A flash of red caught my eyes. What was that? I looked around the marsh plants, small trees, and mud of the wetland in Brazos Bend for the vibrant color, but couldn’t seem to find it. Not a cardinal, this bird only had a hint of red and now I had lost it. The only bird in sight was a medium-sized, generic blackbird, rummaging around the mud for what looked like bugs or twigs, or so I thought.
This generic bird turned its back to me and revealed its vibrant red epaulets with yellow trim. Unlike most birds, which have splotches of color here and there- a quilt of colorful feathers- red-winged blackbirds, Agelaius phoeniceus, look more like they’re wearing a carefully designed bird-evil villain outfit from the eighties (see images below). Like the rest of its species, the bird in front of me had an entirely jet-black body except for two precisely sized red-shoulder pads flanked with yellow.
This fascinating little creature bopped around the marsh, occasionally picking at the dirt or flying to another small island of mud few feet away. I was admiring its jerky movements when my focus was interrupted by a loud squawking that sounded like the noise that would come out of angelic songbird being strangled in a cartoon – somewhere between cheap plastic whistle and a kazoo. I looked to see who the loud-mouth(or should I say loud-beak) was and low and behold it was another red-winged blackbird. This one sat atop the highest dead branch in the marsh, and was making its presence known (this video shows a male doing the same display that I saw in Brazos Bend!). In fact, it wouldn’t stop. Every few moments, the shrill barking of this fashionable bird interrupted my bird watching.
Upon arriving home in the evening, I was eager to learn more about the red-winged blackbird and ran Google scholar search. Turns out I am not the only one interested in these passerines – there were over 20,000 Google scholar hits! It seems red-winged blackbirds are one of the most studied species in the avian world. And, what’s more, many of the most popular articles explored the peculiar squawk that punctuated my bird-watching trip.
The more I looked, the more I realized that two males I saw couldn’t have given me a more typical look into the world of red-winged blackbirds, especially the one calling from the highest point of the marsh. For red-winged blackbirds, their call and their position determines whether they can keep their territory, find a suitable mate, and try to deter their mate from sleeping around with the next red epaulets that catch their attention. In one study in Madison Wisconsin, Robert W. Nero followed 25 males and 50 females to learn about their behavior and his findings on male calls were quite remarkable. Not only do males have a simple rhythm they sing out for their potential female companions, they have a whole repertoire of songs, each for a different purpose. In the paper, Nero describes their “flight song,” given in flight to claim a territory or as a victory song after chasing away a competitor and their “song spread” which is given with a plumage display (see the fantastic photo of this huffed up stance below).
A different study using adult females from Linesville, Crawford County, Pennsylvania, tried to discern the function of the more romantic solicitations and their effectiveness on females. Recorded male calls were played over a tape recorder and the reactions of the females were observed. To show that they are ready for copulation, females respond vocally to the call then assume their “ready” posture – Tail up, legs flexed, bill pointed, and fluttering spread wings. Wowzers! I bet the sight of a room of female birds trying to balance in this bizarre stance was hilarious for Searcy and the other researchers.
After playing the precopulatory song – a long series of single note calls – and the regular male melody there were several findings. The females barely responded to precopulatory calls, but would take the position when the regular ole melody came from the tape recorders. As can clearly be seen in the bar graph below, it pays to be yourself males! Females don’t want the fuss of precopulatory grunts and catcalls; they want the genuine, natural male call. In fact estimating from the graph, it looks like the females are 5x more likely to respond to the song than the precopulatory call.
The truth is, like with many bird species (or at least as it should be J), females control everything regarding reproduction. This was emphasized in paper after paper. The female red-winged blackbird chooses who, what to respond to, when, which territories, and how many mates she wants. Try as they might the males are virtually helpless in persuading their partners to mate, to stay or to even show a bit of loyalty. One article, Female Control of Offspring Paternity in a Western Population of Red-Winged Blackbirds, followed red-winged blackbirds in three marshes of the Columbia National Wildlife Refuge in central Washington State. The findings – females are not loyal and there isn’t a darn thing the males can do about it. With a 35% rate of extra pair fertilization (78% of which were instigated by females who snuck away from the territory of their male “partner”), the interests of the sexes in this species are at serious odds. You might ask “snuck away”- these are birds we’re talking about aren’t we? Well yes, but most extra pair copulations occur because females leave their territory and specifically select territories with plenty of friendly male neighbors. To counter this behavior, males exhibit “mate guarding” behavior to try and prevent other males from encroaching on their territory, by mating more with the females on their territory to dilute the sperm count of their competitors, by attacking male intruders, and by seeking out territories which will attract the most females. Despite these behaviors and their aggressive nature, as can be seen in the graph, most of their efforts are in vain. Extra pair copulations still occur at a significant rate, especially directly prior to egg laying.
So what does determine male success? There must be some reasoning behind female preference and for all the within pair copulations there must be something that sparks the females’ attraction. One study in the Turnbull National Wildlife Refuge in Cheney, Washington demonstrated that male success is largely dependent on their red shoulder ornaments. In The Role of the Epaulets in the Red-Winged Blackbird, (Agelius Phoeniceus) Social System, Douglas Smith explored the role of epaulets by covering the epaulets with black paint and observing the social effects. Epaulets are prominently displayed in many of the male red-winged blackbirds behaviors including the “a) song spread; b) bill-up boundary; c) flight-song display; d) fluttering-flight display; e) crouch; f) pre-copulatory display; g) defensive flutter and, h) sexual chasing. The male directs all but the sexual chasing and precopulatory displays- to both females and males (Smith, 1972).” Following 89 males between 1969-1970 they found that the males were pretty much helpless without their epaulets. In their study, 30 males with blackened epaulets lost territories as opposed to only 3 without blackened epaulets losing their territory. Additionally only 17 males with blackened epaulets managed to keep their territory, but 37 of the males with normal epaulets kept their territories (see table below for the summary of the results). Without a territory, males are less likely to attract females or achieve reproductive success. It is all in the looks!
The importance of appearance and feather patterns was further supported in a study by Noble and Vogt in 1935. They successfully demonstrated that males would attack stuffed red-winged blackbird males located in their territory, and if a stuffed female bird was placed near their territory, they tried to mate with the bird-doll. Some say actions speak louder than words, but for these birds, looks speak louder than actions, words (or really calls) and just about anything else.
After reading through all of these studies, I realized I had just barely scratched the surface of information available about these fascinating birds. I covered the areas most interesting to me – bird calls, mating behavior, unique coloring- but I highly encourage searching through the 20,000 articles for more information. This species provides a whole lot to chirp about. Who knows, you might even be able to impress your roommates with red-winged blackbird information like I have*. So until next time, have a fowl day!
My roommates have now banned me from discussing anything related to birds, birding or even binoculars. Yikes!
- Smith, Douglas, and Reid, Fiona 1978. Roles of the Song Repertoire in Red-Winged Blackbirds. Behavioral Ecology and Sociobiology 5.3: 279-290. Print.
This paper discusses the many calls of the red-winged black bird and their function in various social interactions.
- Smith, Douglas 1972. The Role of the Epaulets in Red-Winged Blackbird, (Agelaius phoeniceus) Social System. Behaviour 41.3/4: 251-268. Print
This paper studies the role of epaulets in red-winged black birds by experimenting and blackening the epaulets of select birds.
- Nobel, G.K, and Vogt, William 1935. An Experimental Study of Sex Recognition in Birds. The Auk 52.3: 278-286. Print.
This paper discusses the factors that go into sex recognition of male and female red-winged blackbirds.
- Searcy, W. A 1989. Function of Male Courtship Vocalizations in Red-Winged Blackbirds. Behavioral Ecology and Sociobiology 24.5: 325-331. Print.
This paper compares courtship vocalizations of red-winged blackbirds and evaluates which calls are most effective in stimulating females.
- Gray, Elizabeth 1996. Female Control of Offspring Paternity in a Western Population of Red-Winged Blackbirds (Agelaius phoeniceus). Behavioral Ecology and Sociobiology 38.4: 267-278. Print.
This paper explores the behavior of female and male red-winged blackbirds that lead to the paternity of offspring, including within pair mating, extra pair mating and defensive mechanisms.
- Nero, Robert 1956. A Behavior Study of the Red-Winged Blackbird. The Wilson Bulletin 68.1: 4-37. Print.
This paper discusses the behavior of red-winged blackbirds in mating, nesting, feeding, and other social trends.