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By Althea Dotzour
Geographic Range
During the summer, the yellow-headed blackbird migrates north to the west-central portions of Canada and the United States. Its range extends as far west as central-interior British Columbia, moving directly south through the central-interior west coast to northeastern Baja California. The eastern edge of the Yellow-headed Blackbird's range extends from western Ontario to northern Missouri.
During the winter, it can be found from California to Texas as well as in Mexico and casually in Costa Rica. (Ditital Atlas of Idaho version 1.3, 2000; Stokes and Stokes, 1996)
Biogeographic Regions:
nearctic 
(native ); neotropical (native ).
Habitat
Yellow-headed blackbirds are found in freshwater marshes during the summer. They particularly like to live amongst cattails, tule, and bulrush. During migration and over the winter months, the Yellow-headed Blackbird is found in open, cultivated lands, in fields, and in pastures. (Ditital Atlas of Idaho version 1.3, 2000)
Terrestrial Biomes:
savanna or grassland ; forest .
Aquatic Biomes:
lakes and ponds; rivers and streams.
Physical Description
(2.29 oz)
His bright yellow hood and black body best identify the male Yellow-headed Blackbird. A white patch on his wing can be seen both while perched or flying. The female's coloring is more subdued. She can be best identified by her duller-yellow supercilium, throat, and breast. The rest of her body is grayish-brown, and she has white streaks extending down her breast. Juveniles are similar in appearance to the females.
Both male and female Yellow-headed Blackbirds are 9.5 inches (24 cm) long and have sharply pointed black bills. (Gough et al. 1988; Stokes and Stokes 1996)
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
A polygynous breeder, the male Yellow-headed Blackbird stakes out his claim in a habitat of reeds over permanent open water. Females arrive to the area a few days later and are pursued by the males who sit on elevated vegetation with a spread tail and half-open wings and "sing." Sadly for human listeners, his song is composed of short, choked notes that sound more like a saw grating metal than a Romeo in love. The male Yellow-headed Blackbird may be able to secure up to as many as six mates depending on the quality of his territory. Male Yellow-headed Blackbirds who acquire new territory do not destroy broods sired by the previous territorial male. This tolerance for unrelated young may help them attract new mates as the females may mate and lay a second clutch with the new male.
The female builds a bulky, woven nest of wet vegetation in the reeds over water. As the nest materials dry, it shrinks, tightening its support on the emergent vegetation upon which it is attached. Nest building takes two to four days, and the nest is suspended ½ foot to three feet above the water.
The female Yellow-headed blackbird lays 3-5 greenish-white eggs with dark marks. Incubation lasts 11-13 days, and the chicks are altricial. They fledge within 9-12 days of hatching, and during their time in the nest, both parents feed them. For the first four days after birth, the chicks are fed at least partly by regurgitation. The amount of begging for food by Yellow-headed Blackbird chicks is related to the amount of food the parents bring to the nest. As nestlings, male Yellow-headed Blackbirds are significantly larger than their female counterparts. Yellow-headed Blackbirds only raise one (possibly two) broods each summer while their neighbors, the Red-winged Blackbirds, raises two to three broods (Elrich et al. 1988; Ortega and Cruz 1992; Gori et al. 1996; Stokes and Stokes 1996; Price 1998)
Key reproductive features:
iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous .
Behavior
Yellow-headed Blackbirds feed by gleaning insects and seeds from plants and from the ground, and by hawking insects in the air. Their main method of foraging is to push their bill into the ground or a food item and then force their bill, as well as the substrate, open.
Yellow-headed Blackbirds are strongly territorial during the breeding season. They prefer nesting in marshes above water two to four feet deep. Their nests are usually clumped in a different part of the marsh from the Red-Winged Blackbird who prefer nesting over shallower water. Marsh Wrens (Cistothorus palustris) occasionally destroy Yellow-headed Blackbird nests, so the territorial male excludes Marsh Wrens from their nesting areas.
During fall migration, males often form flocks that are separate from the females and young. Over the winter, the Yellow-headed Blackbird forms enormous flocks with other species of birds. (Elrich et al. 1988; University of Guelph. 1998)
Key behaviors:
flies; motile .
Food Habits
Insects are the favorite food of the Yellow-headed Blackbird. It also forages on the ground to eat seeds, spiders, grass, and forb seeds. This blackbird can be seen foraging in fields, meadows, ranches, agricultural areas, and farms. (Ehrich, Dobkin, and Wheye, 1988; Stokes and Stokes, 1996)
Primary Diet:
omnivore .
Animal Foods:
insects.
Plant Foods:
seeds, grains, and nuts.
Economic Importance for Humans: Negative
In the spring, several species of blackbirds including the Yellow-headed Blackbird feed on newly planted seed in agricultural fields. They are therefore somewhat responsible for losses farmers absorb in missing crops. (Atkinson 1969)
Economic Importance for Humans: Positive
As an insect eater, the Yellow-headed Blackbird may benefit humans by eating potentially harmful (or painful) insects such as crop-eating grasshoppers.
Conservation Status
IUCN Red List: [link]:
Least Concern.
US Migratory Bird Act: [link]:
Protected.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
State of Michigan List: [link]:
Special Concern.
Yellow-headed Blackbirds are widespread, abundant, and secure. The Eastern and Central Breeding Bird Surveys have shown increases in Yellow-headed Blackbird populations of around 2% per year from 1966-1993 while the Christmas Bird Counts have recorded decreases in populations of more than 2% per year. (Stokes and Stokes 1996; Digital Atlas of Idaho 2000). This is a species of special concern in Michigan.
Contributors
Althea Dotzour (author), University of Michigan.
Terry Root (editor), University of Michigan. Stephanie Seto (editor), University of Michigan.
