When families feel strong enough – and the weather conditions are right -- they take off for their long journey in late summer to their non-breeding wintering grounds, mainly the rainforests and agricultural regions of Brazil and parts of northern South America.
The migration route for eastern U.S. families takes them mostly overland, down Florida and the Caribbean islands or across the Gulf of Mexico to Central America. Weather can complicate the migration and is a major cause of mortality, just as extremely cold or hot weather during the breeding season can kill birds. Purple Martins are leisurely in migration. They will stay overnight along the way in large staging areas in treetops or sheltered, reeded islands.
Tracking martins with geo-locators has been done only recently. Research indicates the martins fly 200 to 250 miles per day, making a trip of up to 3,000 miles in about 15 days. The fastest migration on record is 13 days by a bird who flew about 340 miles per day.