Red-winged blackbirds (Agelaius phoeniceus) are a common sight across much of North America. Males are known for the striking red and yellow shoulder patches they display during breeding season. They are also known for the constant noise they produce through vocalizations. Red-winged blackbirds have a wide repertoire of calls and songs that serve different functions.
Territory Defense
One of the main reasons red-winged blackbirds are so vocal is to defend their territories. Red-winged blackbirds are polygynous, meaning males mate with multiple females. Males defend territories both to attract females and protect nesting areas. Their territories are usually located in marshes or wet meadows and can range from 0.5-6 acres in size. Males actively defend these areas through vocalizations and aerial displays.
Some key territorial calls include:
- The conk-la-ree song – A musical song consisting of slurred whistles and gurgles used to attract females.
- The check call – A “check” or “tcheck” call used as an alarm call when predators or intruders enter a male’s territory.
- The chatter call – A rapid series of notes or clicks used in aggressive interactions against rival males.
Males will sing from perches within their territories and actively confront territorial intruders. More vocalizations are made during peak daylight hours when threats of intrusion are highest. The level of vocalizing is proportional to population density, with males in denser populations vocalizing more to ward off encroachment. This constant territorial defense is a key reason why red-winged blackbirds are such noisy neighbors.
Attracting Females
Another reason for the noisy ruckus is that male red-winged blackbirds are vocally advertising to attract females. As mentioned above, the conk-la-ree song is used to attract females to a male’s territory for mating. Males sing this complex and musical song repeatedly through the day during peak breeding periods. The song is easy to recognize based on its slurred whistling quality.
Studies have shown that males with larger repertoires of song types tend to be more successful at attracting females. Older males tend to have larger repertoires based on experience. Females have demonstrated the ability to distinguish between individual males based on song variations. The vocal fluency of males is therefore an important component of mating success.
In addition to the conk-la-ree, males will also use softer whistled call notes dubbed “perch coos” when a female enters his territory. The ongoing vocal courting is aimed at enticing the female to select him as a breeding partner. All this serenading adds up to a boisterous chorus during the height of mating season.
Group Foraging Calls
Red-winged blackbirds don’t just vocalize on their territories; they also call when moving and foraging in groups. In winter months, huge mixed flocks consisting of thousands or even millions of blackbirds can congregate and forage across wide areas. The flocks are made up of multiple blackbird species, including red-winged blackbirds, European starlings, common grackles, and brown-headed cowbirds.
These massive flocks exhibit well-coordinated movements and flight patterns. Individuals use call notes to maintain contact and cohesion within the flock. For example, members may use an ascending “zhee” call when taking flight and a descending “zrrr” call when landing. Syncing vocalizations helps the flock move in unison.
There are various other contact calls the birds use when foraging such as chip notes, prey-finding calls, and alert calls if predators are spotted. Without vocal communication, these large flocks would not be able to coordinate their activities as efficiently.
Weather Calls
Red-winged blackbirds also vocalize in response to weather events such as rain and high winds. For example, they give a distinctive descending whine call during rainstorms. They may also make a two-parted “teu teu” call when winds pick up. The function of these weather calls is uncertain but they could relate to territory defense, maintaining flock contact, or expression of annoyance!
Roosting Calls
At night, blackbirds congregate in huge communal roosts that can number over 1 million birds. As the birds begin arriving at the roost towards dusk, there is a constant ear-splitting noise of calls. These vocalizations may serve to advertise territory ownership within a roost. The birds also call noisily at dawn before departing the roost. These daily cycles of noise disrupt many a quiet neighborhood.
Non-Vocal Sounds
It’s worth noting red-winged blackbirds don’t just vocalize; they also make non-vocal sounds for communication. For example, males will produce a mechanical beak-clapping sound during courtship displays towards females. The clapping serves as a threat display against potential rivals. Males can also produce a bill-snapping sound when alarmed.
Conclusion
In summary, red-winged blackbirds are prolific vocalizers because sound serves many essential functions in their daily lives:
- Territorial defense
- Attracting mates
- Group cohesion and coordination
- Weather-related expression
- Roost communication
All the conk-la-rees, check calls, bill claps, and general ruckuses might be annoying to human ears, but it’s simply the red-winged blackbird’s way of navigating the world. Their incredible vocal variety and mastery helps them successfully thrive across North America. So next time you hear the din of the redwings, listen close to appreciate their diverse vocal talents!
