The Answer: Bolivar Flats near Galveston, Texas. This estuary hosts more than 10,000 shorebirds in early September–avocets, sanderlings, dunlins, ruddy turnstones, plovers, and sandpipers that stop to gas up before continuing an epic migration from Arctic breeding grounds to South America.
The Way: From the sandy parking area ($10 fee) at the end of Retillion Road, hike southwest along the trailless coast to the five-mile-long North Jetty, which attracts the most birds. A 20x power scope is best for glassing the mudflats. No scope? High tide brings the birds closer inland.