The focus of the baseline is on the intertidal areas of the study area rather than the inland habitats, as it is the intertidal which has the most potential to be affected by maintenance dredging. Bird count data have been collected for the Thames Estuary for a number of years. This data, along with information from the Natura 2000 citations, has been analysed to provide an overview of the overall waterbird assemblage on the Estuary.
Key species on the Thames Estuary include avocet, black-tailed godwit, dark-bellied brent goose, dunlin, European white-fronted goose, gadwell, grey plover, knot, lapwing, little grebe, oystercatcher, pintail, redshank, ringed plover, shelduck, and shoveler. Broadly speaking, the extensive mudflats and saltmarsh present within the study area provide some of the most important feeding grounds within the Thames Estuary as a whole. It is likely that the distribution of waterfowl is linked to the presence of productive mudflats in these areas which provide key prey items for waterfowl. In particular, the distribution of dark-bellied brent geese is probably governed by the distribution of eelgrass and green algae.
Relatively few alerts have been triggered for the key waterfowl species within the Thames Estuary and Marshes SPA indicating that the site is overall likely to be in good condition. However, a greater number of alerts have been triggered for the Benfleet and Southend Marshes SPA.