The John Heinz National Wildlife Refuge at Tinicum is located in Philadelphia, Pennsylvania, about a mile from the Philadelphia International Airport. The refuge was created in 1972 to protect the last 200 acres of a once 5,700 acre freshwater tidal marsh, known as Tinicum Marsh, in Pennsylvania. The tidal marsh provides important habitat for over 300 species of birds, as well as fox, muskrats, fish, frogs, and a variety of plants. Several plant species from the refuge have been identified as being particularly useful for making phenological observations and are listed below.

The John Heinz National Wildlife Refuge provides important wintering habitat for migratory birds, especially those that use the Atlantic Flyway. It also provides a home for the state endangered red-bellied turtle and the coastal leopard frog. Warming temperatures and potential changes in precipitation patterns may alter the way in which the John Heinz NWR staff manages the Refuge for these animals.