Where do the swallows come from while heading to San Juan?

The swallows that head to San Juan, particularly the famous cliff swallows, migrate from their breeding grounds in North America, primarily from regions in the western United States and Canada. Each year, they travel thousands of miles south to winter in warmer climates, including parts of Mexico and Central America. Their journey typically coincides with the changing seasons, as they seek suitable habitats for feeding and nesting. Upon arrival in San Juan, they often gather around specific locations, such as the historic San Juan Capistrano Mission.