Cape Cod Bird Nerd Gretchen Moran Towers will lead a 1 ½-mile spring walk at 10 a.m. May 21 on the Historical Society of Old Yarmouth’s 50-acre preserve trails in Yarmouth Port. Meet at the Gatehouse behind the Yarmouth Port Post Office on Route 6A at 9:45 a.m. For adults and children 12 and up, 20-person limit. $10 reservations available at www.hsoy.org/events or HSOY Facebook page.