Bregnballe, T. & Nitschke, M. 2017. Danmarks ynglebestand af skarver i 2017. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 40 s. - Teknisk rapport fra DCE - Nationalt Center for Miljø og Energi nr. 103. http://dce2.au.dk/pub/TR103.pdf
This report presents the results of the annual count of all apparently occupied Great Cormorant nests throughout Denmark. In 2017, a total of 33,171 nests were registered, which is 1,489 nests more than in 2016, corresponding to an increase of 4.7%. In Denmark as a whole, the Cormorant breeding population maintained stable numbers at around 39,000 pairs during 1993-2006, followed by a decline to around 26,400 pairs in 2010-2013.
In three out of seven regions, there were minor, modest and fair decreases in breeding numbers from 2016 to 2017, whereas numbers increased moderately in two regions and substantially in another two regions. Generally, the increase occurred in all southern regions and in the westernmost region. The largest increase was found in the westernmost region, including the fjords of western Jutland where the vast majority of breeders are found in Ringkøbing Fjord. Numbers in this region increased by 42%.
The total number of breeding colonies in Denmark decreased from 83 in 2016 to 79 in 2017. The trend in earlier years of a gradual decrease in the size of the largest colonies did not continue in 2017. On the contrary, the number of colonies with more than 1,000 breeding pairs increased from 10 in 2016 to 11 in 2017. The largest colony (1,995 nests) was located in Stavns Fjord on the island of Samsø.
The Danish Nature Agency, Ministry of the Environment, implemented management measures to reduce breeding success in 12 colonies in 2017 and gave permission to private landowners to undertake management in another five colonies. In 2017, a total of 4,855 nests were subjected to management. The eggs in 2,888 nests were sprayed with vegetable oil and the remaining nests were managed by removal. More nests were subjected to management in 2016 and 2017 than in 2010-2015.
