As birders, we have a tendency to sneer at common species, even disparaging them as “trash birds.” One of my birding resolutions for 2011 is to learn to appreciate all species, no matter how mundane. Learning more about their lifestyles is a step in that direction.
Even before I was a birder, I could identify the male Red-winged Blackbird. Found in shallow marshes and other wetlands around the country, the black bird with the red and yellow shoulders is a familiar sight. Even the little drainage pond at the end of our street, with its sparse patch of cattails, is home to a few of these noisy blackbirds.
It wasn’t until I started really looking at birds, however, that I learned the striped bird with the white eyebrow that I had considered “yet another large-ish sparrow” was actually the female version of the same species. Females often have colors and markings that keep them hidden while nesting and raising young. In the case of Red-winged Blackbirds, this makes total sense.
The males are highly territorial, and flaunt their red wing “badges” as a warning to other males not to trespass on their particular patch of reeds. They are very aggressive, attacking not only other birds, but even larger animals such as people and horses! Each male mates with two to four females, although some particularly virile males may have up to 15!
With each male busy defending more than one female, it isn’t surprising that the females do a bit of skulking of their own. They often mate with other males, laying a clutch of eggs with mixed paternity.
Clearly, with his attentions spread so thinly, the male can’t be expected to help out around the nest, and for the most part, he doesn’t. The females build the grass nests and do all the incubating. Once the eggs hatch, the “first wife” can count on some assistance with food for the three or four nestlings she is raising, but the rest of the females are entirely on their own.
The young leave the nest between 11 and 14 days after hatching but, like many offspring, expect parental handouts for another couple of weeks. The tired females must be relieved when their progeny finally strike out on their own, and often call it a year after that one brood. Other hardy souls volunteer to raise a second—or even a third—family that season.
While they may vacate the northern parts of their range in winter, here in Colorado, Red-winged Blackbirds are year-round residents. As omnivores, they are able to switch their breeding-season diet of protein-rich bugs and small vertebrates (especially dragonflies, mayflies, and other aquatic insects) to seeds and berries during the winter months. Especially during cold weather, entire flocks will descend on feeders and quickly gobble down every sunflower seed.
Because they congregate in large numbers during the winter, Red-winged Blackbirds can be a nuisance. Their voracious appetite for seeds extends beyond backyard feeders to include fields of grain; thus they are sometimes considered an agricultural pest. Additionally, their droppings provide a nutrient source for histoplasmosis, a fungal disease that also affects humans. While the birds themselves don’t seem to catch this disease, their beaks, wings, and feet can become contaminated. It’s a good idea to avoid areas where large flocks have roosted.
These drawbacks are easily balanced by the benefits these blackbirds provide. While the flocks do eat some crops, they primarily hang out in fields that have already been harvested, as well as feed lots and weedy areas. Plus, they eat thousands of insects. Any bird that eats both ragweed seeds and mosquitoes gets five stars in my book!
Considering the rate at which wetlands are disappearing, it’s a tribute to their adaptability that this species continues to thrive. The next time I visit our local nature center’s marsh, I’ll make sure to stop and enjoy the Red-winged Blackbirds.