Some birders speak of “spark birds,” species that caught their eyes and launched them as birdwatchers. Canadian Julia Zarankin, in her wonderful memoir Field Notes from an Unintentional Birder, describes her spark. On her first outing with a Toronto bird group, she spent a frustrating morning trying to achieve what she called “the trifecta” of raising the binoculars, focusing them, and finding the bird—before it flew off. Near the end of the outing, the group paused by a bush and the leader called out “Red-winged Blackbird.” Zarankin dutifully raised her binoculars and this time things went well. She got the bird in sight and gasped, stunned by what she saw, the scarlet epaulets. “I watched as the bird threw back its head, opened wide its beak and let out a sound so primal it left me marveling: this was as close as I’d ever stand to dinosaurs.” She was hooked. By a Red-winged Blackbird.
One of the most abundant birds in North America, the Red-winged Blackbird is an early sign of spring for many. Males arrive early and begin defending territories when the marshes are still encased in ice and snow, looking like dead zones. For this species, though, it is all about the territory. When the females arrive a few weeks later, they will choose their mates based in part on the quality of the territory—does it have good water, an abundant supply of insects, sturdy structural plants for nest sites? A particularly successful male will be able to hold down a territory that supports two or three females, each with her own nest. Thus, Red-winged Blackbirds are polygynous – a mating system where a male has two or more mates.
Females look strikingly different than the flashy males. They are smaller, and heavily streaked in dark and pale browns. Their modest plumage often baffles inexperienced birders, who can’t locate the bird in their field guides. Such camouflaging plumage is protective to the females, who alone will build nests, incubate eggs and feed nestlings.
As a teenager in the 1870s, early Minnesota ornithologist T. S. Roberts kept a bird journal. He recorded a quirky observation: on a visit to the Minnesota River sloughs (what today is the national wildlife refuge below the Mall of America), he came upon some female Red-wings hovering over the river, their legs hanging down. As he watched, the birds from time to time would grasp something in their claws. Upon inspection, he discovered numerous tiny minnows swimming near the surface. The birds were fishing like miniature osprey!
Red-winged Blackbirds are short distance migrators. Unlike warblers that fly to the tropics, blackbirds travel a few hundred miles south come the fall. A look at a range map shows that only the blackbirds in the northern two-thirds of Minnesota leave for the winter. Southern Minnesota retains its population. Having only to fly a short distance to the breeding grounds means that Red-winged Blackbirds can respond quickly to a change in weather, such as that a changing climate might bring. March 2012 had an early green-up and researchers noted that Red-winged Blackbirds arrived early, to capitalize on the emergence of certain insects.
Red-winged Blackbirds have a reputation for destroying agricultural crops. The Ojibwe recognized that hordes of hungry blackbirds could have a sizable impact on the wild rice harvest. Likewise, the birds in the past have devastated corn crops. Roberts writing in Birds of Minnesota, described inspecting a cornfield of 60 acres in southern Minnesota, where not a single ear of corn could be harvested. Still researchers know today that such damage comprises a limited portion of a Red-winged Blackbird’s diet. Seven-eighths of what the birds eat during the breeding season are harmful insects or weed seeds.
Yet even this plentiful species has undergone a decline since settlement days. In Birds of Minnesota, Roberts described the huge flocks seen in 1885 “rising at times with a sound of thunder.” At Heron Lake in southcentral Minnesota fall migrating blackbirds coming in to roost were in numbers “beyond computation—millions and millions.”
Citations:
Zarankin, Julie. Field Notes from an Unintentional Birder. (Douglas and McIntyre.)
Roberts, T. S. The Birds of Minnesota Vol. 2 (University of Minnesota Press.)
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