The common shelduck is a large, goose-like duck of estuaries and sandy coasts whose welfare depends on the health of intertidal mudflats rich in the tiny snail Hydrobia ulvae that forms its primary food.
Shelduck welfare is directly tied to intertidal mudflat quality and the abundance of Hydrobia snails. Coastal development that seals or reclaims mudflats eliminates core feeding habitat. Sea level rise without compensatory habitat creation will squeeze intertidal zones between fixed coastal defences and advancing sea. Oil spills on estuaries can coat feeding mudflats and poison the invertebrate communities that support shelduck populations.