The cormorants of Lake Ladoga in the early 20th century: Arctic invaders or continental colonists?

Authors

• Henry Pihlström Physiology and Neuroscience, Department of Biosciences, University of Helsinki

Abstract

There are two native subspecies of the great cormorant Phalacrocorax carbo in Europe: the mainly coastal nominate subspecies carbo, and the mainly continental subspecies sinensis. The population of the latter, in particular, has increased significantly in recent decades. Old literature records suggest that cormorants of some kind were breeding at the largest freshwater lake in Europe, Lake Ladoga, in the early part of the 20th century. A couple of specimens from this population were allegedly also collected; however, the current whereabouts of these specimens appear to be unknown. Recent studies have shown that both cormorant subspecies are ecologically fairly flexible and, therefore, breeding at a freshwater locality cannot by itself be regarded as evidence that they belonged to the continental subspecies sinensis. Thus, it is not possible to ascertain with certainty to which subspecies Lake Ladoga’s cormorants belonged.