Shorebirds increase greatly in numbers in August, and later in the month adults of many species are replaced by young birds in juvenal plumage. Some of the adults may be in mid-molt, making identification trickier. During August, later arrivals like avocets, willets, buff-breasted and western sandpipers, and phalaropes add to shorebird variety. Other earlier migrants arrive from the north, among them certain flycatchers, warblers, thrushes, and orioles, and, by mid-month, puddle ducks such as teals The relative independence of young birds of other species leads to widespread flocking—including, for example, among swallows, who form long lines along utility wires and swirling masses over the marshes. A few more breeding species begin to desert our latitudes, led by the first migrant bobolinks and orchard and Baltimore orioles. Darting companies of migrant nighthawks appear during late afternoons and twilights later in the month. Waders such as egrets begin to throng in the big marshes, and the scarcer youngsters among snowy egrets and little blue herons may appear in odd spots around the state. Huge roosts of staging terns appear on beaches and sandbars along the Lake.
By the end of the month, more migrant warblers, thrushes, and tanagers from the north are beginning to appear. Mostly silent (although in favorable conditions some whispering versions of their songs may be delivered), their journey more leisurely and protracted than in spring, and in many cases wearing duller winter and juvenal feathers, these birds pass us more inconspicuously during fall, even though their numbers, augmented by young fledged during the summer, are far greater. Finding and identifying them is a challenge relished by birders who have mastered these species during the spring