The red-winged blackbird (Agelaius phoeniceus) is a common and widespread blackbird found in North and Central America. Known for the bright red and yellow shoulder patches on the males, these medium-sized songbirds are a familiar sight in marshes, wetlands, and agricultural areas across much of the continent. Red-winged blackbirds have an average lifespan of 2-4 years in the wild, but the maximum recorded lifespan for the species is over 15 years. So what is the oldest known red-winged blackbird? Identifying record ages for wild bird species is challenging, but with banding and sampling efforts by ornithologists over the years we can find examples of remarkably long-lived individuals. Here we examine what is known about the longevity and life history of red-winged blackbirds to try to determine the oldest on record.
Typical Red-winged Blackbird Lifespan
Most red-winged blackbirds only live for 2-4 years. There are many perils for a small songbird living in the wild and only about 50% survive past their first year. The survival rate climbs for those that make it to adulthood, but hazards like predators, disease, starvation and severe weather take their toll. Each year after maturity likely sees higher mortality, so red-wings over 5 years old are considered relatively long-lived. Banding studies have found the oldest wild individuals recorded surviving to ages 15 years and 5 months for a male and 14 years and 9 months for a female. However, it is quite possible even older birds have lived but evaded capture and study. Captive red-winged blackbirds have been known to live over 20 years in some cases, but lifespans are typically shorter without the protection and abundant food of life in captivity. So while we have records of wild red-wings over 15 years old, it seems likely older ones have existed.
Banding Studies for Age Records
Banding leg rings placed on wild birds for identification has long allowed ornithologists to track ages of individual birds over time. When a banded bird is recaptured or found deceased years later, the original banding date yields the minimum age of the bird if it was first banded as an adult. Banding of juvenile birds provides exact known ages. Organizations like the U.S. Geological Survey’s Bird Banding Laboratory accumulate extensive banding and recapture data over decades to provide insights into survival rates and longevity. Examining their red-winged blackbird records reveals the oldest known individuals. However, banding studies have limits. Small songbirds like the red-wing are difficult to capture and band compared to larger species. There are also geographic biases in banding effort, with more banding occurring in populated areas. Lifespan records will be biased toward areas with more banding activity. Thus it is quite possible even older red-wings have lived in regions with little banding. Only a tiny fraction of birds are ever banded, so there are likely many long-lived red-wings that have escaped notice.
Reproductive Success and Longevity
Why would red-winged blackbirds live over a decade and beyond when most birds are short-lived? Evolutionarily, longevity allows some individuals that survive the hazards of youth to gain many breeding years and greater reproductive success. Red-winged blackbird males don’t begin to breed until at least their second year when their distinctive plumage fully develops. Older males tend to acquire the best territories with abundant food and cover. With experience they are also more accomplished singers, defending territories and attracting mates. Female red-wings lay 3-5 eggs per clutch and may have 2-3 broods per season. More breeding seasons for long-lived females allow greater output of offspring over their lifetimes. Red-winged blackbirds engage in polygynous mating where each male mates with multiple females, so long-lived males can potentially sire many more young. Overall, longevity allows red-wings that survive the winnowing of youth to gain greater fitness by having more reproductive years to pass on their genes. Very long-lived red-winged blackbirds are likely highly successful breeders.
Habitat Quality and Food Availability
Typical environmental conditions may not allow most red-wings to achieve their maximum lifespan potential. Hazards accumulate over time and limit survival. But higher quality habitat with plentiful food resources improves longevity odds. Red-wings thrive in wetlands with cattails and other marsh vegetation. The seeds, shoots and insects these habitats provide are abundant and make foraging efficient year-round. Nearby fields, pastures and agricultural areas also supply seeds and grains when wetlands are frozen in winter. Ideal red-wing habitat has a diversity of robust food sources and cover. Red-wings that can acquire high quality defended territories in productive wetlands each breeding season should experience lower mortality and greater longevity. Milder climates may also aid winter survival. So the oldest red-wings likely benefit from occupying optimal habitats throughout their lives.
Differences Between the Sexes
There are some key differences between male and female red-winged blackbirds that influence relative longevity. As mentioned above, males don’t begin breeding until acquiring mature plumage at around two years old. This means only the males that survive to adulthood will have the opportunity to mate at all. In contrast, female red-wings start breeding in their first spring. So selection against frail juveniles is more intense in males. Males also go through a complete molt before winter, leaving them vulnerable while growing new feathers. This male molt again weeds out weaker individuals. Weather and habitat conditions during molting may impact male annual mortality. Additionally, the bright red shoulder patches and yellow borders of males make them more conspicuous to predators. This likely contributes to their lower survival rates compared to the more camouflaged drab females. The costs of display and competition for territories also carry risks for males. Together these factors may explain why the longevity record in the wild is lower for male than female red-winged blackbirds.
Clues from Related Blackbird Species
The lifespans achieved by related blackbird species may provide clues into the longevity potential of red-winged blackbirds. The common grackle (Quiscalus quiscula), another widespread marsh-dwelling species, has been recorded living to nearly 18 years in the wild. Likewise, the rusty blackbird (Euphagus carolinus) has been observed surviving over 15 years. Cowbirds, orioles, and other icterids also contain individuals banded as adults that have reached ages up to 15 years or more before recapture. So it seems likely red-winged blackbirds share with their relatives the capacity for similar exceptional long life under the right conditions. Intensive multi-year banding efforts targeting wetland habitats would be required to find the oldest red-wings still eluding detection.
Climate Change Impacts
Some evidence suggests climate change may be accelerating mortality and decreasing average lifespans in some bird species. Red-winged blackbirds could also be impacted by warming temperatures, changes in precipitation, and growing severe weather events. Droughts and dry conditions can reduce wetland food resources and quality. Milder winters with more freeze/thaw events can deplete seed sources and make feeding more difficult. More frequent heat waves and storms may increase mortality. Loss of wetlands to drainage and development also negatively impacts habitat. Aging red-wings with years of breeding experience may be better able to adjust and withstand these pressures. Younger red-wings may see reduced survival and longevity in the face of a changing climate. Continued monitoring of red-winged blackbird populations and longevity records will reveal whether climate change shortens potential lifespans for this widely distributed species.
Role of Predators, Disease and Contaminants
Predators, disease, and environmental contaminants take a toll on young red-winged blackbirds, but likely represent an accumulating threat over time to aging birds as well. Predators including snakes, raptors, mammals, and other birds hunt adult and nestling red-wings. However, older red-wings may become more skillful at evading predators over time. West Nile Virus emerged as an introduced disease in North America in 1999 and has killed many birds, including red-wings. Mosquito-borne diseases could produce annual epidemics reducing survival. Disease resilience from prior exposure may protect some older red-wings. Buildup of bioaccumulated pesticides and heavy metals in wetlands is another health threat, one that likely grows with age. So without human-caused contaminants, lifespans might be even longer. While many perils exist, the luckiest red-wings may still experience relatively low extrinsic mortality each year, allowing remarkable longevity.
The Role of Genetics
Another factor potentially contributing to exceptional red-winged blackbird longevity is genetics. Some individuals may have gene variants or inherited constitutions that boost survival attributes like disease resistance and environmental hardiness. These genetics may enable a small subset of red-wings to simply outlive most of their peers year after year. High mortality winnows young birds, leaving only the most robust individuals to potential old age. Chance combinations of multiple longevity genes may allow a small number of red-wings to achieve life spans at the maximum limits of their species’s biological potential. These rare individuals surviving over a decade and more represent the far end of the longevity spectrum permitted by the red-winged blackbird genome interacting with favorable environments. So while most red-wings succumb much earlier, exceptional genes enable record-setting lifespans.
Diet Quality and Foraging Efficiency
The ability to secure sufficient nutrition through skilled foraging may also contribute to extraordinary red-winged blackbird longevity. Wetlands supply an abundance of seeds vital to winter survival. Older red-wings likely become very efficient at extracting these seeds. Experience and learned behaviors like covering seeds with water to soften husks may give older birds feeding advantages. Young red-wings may struggle in harsh weather or when food is limited. Older birds may also dominate the best feeding areas. During the breeding season, protein rich aquatic invertebrates are key for producing eggs and young. Aging females with superior nesting and foraging areas may achieve higher reproductive success and self-maintenance. So above average foraging skills and diet quality from prime habitats may promote the potential for long life in red-winged blackbirds.
Does Captivity Increase Longevity?
The oldest known red-winged blackbird lived over 20 years in captivity. Does life in captivity inherently allow greater longevity than the wild? Captive birds experience fewer extrinsic mortality risks from predators, competition, disease, and weather extremes. Veterinary care and abundant food may compensate for aging. Thus lifespans achieved in zoos or aviaries may exceed what is possible in nature. However, the protective benefits of captivity likely come at costs, too. Confinement stress, reduced activity, and lack of environmental challenges may deplete resilience. Loss of complex foraging skills may also negatively impact health. So extremely long captive lifespans don’t necessarily reveal the maximum biological potential of red-wings. The oldest wild red-wings likely represent the upper lifespan limits of genetically robust individuals benefiting from high quality habitat and resources within natural environments. Captivity may preserve birds vulnerable to the winnowing of natural selection in the wild.
Conclusion
Determining longevity records and maximum lifespans for wild bird populations presents many challenges. However, the available data from banding studies suggests that red-winged blackbirds, while generally short-lived, can occasionally live over 15 years in the right circumstances. The longest lived known individual exceeded 20 years in captivity. Various factors like habitat quality, genetics, mate competition, and foraging ability likely promote long life for the rare older individuals that manage to evade hazards into old age. While most red-wings fall victim to predators, disease, weather extremes and other threats within their first few years, some with the right combination of traits and luck can achieve lifespans over a decade. Continued field research and banding studies focused on very old red-wings in key wetland habitats may one day reveal an individual exceeding 20 years in the wild. For now, the longest lived red-winged blackbird appears to be one that managed to survive over 15 years despite all the challenges facing a small wetland songbird.
