Just minutes from downtown Everett, Spencer Island sits in the heart of the Snohomish River estuary, a wildlife-rich ecosystem where salt- and freshwater mix. Surrounded by snaking sloughs, this 400-acre island offers a slew of scenic delights, from glistening mudflats to glimpses of snowcapped peaks. And bird-watching opportunities here rank among the best in western Washington.

Starting by the water treatment plant, hold your breath and walk 0.4 mile down gravel 4th Street SE, coming to the trailhead proper at the old Jackknife Bridge. A paved trail leads right 2 miles to the City of Everett's Langus Riverfront Park. Continue straight onto the historic bridge. The bridge spanned nearby Ebey Slough from 1914 to 1980. In 1993 it was moved here to Union Slough, providing pedestrian access to Spencer Island. It is one of the last remaining bascule bridges (counterweight drawbridges) in the country.

Upon stepping foot on the island, come to a junction. The trail left follows a levee north to open-to-hunting (check seasons) Fish and Wildlife land. It terminates in 1 mile at a breach. Directly ahead is a short trail (often flooded in winter and spring), leading to a boardwalk providing excellent wildlife viewing. An old barn once stood here. A favorite subject for visiting photographers, it was toppled by a 2006 windstorm.

For the Spencer Island Loop, follow the levee trail south. In 0.2 mile come to a junction with the Cross Island Levee Trail, your return. Continue right, soon arriving at a bridge, one of several spanning breaches in the levee. These breaches were intentionally made by land managers to allow much of the island to revert back to a tide-influenced wetland. Scan the reeds, cattails, and sedges for myriad waterfowl and songbirds. Enjoy, too, the view east across the saturated flats to Mount Pilchuck and Three Fingers. Note the profusion of homes marching up the hills toward them. The constant buzz of traffic in the air also reminds you just how close the "civilized world" is to this wildlife refuge.

Continue hiking on the levee trail toward the southern tip of the island. Alders line the way, with an occasional birch or spruce adding a little arboreal diversity. The way then turns north, following alongside Steamboat Slough. Cross another breach bridge and come to a junction. The trail north dead-ends at an unbridged breach. Head left instead on the Cross Levee Trail, traversing wetlands teeming with life. Watch for hawks, herons, harriers, widgeons, and ruddy and wood ducks. Look, too, for bald eagles, river otters, coyotes, and deer.

In 0.5 mile the Cross Levee Trail leads back to the main trail. Turn right to return to the Jackknife Bridge.