This hawk-watching tour was arranged by the Costa Rican National Museum. Sanchez directed the tour buses to this parking lot near Costa Rica's Caribbean shore because of the patches of rainforest nearby. The traveling birds roost in the trees overnight and, as the morning sun warms the earth, catch an early updraft and soar onward. Most of the birds passing this point are broadwing hawks and turkey vultures, with a few Mississippi kites, northern harriers and sharp-shinned hawks mixed in. On a good day, Sanchez estimates that 12,000 raptors cruise over this parking lot.
Most species seem to make the journey without eating, stopping only to rest at night.
Sanchez calculates that they can make up to 100 miles a day, meaning that some could overfly Costa Rica entirely. Unlike migrating waterfowl and songbirds, raptors take it easy, flapping their wings just enough to catch a thermal and then riding the current. The broadwing hawk resides from Guatemala to Brazil and migrates to the temperate zone every year to breed and raise young. Another migrant, the Swainson's hawk, is a prairie bird that makes an annual round trip of 11,000 to 17,000 miles from the American West to the South American pampas and back. The return migration heralds the resumption of showers.