268 



F. SALOMONSEN 



The Danish Monarchy consists of three 

 parts far removed from each other, scattered 

 in the North Atlantic namely Denmark 

 proper, the Faroe Islands, and Greenland. 

 They differ so much from each other in cli- 

 mate and in bird life that they must be treated 

 separately in this paper. The Faroes possess a 

 provincial government and also a sort of home 

 rule. Greenland also has a provincial govern- 

 ment, but all statutory provisions, including 

 acts concerning hunting or wildlife protection, 

 must be passed by Danish authorities, usually 

 by the Ministry of Greenland. 



Insofar as seabirds are concerned, it is im- 

 portant that Greenland is an arctic country, 

 whereas the Faroes and Denmark are boreal. 

 In both Greenland and the Faroes the breed- 

 ing birds are most significant, from an eco- 

 logical point of view, whereas in Denmark the 

 passage migrants and winter visitors are far 

 more important. 



There are other differences as well. In 

 Greenland and the Faroes the seabirds mostly 

 breed in colonies on high and steep cliffs, and 

 the structure of these breeding places is not 

 disturbed .by man. In Denmark, on the other 

 hand, the seabirds usually breed on glacial de- 

 posits, now forming meadows, low islets, salt 

 marshes, etc., and these habitats have unfor- 

 tunately been largely changed in the last hun- 

 dred years by draining and reclamation. This 

 practice has taken place in Denmark on a 

 much larger scale than in most other coun- 

 tries and has, therefore, to a high degree 

 diminished the life conditions of seabirds. 



Seabirds in Denmark 



Denmark is situated on the continental 

 shelf of western Europe; all seas surrounding 

 the country are shallow (less than 100 m 

 deep), apart from the Skagerrak, north of Jut- 

 land, which is much deeper. The shallow 

 depth, combined with the rapid flow of water 

 between the Baltic and the North seas causes 

 much upwelling, which forms excellent life 

 conditions for plants and animals. It is well 

 known that the fishery in Danish waters, es- 

 pecially in the North Sea, is very rich. This 

 richness of the seas provides suitable condi- 

 tions for a high diversity of seabirds and eco- 

 logical types. 



Seabirds regularly breeding in Denmark in- 

 clude five species of terns (common tern, 

 Sterna hirundo; arctic tern, S. paradisaea; 

 least tern, S. albifrons; Sandwich tern, 

 S. sandvicensis; and gull-billed tern, Gelo- 

 chelidon nilota); seven species of gulls (black- 

 headed gull, Larus ridibundus; herring gull, 

 L. argentatus; lesser black -backed gull, L. fi+s- 

 cus; great black-backed gull, L. marinus; mew 

 gull, L. canus; little gull, L. minutus; and 

 black-legged kittiwake, Rissa tridactyla); four 

 species of geese, swans, and ducks (mute 

 swan, Cygnus olor; greylag goose, Anser 

 anser; common eider, Somateria mollissima; 

 common merganser, Mergus merganser; and 

 red-breasted merganser, M. serrator); three 

 species of auks (black guillemot, Cepphus 

 grylle; common murre, Una aalge; and razor- 

 bill, Alca torda); and one species of cormorant 

 (great cormorant, Phalacrocorax carbo). 

 Shorebirds have not been included in this re- 

 view. Some of the species mentioned are 

 partly freshwater birds for example, the 

 black-headed gull, little gull, mute swan, grey- 

 lag goose, and the two species of mergansers. 

 The gull-billed tern forages in terrestrial habi- 

 tats, but nests along the coast with the other 

 seabirds. It is often difficult, therefore, to 

 make a clear-cut distinction between seabirds 

 and freshwater birds. 



Among the auks, the black guillemot 

 breeds in the Cattegat area in the huge heaps 

 of boulders on small raised islets, or in holes 

 (mostly formed by starlings, Sturnus vul- 

 garis) on steep clayey slopes or promontories. 

 The common murre and razorbill are re- 

 stricted to the islet Graesholm in the Chris- 

 tiansri Archipelago, about 24 km east of Born- 

 holm Island in the Baltic, where they breed on 

 small cliffs of Precambrian granite rock. 



The estimated number of seabirds of dif- 

 ferent species that breed in Denmark is shown 

 in Table 1. Species like the mergansers, mute 

 swan, and greylag goose, which breed partly 

 or mostly in freshwater localities, are not in- 

 cluded. Overall, the number of breeding sea- 

 birds is slowly declining, probably due to 

 many factors which are discussed below. 

 There are two exceptions, however, to this 

 general decrease the herring gull (and to a 

 lesser degree the other big gull species) and 

 common eider. Both species have increased 

 during the last 50 years. Since they breed in 



