Over 500 species of sedges in the genus Carex are found in the U.S. – over half of the world’s total. The great majority of these perennial, grass-like plants grow in the moist soil of meadows, marshes and bogs, as well as in high altitudes. Sedges are often distinguished from grasses by their stem, which is typically triangular in cross-section (“sedges have edges”). The flowers of sedges, each surrounded by a bottle-shaped bract, or modified leaf called a perigynium, are clustered on spikelets. The tips of these bracts persist after the seeds have formed, giving the spikelets a prickly appearance.
Because of their wide availability, the seeds are eaten by many kinds of wildlife, especially birds. Wild Turkeys, American Woodcock, Northern Cardinals, Horned Larks, Snow Buntings, Lapland Longspurs, ducks, rails, sparrows, redpolls and finches relish them. In the Northeast, Carex seeds, along with insects, are the most regular items in the diet of Ruffed Grouse chicks. Moose also occasionally feed on sedge seeds. (Photo: Longhair or Bottlebrush Sedge, Carex comosa)
You might guess from their name (both common and scientific) that American Tree Sparrows (Spizella arborea) inhabit wooded areas, but, in fact, you are much more likely to see them in small flocks on the ground in habitats more like their tundra breeding grounds — weedy fields, marshes and hedgerows. European settlers thought they resembled the Eurasian Tree Sparrow, and named them accordingly, but they are far different birds. They forage, feed and nest on the ground.
American Tree Sparrows do not breed in New England – they are strictly winter visitors and feed primarily on seeds and berries. They need to take in about 30 percent of their body weight in food and a similar percentage in water each day. Often they are observed scratching the ground for seeds, and occasionally beating their wings against grass seedheads in order to knock the grass seeds onto the ground where they quickly consume them. Look for American Tree Sparrows foraging beneath bird feeders during the winter months — come spring, they will disappear. (late edit: a photograph of a Swamp Sparrow accompanies this post. Although there is similarity in the appearance of Swamp Sparrows and American Tree Sparrows, this blogger should have taken more time when selecting the photograph for this post!)
Although the breeding and winter ranges of White-throated Sparrows overlap, most, if not all, populations are migratory. During their flight southward in the fall, White-throated Sparrows stop during the day to refuel on seeds, fruits and insects, if available. Winged Euonymus (Euonymus alatus), or Burning Bush, is an invasive shrub that, in addition to shading and crowding out native plants, produces vast quantities of capsules, each containing up to four seeds. White-throated Sparrows and many other bird species find these bright red seeds attractive, but unfortunately, they are of little nutritional value to the birds and other wildlife that feed on them. How ironic that these birds, whose health and migratory success may be compromised by the seeds of this invasive plant, are facilitating its establishment by dispersing its seeds.