Fig. 4From: An invasive alien bivalve apparently provides a novel food source for moulting and wintering benthic feeding sea ducksDistribution of the common scoter Melanitta nigra in the German North Sea during the wintering season given as individuals km−2. The map shows data from the months December to February in the years 2015–2017. To calculate densities, the number of birds was summed for all surveysBack to article page