Seasonal distribution and timing of migration of Cormorants Phalacrocorax carbo sinensis breeding in Denmark

Abstract

The recent expansion of the Cormorant Phalacrocorax carbo population in Europe has led to management conflict throughout Europe, increasing the relevance of describing the migration pattern of each country's breeding population. We use 2279 recoveries and 16 769 resightings of 4735 colour-ringed individuals to describe dispersal and timing of movements of Danish Cormorants. Most Cormorants dispersed from the colonies to coastal areas and freshwater lakes in Denmark, Sweden and northern Germany in July. Southward movements took place throughout July to December. Major departure from the post-breeding areas occurred from August to mid-October, with many birds staging at Dutch and Alpine lakes between September and October, and with arrival in the Mediterranean mainly from October to November. Spring migration was fast, occurring from mid-February to March. First-year birds migrated south faster and reached the wintering areas sooner than adults, but left these later and moved north more slowly than adults. Wintering occurred from Portugal in the west to Greece in the east, and from Denmark in the north to North Africa in the south. The majority of Cormorants spent the winter in Mediterranean France, Italy, Yugoslavia, Albania, Algeria and in particular in Tunisia. Adult males stayed closer to the breeding areas in winter than females, and adults tended to winter further north than first-year birds. Sex differences in body size and advantages of arriving early at the breeding sites may explain why males wintered further north than females.