ABSTRACT Over the past 15 yr, an invasive cordgrass, Spartina alterniflora, has covered more than 5000 ha of tidal mudflats in Willapa Bay, Washington, threatening key shorebird habitat on the Pacific Flyway. Although chemical and mechanical control methods have been used to manage Spartina in Willapa Bay, little is known about how these methods affect subsequent use by shorebirds and waterfowl. During 2003–2004, four sites were monitored for 10-min periods for use by shorebirds [Dunlin (Calidris alpina), Western Sandpiper (C. mauri), Least Sandpiper (C. minutilla), Black-bellied Plovers (Pluvialis squatarola) and Long-billed and Short-billed dowitchers (Limnodromus sp.)] and waterfowl [Mallard (Anas platyrhynchos), Gadwall (A. strepera), American Wigeon (A. americana), Green-winged Teal (A. crecca), and Canada Goose (Branta canadensis)]. The four sites were bare mudflat (never infested with Spartina), tilled Spartina meadow (free of live Spartina and dead stubble), herbicide-sprayed Spartina meadow (10% living Spartina and 30% dead stubble), and an untreated Spartina meadow. Untreated Spartina meadow was rarely used by birds, with a mean of seven small Calidris sandpipers (peeps) and 0.8 waterfowl ha−1. Mean numbers of peeps and waterfowl observed using the herbicide-treated Spartina meadow were 62 and 16 ha−1, and the tilled Spartina meadow were 700 and 27 ha−1, respectively. Mean use of the adjacent bare mud site by peeps and waterfowl was 450 and 11 ha−1, respectively. The untreated Spartina meadow, sprayed meadow, tilled meadow and the bare mud site had mean densities of Black-bellied Plovers and dowitchers of 26, 24, 6, and 0 ha−1, and 0.8, 6, 0.3, and 0 ha−1, respectively. Our results demonstrate that, within several years of removal of invasive Spartina from mudflats in a large Washington estuary by either mechanical or chemical means, use by shorebirds and waterfowl will increase dramatically.