The Common Yellowthroat is a somewhat secretive warbler, frequently heard more than seen. It can be found all over the U.S. during breeding season in swamps, marshes, and wet thickets. Look for it locally in the Edmonds Marsh, which is its best habitat in Edmonds. For many years it was seen less commonly in the marsh but in the last few years it has become a breeding bird at that location.
There is a race of the Common Yellowthroat that is a year-round resident on the Rio Grande River delta of Texas. Other than that, the U.S. population is migratory and winters in southern Central America and the Caribbean. Both spring and fall migrations are spread over a long period. This species migrates at night.
The Common Yellowthroat feeds mostly on insects. Its diet includes dragonflies, damselflies, mayflies, beetles, grubs, caterpillars, moths, flies, aphids, ants, and leafhoppers. It also eats spiders and a few seeds. It forages in marshes and among other types of dense, low growth. It searches for insects on the surface of plants and sometimes forages on the ground.
Male courtship displays include flicking the wings and tail and following a female closely. The male also performs a flight display that involves ascending 25-100 feet in the air and returning to another low perch while he calls and sings. This warbler prefers to nest low to the ground. Its nest is typically no more than three feet above ground on tussocks of briers, grasses or shrubs. In marshes the nest is built among cattails, sedges, or bulrushes. The female builds a bulky open cup of weeds, grass stems, sedges, ferns, or bark. The inside is lined with finer materials. The female incubates her 3-5 eggs for about 12 days. Both parents feed the young. The nestlings leave the nest after 8-10 days but they remain dependent upon their parents for a much longer period. The Common Yellowthroat typically has two broods per season.
The male, with its broad black face band, has been described as a masked highwayman. The female is a drabber bird, but shares the distinctive yellow throat of the male. As is the case with many bird species, the young can be difficult to identify if not in the company of a parent.
As I mentioned in an earlier column about Wilson’s Warbler, there are many collective nouns for any group of warblers. They include bouquet, confusion, fall, and wrench of warblers. There is no collective noun specific to this species. The oldest known Common Yellowthroat was 11 years and 6 months of age.
Although the Common Yellowthroat is numerous, its population has experienced a decline of about 1 percent per year between 1966 and 2014, which is a cumulative decline of about 38 percent. The current global population, based in Canada, the U.S. and Mexico, is estimated at 87 million. While it is considered to be a species of least concern for conservation purposes, the Common Yellowthroat is vulnerable. The Brown-headed Cowbird frequently parasitizes its nests. Its larger chicks can out-compete its warbler nest mates for food. Degradation of wetlands and their conversion to urban or agricultural uses are problematic for this warbler. Since the species relies on insects, poor water quality, pesticides, and other pollutants can impact it. Even though there are no management efforts to protect the Common Yellowthroat, it is thought that it benefits indirectly from efforts to enhance waterfowl populations.
Birders and ornithologists describe the Common Yellowthroat song as wich-i-ty wich-i-ty wich-i-ty. You can listen to it here: http://www.xeno-canto.org/325260.
— By Carol Riddell
Carol Riddell manages the bird education displays, on behalf of Pilchuck Audubon Society and Edmonds Parks & Recreation, at the Olympic Beach Visitor Station.