RED-WINGED BLACKBIRD (Agelaius Phoeniceus)

River-Lab 5 Guide Manual

RED-WINGED BLACKBIRD (Agelaius phoeniceus)

Red-winged blackbirds are particularly valuable members of basin system communities. Their value relates to their intensive predation on insects, their spreading of cattail marshes, and their control of some aggressive plants.

Adult redwings are omnivorous, eating many kinds of animals (mostly insects and some spiders, snails and crustaceans) and plant seeds. Seventy percent of the redwing’s diet is animal protein, primarily from insects. The demands of their young stir redwing parents into their most active period of insect predation. Once hatched, the ravenous chicks require a tremendous amount of animal protein, mostly from insects such as ants and grasshoppers. It may take the parents 200 or more trips per day to keep up with the incessant demand for food. Such intense predation by redwings, for themselves and their young, helps keep insect populations in control¾a valuable contribution to basin productivity.

The great variety in their diet allows redwings to return to their northern habitats early. Although insects are not readily available before spring, early-arriving redwings can feed on seeds from weeds, grasses, and any other available grains. Twenty percent of the redwing diet is seeds from weeds¾a “population” best kept in balance for optimum basin productivity.

Redwings contribute nourishment to a basin system in two important ways: as their eggs and offspring become food for other animals, and as they increase cattail marshes.

Redwing eggs are preyed upon by raccoons and snakes (which may also eat the chicks). The young are vulnerable to hawks as well.

Redwings use the fluff of ripe cattail seed heads to line their nests. This nesting activity helps spread cattail seeds, and the spreading cattail marsh helps stabilize the river. At the end of their growing season, cattails decompose into a rich detritus in the still, shallow water. These nutrients feed millions of tiny and microscopic organisms, such as freshwater plankton, which in turn feed small fish and other small aquatic organisms, including insects. These increased nutrients are especially important to the exploding populations of young animals in the spring.

River-Lab 5 Guide Manual

RED-WINGED BLACKBIRD, cont’d.

Averaging seven to nine-and-a-half inches long, redwings are smaller than robins. Male redwings are black, with red shoulder patches (epaulets) edged with creamy yellow. The red patches are sometimes concealed under black feathers, leaving only the yellow margins visible. The male displays his red epaulets to declare his territory and attract a mate. The females are similar in size, but very different in coloration¾a dull, streaky brown with dark stripings underneath. The young resemble the mother in coloring, although the male youngsters have the red patches of their father. Redwings have two calls: “konk-ka-ree,” a harsh, warning cry, and the more musical “o-ka-leeee.”

Redwings are among the first birds to return from their southern winter residences, usually arriving in southern New England in March, although some have been observed in mid-February. The redwing male comes north first to stake out a territory in which he and a mate will be able to find enough food and nesting materials to raise a family. He aggressively drives out all other male redwings from his chosen territory. He is so intent on defending his territory that, when the females arrive three weeks later, he may at first chase them away, too.

Redwings are usually numerous in the shrubs and trees of marshes, swamps, and fields that are close to water. Redwing nests, often constructed of grasses and cattail fluff, are usually built among cattails or other wetland plants or in shrubbery near a river or marsh. Females and young are well concealed in cattails.

Redwing females lay three to five pale blue eggs (one inch long), spotted with a darker blue, brown, or purple. The mother will sit on the eggs just enough to keep them at the right temperature.

After twelve days of being fed intensively in the nest, the young redwings start finding food on their own. Their fast development and large appetites in each stage of their lives ensures that there will be no time when their basin system is not benefiting from the activity of redwings.