Estuarine pollution as a probable cause of increase of estuarine birds

A long-term increase of estuarine birds does not always appear to be a good indication of the improvement of the environmental quality of an estuary. This paper shows that an incontestable ecological deterioration in a part of the Scheldt estuary has led probably to a greater food supply for intertidal birds. They respond to this phenomenon by visiting the area in increasing numbers, and the period of migration of birds on other feeding grounds nearby differs from theirs.