The Common Yellowthroat is a wood-warbler, the only species in its genus that regularly occurs north of Mexico. It is closely related to the Bahama Yellowthroat and to Belding's Yellowthroat of Baja California, and has sometimes been considered conspecific with these, as well as with other Mexican yellowthroats. Throughout its vast breeding range across most of North America south of the tundra, from southeast Alaska to Newfoundland and south into Mexico, it is one of the most abundant warblers, although in the arid Southwest it is usually found only around watercourses. It is also one of the most geographically varied warbler species, with more than a dozen subspecies named. Generally, birds from the northeastern and northwestern parts of the range tend to have darker upperparts than interior western birds. The extent and coloration of the underparts also varies geographically; western birds tend to be richer and brighter yellow than eastern birds.

Although typically associated with marshes, streamside thickets, wet meadows and other wetlands, Common Yellowthroats are also found in drier upland habitats as long as there is abundant and dense undergrowth for foraging and nesting. Yellowthroats eat primarily insects, gleaned from low vegetation or on the ground. The familiar song of the male varies between individuals and localities, but has a characteristic rhythm and form. Typically, three to four repetitions of a three or four note phrase are sung with one note sharply accented: “Wichity, wichity, wichity, witch” or “witch-a-wee-o, witch-a-wee-o, witch-a-wee-o.” The low harsh alarm call is also distinctive.

Male Common Yellowthroats perform song flight displays, especially during the late afternoon. The male gradually ascends into the air, calling to a height of 20 feet or higher, whereupon he utters a number of short sputtering notes, followed by song. He then drops back to the ground.

The female constructs a nest usually on or very close to the ground at the base of a shrub or clump of grasses. Sometimes she suspends the nest over water, attaching the nest to the stems of grasses, reeds or cattails. Occasionally, she extends loose material from the rim into an overhanging. The female incubates the eggs for about 12 days. Young yellowthroats leave the nest just eight days after hatching. They fly a few days later. Both parents tend to the young for an extended period up to 20 days. When a pair attempts to raise a second brood, as is common, the male sometimes assumes care of the first brood. Common Yellowthroats are frequent cowbird hosts. If a cowbird lays an egg in a yellowthroat’s nest, the yellowthroat sometimes builds a second nest on top of the parasite's egg and lays a new clutch.

Northernmost Common Yellowthroat populations are migratory and begin to leave the breeding range during August and early September. Occasionally some stragglers remain through the fall long enough to be recorded in Christmas Bird Counts.

Description:

Upperparts of both sexes are olive gray to olive brown. The throat, breast, and undertail coverts are bright yellow in males, and paler in females. The belly is whitish. The exact extent of the yellow and white of the underparts varies geographically. Males have a broad black mask across the forehead, enveloping the eyes. The band of whitish gray above the masks varies geographically and is yellowish in some races. Females lack the mask and have a faint buffy eye ring.

Recording credits:
Common Yellowthroat recorded by W. H. Gunn and can be found on Bird Songs of the Rocky Mountain States and Provinces.