Wintering Great Cormorant roost counting

The simultaneous count of Great Cormorant roosts in mid-January provides the most accurate estimation of the total number of the wintering individuals and a precise description of the wintering range of the species.
Coordinated roost census allows to count the entire population, while day counts systematically underestimate it (as birds are scattered).

This census is conducted in some years, in the same way in many countries in order to establish results across the range of the species.
For more information on this monitoring, download the manual to count Great Cormorant roosts.

Photo credits: ©Thomas Galewski
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