BLACKWATER NATIONAL WILDLIFE REFUGE: 2145 Key Wallace Drive, Cambridge, Md.; http://www.fws.gov/blackwater or (410) 228-2677. Parking fees: $3 for cars, $1 for bicycles. No parking fees for people holding an Interagency Annual Pass, which covers admission to national parks and wildlife refuges. Open daylight hours.
EVENTS: The refuge hosts free guided bird walks one Saturday every month in spring and fall. On May 27, the refuge will throw a party to celebrate the 100th anniversary of the birth of Rachel Carson, who lived in Maryland and is credited with helping to start the modern environmental movement with her book “Silent Spring,” which detailed the effects of pesticides on birds including bald eagles.
GETTING OUTSIDE: Canoe, kayak and bike rentals are available in Cambridge. For a guided trip, try Blackwater Paddle and Pedal Adventures at (410) 228-7650, www.blackwaterpaddleandpedal.com or ’Peake Paddle Tours at (410) 829-7342, www.paddletours.com. For an unguided trip, rentals of kayaks, canoes and bikes can be found at Cambridge Cycle & Sport at (410) 901-8380. The refuge posts three popular paddling routes at the visitor’s center, with self-guided trips ranging from 3.8 miles to 10 miles. Feel like fishing instead? Fishing charters are available from Osprey Expeditions at (410) 991-8468, www.cdollarfishing.com.
Maggie Briggs, visitor services manager for the Blackwater National Wildlife Refuge, looks out at the refuge from the observation deck in the visitor’s center.
WHILE YOU’RE IN DORCHESTER: The University of Maryland gives free tours of its Horn Point Laboratory in Cambridge on Tuesdays and Saturdays from May through September. See how scientists monitor the health of the Chesapeake Bay and visit tanks where scientists raise millions of baby oysters, called spat. Tour information and directions are at (410) 221-8383, www.hpl.umces.edu/tours/index.htm.