Red-winged blackbirds

Red-wings are found all over North America, barring the very far north and some patches of unlivable habitat. They are here in Juneau, too; two easy places to see them are Kingfisher Pond in the Lemon Creek area and the Duck Creek Greenway near Nancy Street in the Valley. I’ve had fun this spring, hanging out near these little wetlands and watching their behavior. And they used to nest in the wet meadow area between Sunny Point and Fred’s, but I haven’t seen them there for years.

My ties to Red-wings go back decades, to the beginning of my career, which began in the marshes of eastern Washington, where I studied yellow-headed blackbirds that nested in the same marshes as red-wings. The two species are interspecifically territorial, defending territory borders against each other as well as against members of their own species. Both species are often polygynous; a male’s territory commonly included the sub-territories of several females.

Red-wing males are fiercely territorial, defending their space by singing and displaying their showy red epaulets, flying from perch to perch to cover all their borders. A really intense confrontation between two males involves perching next to each other, standing upright and very sleek, pointing their bills to the skies. Males after their first winter are often called first-year males; their plumage is not fully black but some of the back and chest feathers have brownish edges. In addition, their epaulets are not as intensively red as those of full adults. First-year males are capable of breeding and sometimes invade the territories of adults or attempt to set up territories of their own but they are usually subordinate to full adults. They mature fully by the second year and then can hold their own quite well. Incidentally, those ‘epaulets’ appear to be on the shoulder (hence the name)when the wing is folded, but they are not close to the shoulder joint–they are really closer to the wrist joint.

Females hold sub-territories within a male’s territory and defend their borders against other females. They choose where to settle using many kinds of clues, including especially habitat quality, but also characteristics of the males, and perhaps an assessment of space-available on a male’s territory. In some cases, a preference for unmated males occurs, but it is commonlyovercome by the other considerations. Although it is common for a male’s harem to have three or four females, the record number seems to be fifteen females on the territory of one male.As is true for many other songbirds, it is not uncommon for a nest to harbor chicks with two or even more fathers, the result of so-called extra-pair sexual activity.

Females build the nest, usually suspended from wetland vegetation, and do the incubating of eggs. Males help feed their chicks in some populations but not in others. So far, I haven’t seen the males at Kingfisher Pond attend to active nests at all.

Blackbird female and chick. Photo by Bob Armstrong

Red-wings generally prefer to nest in wetlands, although they sometimes use agricultural fields and other upland habitats.They eat various insects and even seeds in the breeding season. Their favorite foods include dragonflies and damselflies, which are particularly vulnerable to capture at a time of transition between aquatic living of larvae (called naiads) and aerial living of the adults. The aquatic naiads crawl up on the wetland vegetation, split open the exoskeleton, and emerge as adults; this usually takes several hours, at least. Furthermore, initially those new adults (called tenerals) are soft-bodied and their wings need some time to expand and harden so the adult can fly. And that’s when the blackbirds can nab them easily. 

Red-wings are feisty birds, ready to defend their holdings against intruders and potential predators. This they do by screaming, making diving attacks, chasing, and even physically attacking. They chase crows and ravens, hawks and even eagles (https://vimeo.com/564686399.

A blackbird chasing a northern harrier. Photo by Kerry Howard

One drizzly day, I wore a black rain jacket when I went to see what was happening at Kingfisher Pond. The male redwing whose territory includes the platform and adjacent sedges went crazy. He made the ‘check’ notes of annoyance and the whistle-like call of alarm for many minutes and swooped low just over my head several times. He’d never done this on earlier visits (sans black jacket), so I conclude, provisionally, that he really did NOT like my black jacket. Perhaps I reminded him of crows and ravens, potential predators who would be chased if they got that close.

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Colors in confrontation

I once worked in an office in which a co-worker announced that the color red was aggressive, so red clothing should be disallowed in the workplace—or anywhere else!

Well! I’d always found red to be a rather cheerful hue, the color of ripe cherries and raspberries, of wild columbines and scarlet monkeyflowers, of holly berries and Santa Claus. There are some un-cheerful associations with that color, too, such as blood, but to ban a color entirely seemed excessive, to put it mildly. Perhaps you can guess what color my shirt was, the next day!

In the bird world, color is used as part of the process of attracting mates, as we have seen. Color (not just red) is also used to signal social status and levels of aggressiveness.

For example, black-capped chickadees, close relatives of our chestnut-backed chickadees, vary in the darkness of their black cap, and dark-capped individuals enjoy higher social status. Their greater dominance allows them better access to food in winter. House sparrows (those European introductions that can be seen in cities and farms all over the Lower Forty-eight) with high levels of testosterone develop large black patches on the chest. Big patches show other birds that these individuals would win a confrontation. And Harris’ sparrow males that have a high rank in the dominance hierarchy also have large black chest patches. The big black badges signal ‘don’t mess with me!’ There is an advantage both to the males with large patches and the subordinate males with small patches, because they can recognize each other’s status and avoid a direct fight.

White-throated sparrows breed across much of northern North America and occasionally wander into Southeast. Adults, both male and female, come in two color phases. One has black and white stripes on the crown of the head, and the other has brown and tan stripes there (as do juveniles). Detailed research has shown that the black-and-white-striped adults are more aggressive, spending much of their time chasing potential rivals. Although they often obtain and keep the best territories, they tend to neglect their parental duties. So if both members of a pair have black and white crowns, their nesting success tends to be low.

In contrast, a pair of brown-and-tan-crowned adults are less aggressive and markedly more attentive parents. They often lose battles with the black-and-whites and may be forced into suboptimal habitat, where even their better parenting cannot compensate entirely, so their nesting success also tends to be low. Thus, the most successful pairs of white-throated sparrows have one member of each kind: an aggressive black-and-white one and a parental brown-and-tan one.

Experiments with eastern bluebirds (whose appearance is much like the western one) have shown that males with brighter blue plumage out-compete the duller males in contests over nest boxes. So the brighter males get the best nest boxes, and get them earlier, which also gives them first choice of females. I’m tempted to speculate that, like bright mountain bluebirds, they also do well in obtaining extra-pair copulations.

Photo by Bob Armstrong

Red-winged blackbird males have red epaulets with a yellow border. In aggressive encounters with each other, they show off these bright red patches by flaring the wings and erecting the feathers. (You can sometimes see them in the marsh by the Pioneer’s Home or in the big marsh on Eagle River.) They can cover the epaulets with black feathers on the upper back when they want to sneak into a neighbor’s territory unaccosted by the owner. In this case, the optional display of color signals not social status but level of aggressiveness.

In an earlier essay, I noted that much of the variety of color and pattern that we see in the animal kingdom is the result of mate choices and competition to be attractive to the other gender. Another portion of the array of colors and patterns can now be seen to be a result of signaling social status and level of aggression.

I have not addressed the matter of color with respect to camouflage, or signaling age or gender or species, or mimicry, or warning colors, and so on. But all of these things contribute to the diversity we see. Perhaps in a future essay…?