If birds are your bag, visit this interesting little nonprofit center, where you can learn about the National Audubon Society's success in bringing puffins and other rare Maine seabirds back to historic nesting islands in a project lasting decades. There are exhibits, souvenirs and films. In July and August, there are special science programs specifically aimed at kids on Thursdays, and science lectures on Wednesdays.
Ask here about summer boat tours that can take you to view the fledgling puffin colonies at Eastern Egg Rock. Different companies run trips from Boothbay Harbor, Port Clyde and New Harbor; prices range from around $50 to $80.