There are two Mosier stops on the Mount Hood Loop of the Oregon Cascades Birding Trail:

Mosier Waterfront Park
Five miles of urban walking trails through wetland and upland habitats in wet-dry transition zone; resident birds include Great Blue Heron, Bald and Golden Eagles, Osprey, Blue-winged Teal, Wood Duck, Anna’s and Calliope Hummingbird, Cliff Swallow, and Vaux’s Swift.

Twin Tunnels
Mosier entrance of 4-mi paved trail route between Hood River and Mosier along restored Old Columbia Highway; mixed conifer forest, oak woodlands, grasslands, and basalt rock outcrops; Ash-throated Flycatcher regular near entrance.