FIELD NOTES    At least 130 species of birds visit or breed in the coastal wetland that includes Potter Marsh. Hundreds of migrants arrive on the marsh in April and May, and rare travelers show up in fall. Watch for a wide variety of ducks and geese leading fuzzy offspring through the lacework of pools and channels in June and July. Red-beaked Arctic terns nest here after making their annual 10,000-mile migration from the southern hemisphere. Trumpeter swans breed and raise cygnets; bald eagles soar over the marsh in search of prey, sometimes harried by terns and gulls. Male red-winged blackbirds declare their territories. Moose often forage in the brushy fringes toward the mountains and are especially active in May and June during greenup. Beavers work the ponds near the brush. Several species of salmon arrive in mid-summer and can be seen where the creek flows under the boardwalk. Watch them school in the clear water.

HABITAT Potter Marsh offers an extraordinary glimpse into multiple habitats at once: flowing fresh-water streams, shallow ponds, marsh, bog, brush and forest. The sedge-shrouded pools, fed by three streams, offer excellent nesting grounds for dozens of bird species. As the land rises—the result of glacial rebound—the wetland dries into open bog and black spruce, and then transitions into brushy alder. A forest of cottonwoods, birch and white spruce—a portal into woodland life—rims this open area.

CULTURAL CONNECTION  Potter Marsh was created in 1917 by construction of an embankment for the Alaska Railroad. The 564-acre marsh marks the southern reach of Anchorage Coastal Wildlife Refuge, a state-managed protected zone that extends 16 miles to Point Woronzof.

VIEWING TIPS Spring and fall migrations attract scores of birds. Call the Anchorage Audubon’s bird hotline for reports of unusual birds seen in the marsh. (907-338-2473).

HELPFUL HINTS Dress warmly while walking the boardwalk even on sunny days; you’re exposed to Turnagain Arm’s brisk wind. Leave dogs behind to avoid disturbing wildlife and viewers.