Birding Through the Seasons - August
By early August, most parent birds and their offspring have wandered from their home territories to food-rich areas anywhere in the state. Songbird activity shifts from reproduction and territoriality to preparation for winter or migration, although a few birds, such as goldfinches, waxwings, cardinals, and Mourning Doves, are finishing up late nesting attempts in August.
In very early August, some species that nest multiple times are still prominent in fields. It is not usual to hear the double-noted song of the Indigo Bunting or the "bouncing ball" song of the Field Sparrow when other songbirds have fallen silent. Southward migration begins with the newly-produced young this month for most species and will peak in September as adults join the cycle.
Along with early shore-birds, swallows are among the earliest birds to move south. After their nesting activities and just prior to their departure, Tree, Barn, Cliff, Northern Rough-winged, and Bank swallows and Purple Martins can be seen gathering in flocks over bodies of water foraging on flying insects or perching on telephone lines in preparation for their migration. They often take dust baths in barnyards, dirt roads, and driveways.
Shorebirds (sandpipers, plovers, turnstones, knots, dowitchers and phalaropes), nesting in the vast Arctic regions of Canada, reach their peak migration movement during the month of August. Although shorebirds typically concentrate on extensive mudflats not widely available in Pennsylvania, a few locations provide reliable viewing. After a hard rain, some agricultural fields become flooded enough to provide good stopover habitat for shorebirds.
Hummingbirds, flycatchers, and warblers also begin heading south, and look for daytime movements of nighthawks late in August.
As August winds down, some of the first raptor movements are noted along the state's ridges, notably osprey and bald eagles. The fall is the best time of year to see raptors (hawks, eagles and falcons) in Pennsylvania.
Pennsylvania Game Commission