Red Winged Blackbird

Content for this page researched and created by Thomas Secor

Red Winged Blackbird
Photo by A. MacKenzie

The red-winged blackbird (Agelaius phoeniceus) is a medium size blackbird that is found all across North America (Avian Web). It is on average 22cm long with a wingspan of 30 to 37cm. It weighs between 41.6 to 70.5 g and has an average lifespan of 2.14 years (Animal Diversity Web). It has a strong bill and somewhat upright posture. A summer male is black with a bright red shoulder patch. This shoulder patch is bordered by yellow in most of its subspecies. A winter male is also black with a red shoulder patch but it shows brown feather tips throughout the black body. The female is streaked throughout but has a white streak on its head, or supercilium. The top half of the bird is brown and streaked, the face and the underparts are pale with dense streaking, which is very broadly on the breast and upper belly. The female also has a poorly developed red shoulder patch (National Geographic).

There are an estimated 200 million red-winged blackbirds that range from Southeast Alaska and Canada across the lower 48 states and also well into Central America (Chipper Woods). While they are migratory, they can overwinter as far north as British Columbia and Pennsylvania (AvianWeb). The red-winged blackbirds are among the earliest spring migrants (Life Histories). Around 26 subspecies of red-winged blackbirds have been recognized, 14 of which are in North America (National Geographic). It may be the most abundant North American native bird (Wildscreen Arkive).

Male and Female Red-Winged Blackbird
Photo by J. Anderson

Red-winged blackbirds inhabit all sorts of open spaces, such as wet meadows, cattail marshes and even roadsides. Their favorite habitats are the cattail marshes and other wetlands where they eat the seeds and insects (ODNR Wildlife). Studies on food availability have shown that in a marsh that is surrounded by woods, female red-winged blackbirds deliver a greater amount of food per hour to their nestlings than females who nest at a marsh surrounded by agricultural land. Also, the male red-winged blackbirds care is less important to the nestlings in the woodland marsh than in the agricultural marsh. The study also found that males at the woodland marsh had over twice as many mates than the males at the agricultural marsh (Whittingham, Robertson).

Although 26 subspecies are recognized, most of them are poorly defined (National Geographic). Red-winged blackbirds and tricolored blackbirds overlap in California. A male tricolored blackbird is distinguished by an overall glossier plumage and a white border around their shoulder patches. A female tricolored blackbird is darker, like a charcoal-gray with less streaking than the female red-winged blackbirds (Cornell Lab of Ornithology).

Red-winged blackbirds forage while walking on the ground, and outside of the breeding season the blackbirds usually forage while in flocks (Audubon). They mainly eat insects in the summer and seeds, which include corn and wheat, in the winter. The blackbirds sometimes feed by probing at the bases of aquatic plants with their bills. They pry the plant bases open to get the insects that are hiding inside. During the fall and winter the blackbirds eat weedy seeds such as cocklebur and ragweed. They also eat sunflower seeds and waste grains (Cornell Lab of Ornithology). During the non-breeding season, the red-winged blackbird has an ability to damage important crops such as corn (Birds of North America).

Red-Winged Blackbird in flight
Photo by A. Reding

A study found that in food-deprived rapidly feeding red-winged blackbirds, pairs of the non-deprived birds also increased food consumption. The blackbirds also showed clear differential preferences for novel food based on what the males were consuming. This study can help explain the red-winged blackbirds’ tendency to locate and damage crops when they are vulnerable (Mason, Reidinger).

A study on how the red-winged blackbirds eat returned interesting results. Food was placed in holes, or on the ground. The birds were in one of two groups that would be rotated, as would the food placement. The study found that the birds hunting for food on the second day did so more efficiently by using long distance scanning instead of inspecting each of the holes closely. The red-winged blackbirds hunting habits are also affected by previous experience, they will repeat strategies that worked for them before. The blackbirds also use both locational and visual cues of prey and will learn to use them while foraging for their food (Alcock).

Both male and female red-winged blackbirds have more than one partner (Birds of North America). The male red-winged blackbirds will do everything they can to be noticed (Cornell). They will perch on a high stalk with their feathers fluffed to defend his territory and attract a mate (Audubon). The blackbirds call is called a “chuk” the males can use this to attract mates while also flashing his bright red shoulder patch (National Geographic). Males can defend up to 10 females in their territory. The males can attack much larger birds, such as crows and ravens while defending its territory (Avian Web). Females can have up to three broods a season (ODNR Wildlife).

A study has found that the red-winged blackbirds are more likely to nest in sites that have

Red-Winged Blackbird sitting on branch
Photo by D. A. Mitchell

higher vegetation durability, deeper surrounding water and that are closer to the water’s edge. The red-winged blackbirds nesting site choice impacts breeding success (Ozesmi, Mitsch). The female red-winged blackbird’s feeding rate decreased through the nesting season. The female and male red-winged blackbird’s feeding rates are independent. Also, nestlings fed by both parents receive more food than nestlings fed by just one parent (Yasukawa, Mcclure).

Another study has found that 44% of male red-winged blackbirds had more than one female nesting simultaneously in their territory. There was no cost in paternity for males guarding two or more females. Also, extra pair fertilization had little effect on the relationship between fledgling success and number of mates and appeared to have a minimal impact on the overall intensity of sexual selection of males (Westneat). Breeding success is related negatively with female breeding density within territories and positively related to territory quality. The same study  found that some female red-winged blackbirds specifically choose nesting sites that give lower reproductive success and that this selection may be related to their  getting a higher quality male (Weatherhead, Robertson). Females can also be aggressive to other females to deter their settlement and also to defend nest sites. The main aggression seen in female red-wing blackbirds are chases which have a clear winner and loser (Cristol, Johnsen).

Each female lays 3 to 5 eggs in a set in their nest (Life Histories). A study on the eggs has found that the nestling’s complexus mass, or body mass increases with laying order. Also, the nestling yolk testosterone concentration increases with laying order (Lipar, Ktetterson). Another study on nestlings and eggs found that the rate of tissue production in red-winged blackbirds is highest early in the postnatal period, when the maintenance and thermoregulatory costs are relatively low (Oslon).

Red-winged blackbirds biggest threat are humans. Many of the birds are killed to protect crops. When the red-winged blackbirds swoop down into the rice plantations, grain fields, and corn fields, they are slaughtered in multitude (Life Histories). The birds are also occasionally a victim of brood parasites (Avian Web).

General References:

Bent, A. C. “Red-winged Blackbird.” 1958. Life Histories of Familiar North American Birds. Web. 21 September 2016. <http://birdsbybent.com/ch41-50/blackbir.html>.

Kaufman, Ken. Red-winged Blackbird. n.d. Web. 21 September 2016. <http://www.audubon.org/field-guide/bird/red-winged-blackbird>.

“Red-winged blackbird.” 2012. Wildscreen Arkive. Web. 21 September 2016. <http://www.arkive.org/red-winged-blackbird/agelaius-phoeniceus/>.

“Red-winged Blackbird.” 2000. Chipper Woods Bird Observatory. Web. 21 September 2016. <http://www.wbu.com/chipperwoods/photos/rwblackbird.htm>.

“Red-winged Blackbird.” 2006. National Geographic. Web. 21 September 2016. <http://animals.nationalgeographic.com/animals/birding/red-winged-blackbird/>.

“Red-winged Blackbird.” 2015. The Cornell Lab of Ornithology All About Birds. Web. 21 September 2016. <https://www.allaboutbirds.org/guide/Red-winged_Blackbird/id>.

“Red-Winged Blackbird.” 2012. ODNR Divison of Wildlife. Web. 30 September 2016. <http://wildlife.ohiodnr.gov/species-and-habitats/species-guide-index/birds/red-winged-blackbird>.

“Red-winged Blackbirds.” 2011. AvianWeb Beauty of Birds. Web. 30 September 2016. <https://www.beautyofbirds.com/redwingedblackbirds.html>.

Rosenthal, A. “Agelaius phoeniceus.” 2004. Animal Diversity Web. Web. 30 September 2016. <http://animaldiversity.org/accounts/Agelaius_phoeniceus/>.

Yasukawa, Ken and William A. Searcy. “Red-winged Blackbird.” 1 January 1995. Birds of North America. Web. 21 September 2016. <https://birdsna.org/Species-Account/bna/species/rewbla/introduction>.

Scientific References:

Alcock, John. “Cues Used in Searching for Food By Red-Winged Blackbirds (Agelaius Phoeniceus).” Behavior. Vol. 46. 1973. 174-187. Web. 25 September 2016. <http://booksandjournals.brillonline.com/content/journals/10.1163/156853973×00238>.

Cristol, Daniel A., Torgeir S. Johnsen. “Spring Arrival, Aggression and Testosterone in Female Red-Winged Blackbirds (Agelaius phoeniceus).” The Auk Vol. 111. Vol. 111. 1994. Web. 21 September 2016. <http://www.jstor.org/stable/4088527?seq=1#page_scan_tab_contents>.

Lipar, Joseph L., Ellen D. Ketterson. “Maternally derived yolk testosterone enhances the development of the hatching muscle in the red-winged blackbird Agelaius phoeniceus.” Biological Sciences. Vol. 267. 2000. 1456. Web. 25 September 2016. <http://rspb.royalsocietypublishing.org/content/267/1456/2005.short>.

Mason, Russel J., Russell F. Reidinger, Jr. “Effects of Social Facilitation and Observational Learning on Feeding Behavior of the Red-Winged Blackbird (Agelaius phoeniceus).” The Auk Vol. 98. Vol. 98. 1981. 778-784. Web. 25 September 2016. <http://www.jstor.org/stable/4085898?seq=1#page_scan_tab_contents>.

Olson, John M. “Growth, the Development of Endothermy, and the Allocation of Energy in Red-Winged Blackbirds (Agelaius phoeniceus) during the Nestling Period.” Physiological Zoology. Vol. 65. 1992. Web. 25 September 2016. <http://www.jstor.org/stable/30158243?seq=1#page_scan_tab_contents>.

Özesmi, Uygar, William J. Mitsch. “A spatial habitat model for the marsh-breeding red-winged blackbird (Agelaius phoeniceus L.) in coastal Lake Erie wetlands.” Ecological Modelling. Vol. 101. 1997. 139-152. Web. 25 September 2016. <http://www.sciencedirect.com/science/article/pii/S0304380097019832>.

Weatherhead, Patrick J., Raleigh J. Robertson. “Harem size, territory quality, and reproductive success in the redwinged blackbird (Agelaius phoeniceus).” Canadian Journal of Zoology. Vol. 55. 1977. 1261-1267. Web. 25 September 2016. <http://www.nrcresearchpress.com/doi/abs/10.1139/z77-165#.V-h1ZvArKUk>.

Westneat, David F. “Polygyny and extrapair fertilizations in eastern red-winged blackbirds (Agelaius phoeniceus).” Behavioral Ecology. Vol. 4. 1992. 49-60. Web. 25 September 2016. <http://beheco.oxfordjournals.org/content/4/1/49.short>.

Whittingham, Linda A., Raleigh J. Robertson. “Food Availability, Parental Care and Male Mating Success in Red-Winged Blackbirds (Agelaius phoeniceus).” Animal Ecology. Vol. 63. 1994. 139-150. Web. 25 September 2016. <http://www.jstor.org/stable/5590?seq=1#page_scan_tab_contents>.

Yasukawa, Ken, Judy L. Mcclure, et al. “Provisioning of nestlings by male and female red-winged blackbirds, Agelaius phoeniceus.” Animal Behaviour. Vol. 40. 1990. 153-166. Web. 25 September 2016. <http://www.sciencedirect.com/science/article/pii/S000334720580675X>.

Image References:

Flickr. 2012. Web. 25 September 2016. <https://www.flickr.com>.(Use via Creative Commons)
Adult Male Red-winged Blackbird (A. MacKenzie) (creative commons)
Adult Female and Adult Male (Focused) Red-winged Blackbirds (J. Anderson)(creative commons)
Adult Male Red-winged Blackbird (D. A. Mitchell) (creative commons)
Adult Male Red-winged Blackbird in flight (A Reding) (creative commons)