Written by Sarah Dugan, Kroening Nature Center Naturalist
The sights and sounds of migrating birds are a sure sign of spring in Minnesota. Some of the most familiar and distinctive returners in the neighborhood are the red-winged blackbirds that call across the prairies as they jockey for territory.
In winter, the central and southern U.S. host large flocks, with numbers in the millions. These flocks start to disperse in the spring as northern populations move up to breeding grounds like those in Minnesota. The males are the first to arrive, and they immediately begin establishing their territory. Generally preferring wet, swampy areas, red-winged blackbirds will also breed in open prairies with sufficient tall grasses and reeds to shelter nests. Showing off their red shoulder patches and calling with a coarse trilling ‘conk-la-REEE,’ males claim up to a half-acre or so of territory each. Many return to the same area year after year, with older males tending to have the best territories.
Females return north a few weeks later in the spring and select a mate, based at least in part, on the quality of his territory. One male may have several females nesting within his territory, though genetic testing indicates that up to a quarter of the eggs in a given male’s territory may not be his. Females seem to benefit from having additional nesting females nearby as they can share in the defense of the territory and disperse the impact of predation.
Female red-winged blackbirds are the nest-builders, weaving together plant fibers a few feet above the water or ground and lining their nests with mud and dried grass. The drab coloring of the females contrasts sharply with the dramatic black and red of the males, but allows for excellent camouflage during incubation and rearing. Females spend three to four weeks incubating and rearing a brood of fledglings and can raise up to three clutches of eggs each season.
Once eggs are laid, both females and males will defend the nests from predators such as raccoons, snakes, foxes and skunks. Males are known for their aggressive defense of their territories and nests. They may spend a quarter of their time fending off both rival males and potential threats, including humans.
In contrast to their behavior in nesting areas, red-winged blackbirds are not especially competitive over food. Their diet consists of mostly insects when available, and seeds and grains the rest of the year. Even during the breeding season males will flock together when looking for food, in neutral non-nesting territory. At these times they will reduce the appearance of their red shoulder patches to minimize conflict.
Visit North Mississippi Regional Park this month to hear and see red-winged blackbirds and many other returning birds. April programs at Kroening Nature Center:
Nature Tots: Wiggling Worms · Saturday, April 5, 10:30-11:30 a.m. | Free | Ages 2-6 with an adult | Activity #15437 | Discover what there is to do down in the dirt! Go for a worm hunt outside to see what’s keeping worms so busy. Then investigate worms up close while using a magnifying glass to find out how they are able to move through the hard earth.
Birdwatching at the Heron Rookery · Thursday, April 10, 10-11:30 a.m. and 12:30-2 p.m. | $9/person | Ages 18+ | Activity #17688, #17689 | Join a naturalist at Marshall Terrace Park to learn about Great Blue Herons and observe their fascinating behavior. Binoculars and a spotting scope will be available for use.
Homeschool Day: Water Quality · Thursday, April 10, 12:30-2:30 p.m. | Free for Minneapolis residents | Ages 5-12 | Activity #15468 | Learn the importance of water quality and how it affects life in and around the Mississippi River. Take water samples to determine the health of the river and help keep the Mississippi clean and healthy by going on a trash collecting mission along the river.
Family Funday: Finding Our Way · Saturday, April 12, 10:30 a.m.-noon | Free | All Ages | #15448 | How do birds know where to go when they migrate? How do pollinators find nectar? Explore how different animals navigate in their environments and find your own way through a simple challenge course.
Nature Art: Art on the Landscape: Rocks and Mud · Saturday, April 19, 1:30-2:30 p.m. | Free | All Ages | Activity #13217 Sculpt and create with the nature around you! Collect rocks, sand, soil and mud. Then sculpt them to create an art installation outside.
Nature in Focus: Water Quality · Saturday, April 26, 1-2:30 p.m.| $9/person | Ages 18+ | Activity #15717 How do we know if our waterways are healthy for animals and humans? Learn about human impacts on local water quality, explore data on water quality trends in Minneapolis parks, and head outside to test water in the park.