cooperating with the terns to mob predators or give alarm calls. Yellow-headed Blackbirds displace smaller Red-winged Blackbirds and Marsh Wrens from prime nesting spots in a marsh. Their nest predators include gulls, magpies, Common Grackles, American Bitterns, American Coot, Marsh Wrens, rails, bull snakes, garter snakes, blue racers, mink, red foxes, raccoons, deer mice, and striped skunks.
Yellow-headed Blackbirds are numerous and their populations are relatively stable in the long term, though they fluctuate considerably from year to year depending on wetland conditions, rainfall, and droughts. The North American Breeding Bird Survey found that this species may have experienced a small decline between 1966 and 2014. Partners in Flight estimates a global breeding population of 11 million with 85% spending some part of the year in the U.S., 75% in Mexico, and 15% breeding in Canada. This U.S.-Canada Stewardship species rates a 9 out of 20 on the Continental Concern Score and is not on the 2014 State of the Birds Watch List.. Yellow-headed Blackbirds appear to be in no danger as long as their habitat remains intact. But because they breed only in wetlands, drainage projects can be a threat (though it tends to affect shallower wetlands more than the deeper-water, bigger wetlands where these blackbirds tend to nest). On the other hand, new fields of corn, sunflower, and small grains have created a vast food supply for the birds outside of the breeding season, probably increasingly the survival rate of fledged young. Because of their diet and habitat choice, Yellow-headed Blackbirds can suffer from exposure to herbicides and pesticides, such as when herbicides are used to reduce wetland vegetation, when the birds eat insects or grain treated or cropdusted with pesticides, or when farmers use toxic baits or sprays directly against the Yellow-headed Blackbirds themselves. Measures taken to protect crops also include trapping, netting, shooting, and hazing the birds with aircraft.
Medium-distance migrant. In the fall, populations that breed in the Canadian prairies migrate southeast and then due south across the United States to wintering grounds in the Southwest and throughout Mexico. Males tend to winter farther north, while more females migrate all the way to the species’ southern limits. Yellow-headed Blackbirds migrate during the day in long and irregular flocks, gathering for the night at wetlands and roosting with other blackbird species.
Yellow-headed Blackbirds may visit feeders to eat seeds and grains, including sunflower seeds.
Find This Bird
In the Midwest and West, look for Yellow-headed Blackbirds both in freshwater wetlands and in nearby farm fields. Though they are striking in appearance, these birds spend a substantial time perched out of view in cattails or reeds, so listen for their harsh check calls and bizarre grinding, buzzing songs in order to pinpoint their location. When searching in farm fields, look for large concentrations of blackbirds and then scan them carefully. If the bulk of the birds are Red-winged Blackbirds or some other species, don’t despair—focus on finding a white wing patch or yellow head among the other species.