Attributes / relations provided by
♦ ¹Predation of the shelduck Tadorna tadorna on the mud snail Hydrobia ulvae, N. R. Anders, T. Churchyard, J. G. Hiddink, Aquat Ecol 2009, vol. 43, no. 4, pp. 1193-1199
♦ ²del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.