between the river mouth and the river witham, a large expanse of saltmarsh provides breeding grounds for common redshank, eurasian oystercatcher and reed bunting in the summer, and eurasian wigeon, mallard, common shelduck and common teal in the winter. birds of prey such as hen harrier and merlin feed on the flocks of linnet and twite, while the mudflats support dunlin, eurasian whimbrel, and bar-tailed godwit. the lincolnshire wildlife trust have a reserve there, which is next to rspb frampton marsh, a reserve managed by the royal society for the protection of birds.