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Having spent time in Louisiana in rice fields doing research, I was quite familiar with the red-winged blackbird and the songs it sings. But one year I was doing a field study on Canada geese in Colorado when the peacefulness of the study site was shattered by the most raucous screech I’d ever heard. Turns out it was a yellow-headed blackbird which I had never seen up until this point. Now I see them breeding out at Jim Hamm on a regular basis.
Yellow-headed blackbirds were first described by the nephew of Napolean Bonaparte in 1825. The male yellow-headed blackbird has, as its name implies, a bright yellow head and chest with a black body. In fact, the scientific name for this species, Xanthocephalus, means “yellow-headed.” There is a large white patch along the wing where it bends which looks more like a stripe and is barely visible when the bird is at rest. On the wing, the white patches are prominent. Females and immature yellow-headed blackbirds are brown in color and any yellow on the head is much more subdued than in the males. Females don’t have the white on the wings.
In contrast to the yellow-headed blackbirds, red-winged blackbirds (or tricolored blackbirds as they are also called) are smaller in size. They are all black with the exception of red and yellow shoulder patches, also known as epaulets. Females are dark brown with prominent streaking and may have a white eyebrow.
Breeding occurs in wetlands, although the red-winged blackbird may also sometimes breed in meadows and undisturbed fields. The yellow-headed blackbird and red-winged blackbird will nest in the same marshes, but the yellow-headed blackbird will occupy the most preferred nesting spots because it is larger. Nesting often occurs in cattails, bulrushes, or reeds.
Males of both species will sing and display to attract females. Male yellow-headed blackbirds will chase potential female mates, grabbing the female’s rump with their bills. At this point, the pair will fall into vegetation where the male lets go of the female. Red-winged blackbirds have a similar display. Male red-wings will also sit high on marsh vegetation singing repeatedly and spreading their wings to show off their shoulder patches. Many times, they will also lower and spread their tail as well. Similarly, male yellow-headed blackbirds will sit on high perches such as bare tree branches that overhang the marsh, and point their beak to the sky while calling and spreading their tail feathers.
Yellow-headed blackbirds may have up to eight females on their territories while red-winged blackbirds may have up to 15. However, anywhere from one quarter to one half of nestlings were fathered by a male other than the male where the nest is located. This is true for both species.
The female yellow-headed blackbird will choose a nesting site that overhangs the water. Yes, sometimes nestlings fall out and have to swim to vegetation! The female begins building a nest of wet vegetation that she weaves around several cattails or other stems. Eventually, the nest will have an inner and outer wall all made of the same vegetation. The inside of the nest is about three inches wide and two and a half inches deep whereas the outside of the nest is five to six inches across. It is typically just as tall as it is wide. Each nest consists of 2-5 eggs (also called a clutch). Eggs take 12-13 days to hatch and the young leave the nest (fledge) around two weeks of age. Only one brood of young is raised per year. Males will help feed the young, but usually only do so for the first nest established on their territory, ignoring the other nestlings.
Female red-winged blackbirds choose nesting sites with some input from the territorial male. Nests are built very near the water’s surface in dense vegetation, such as cattails or bulrushes. Nest building occurs very similarly to the yellow-headed blackbird in that marsh vegetation is woven around several stems. First, the female makes a platform of the woven vegetation. Then she adds wet leaves and decaying material, and finally builds a cup that is plastered with mud. Fine, dry grasses are used to line the cup of the nest. In the 1930’s, a naturalist picked apart a red-winged blackbird nest to examine it and found cattail leaves up to two feet in length! The finished nest is 4-7 inches across and 3-7 inches deep. Each clutch has 2-5 eggs with incubation lasting 11-13 days. Nestlings leave the nest around two weeks of age.
Catching a glimpse of these birds can range from easy to difficult, but as with all birdwatching, patience is rewarded. As I mentioned, Jim Hamm seems to be a good place to see both species as there is a cattail marsh along the edges of the pond. Yellow-headed blackbirds are more common here, so you may have more trouble finding the red-winged blackbird. However, the cattail marsh at the Longmont Recreational Center is host to numerous red-winged blackbirds.
The best times to spot these birds is early morning or late afternoon. Males will be much easier to spot than the females. Often, you will hear the birds before seeing them. Red-winged blackbirds make a conk-a-ree sound which is perhaps the most distinctive sound made by these birds. They do have other calls as well, but locating this particular sound is likely to lead you to sighting a male of the species. Female red-wings tend to stay close to the ground and are therefore harder to spot. Male yellow-headed blackbirds make a screeching sound, often likened to the sound of a door swinging on rusty hinges. Females of this species also tend to stay low in the marsh. Next time you are out near a cattail marsh, look for these beautiful birds.
The Longmont Weekly Wild is a weekly column about all things wildlife and wild in Longmont. You can find previous articles under the Lifestyle section.