There's one more weekend of the Skagit Eagle Festival in Skagit County, and it's going to be a doozy. The festival is based in Concrete, Rockport, and Marblemount, all on Highway 20 east of Mount Vernon. Bald eagles visit the Skagit River from late November to late January—the window aligns with when the salmon spawn and die (which make for a yummy eagle dinner). During the peak, it's possible to see 100 bald eagles from Highway 20 between Sedro Woolley and Newhalem.
In this final festival weekend, there is a free nature photography workshop from wildlife shutterbug Tim Boyer and a bonfire at an area ranch. The Concrete Center is a good starting point; they hand out maps and coffee, and they have clean public restrooms.
Both days, the Marblemount Hatchery gives tours from 11am–2pm, so you can trace the life cycle of the salmon from egg to eagle chow. Saturday at Challenger Ridge Vineyard & Cellars, there are wine tastings (for grownups) and s'mores (for everyone) during the live music sets. On Sunday, the last day of the festival, Tlingit dancers will stage a special performance at the Concrete Theatre.
In Rockport, the Skagit River Bald Eagle Interpretive Center points visitors toward highway pullouts with the best viewpoints and spots staffed by volunteer interpreters from the North Cascades Institute. Their advice for seeing America's eagle? Get outside before 11am (dawn is better) on a cloudy day, and use binoculars to focus on the river banks where eagles feed. At night, the eagles hang out in the biggest trees, and during sunny days they're likely to be in flight.