Here’s your chance to see up to 35,000 birds in one day. That’s how many migrating birds can fill Upper Newport Bay this time of year as they fly south along the Pacific Flyway. The birds use the bay, one of Southern California’s largest and most biologically diverse estuaries, to rest and refuel on their journey to South America. The bay’s mudflats, salt marshes and islands provide plenty of food and shelter for a variety of shorebirds, wading birds and waterfowl. There are two easy ways to cycle from Irvine to the bay – via the Mountains to Sea Trail or San Diego Creek Trail. If you drive, you can park at the Peter and Mary Muth Interpretive Center.