Billy Frank Jr. Nisqually National Wildlife Refuge (Refuge) is located at the southern end of Puget Sound in the Nisqually River estuary. This 1200 ha wildlife refuge was established in 1974 to protect one of the last relatively undeveloped estuaries in Puget Sound, and is managed by the United States Fish and Wildlife Service (USFWS). Roughly 400 ha of the estuary were diked for agriculture in the late 1800s, with this subsided farmland subsequently converted to freshwater wetland upon refuge establishment. The Nisqually River Delta (NRD) is now the site of the single largest estuary restoration project in the Pacific Northwest. Removal of the outer dikes in 2009 increased salt marsh habitat in southern Puget Sound by 50%, restored more than 35 km of tidal sloughs and channels, and re-established tidal flow to 360 ha of historic floodplain and delta. The ultimate goal of the restoration was to increase the capacity of the estuary in order to support wildlife such as waterbirds and native fish. In particular, the Nisqually fall Chinook salmon (Orcorhynchus tshawytscha) has been a species of concern for the Refuge and Nisqually Indian Tribe (Tribe) as it is currently listed as threatened under the federal Endangered Species Act (SSDC 2007, NCRT 2001). The River Delta Adaptive Management strategy in Puget Sound supports public investment in river delta restoration of lost tidal wetlands through strategic investment in restoration and monitoring (Simenstad et al. 2011, Cereghino et al. 2012, Lyons 2012). In particular, restoration monitoring forms the basis from which managers may develop an understanding of how actions affect complex ecological systems, and tests our understanding of ecological theories such as succession and competition for resources (Zedler 2005). The NRD draft restoration monitoring plan hypothesizes that large river restoration improves growth of salmon smolts by increasing the opportunity for salmon to access suitable habitat in the newly restored delta habitats, and increases capacity via greater availability of invertebrate prey at specific, critical times (Ellings 2011). The abundance and distribution of the diverse invertebrate communities (terrestrial, aquatic, benthic, and epifaunal) used by smolts varies spatially across delta habitats and seasonally during their outward migration (Mar-Aug). As of yet, the capacity of these habitats to support outmigrating juvenile salmon has not been studied in an integrated manner within the Puget Sound. Salmonids exhibit multiple habitat needs that are life-stage specific (Healey 1991). Furthermore, the timing and size of the juvenile outmigration may change Chinook density patterns in a way that suggests competition for rearing space (Simenstad et al. 1982, Levings et al. 1986, Healey 1991). As such, a diversity of life history strategies, including differences in outmigration timing, size at outmigration, preferred foraging habitat, preferred prey resources, and estuarine residence time, can be adaptive for juvenile salmon, and can promote resiliency to environmental change (Healey and Prince 1995, Bottom et al. 2005a). Recovery strategies may best be guided by restoring a diverse habitat mosaic where variation in the timing and production of invertebrate prey can ameliorate unfavorable conditions throughout other parts of the delta, and numerous foraging opportunities are supported (Healey and Prince 1995, Wigington et al. 2003). To obtain detailed knowledge about spatio-temporal variation in invertebrate prey communities with respect to the juvenile Chinook outmigration, we monitored seasonal invertebrate abundance and community structure at five habitat types associated with the salmon outmigration: forested riverine tidal, emergent forested transition, estuary emergent marsh, delta mudflat, and eelgrass. We related invertebrate prey densities and community structure to biophysical factors such as temperature, salinity, and vegetation characteristics at each site during the salmon outmigration season. This information allowed us to identify the relative importance and habitat-specific capacity of the five major habitat types within the NRD, and their contribution to foraging juvenile Chinook populations in the context of the broader landscape mosaic.