Outer Cape Tours guide Dennis Minsky is perfectly suited to lead his ecological-based walks, Railway to a Unique Ecosystem and Bay Creatures Great and Small. A biologist and Provincetown resident since 1968, Dennis began his career as a Cape Cod National Seashore field biologist in 1974, when he helped start a seabird nesting protection program. In 1985 he created an environmental studies program for middle schoolers that emphasized the Hudson River ecosystem, a program he continued for 20 years. Minsky has been a naturalist for the Dolphin Fleet Whale Watch and the Provincetown Center for Coastal Studies since 1995, educating people about whales and the ocean’s ecosystem. He is an expert birder, a member of the town’s conservation commission and a regular columnist for the Provincetown Independent.