Attributes / relations provided by
♦ 1del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.).
Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.
♦ 2Feeding ecology of sympatric European shags Phalacrocorax aristotelis
and great cormorants P. carbo in Iceland, Kristjan Lilliendahl, Jon Solmundsson, Marine Biology (2006) 149: 979–990