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F. SALOMONSEN 



breaks of botulism in recent years, procedures 

 to improve conditions are now being 

 developed. 



Other Threats to Seabirds 



The most dangerous threats to seabirds are 

 those discussed above. Authorities are aware 

 of these dangers and attempts are being made 

 to improve conditions. Some results have 

 been achieved in the combat against oil pollu- 

 tion, and the control of shooting is reaching 

 an acceptable level. Game management agen- 

 cies in Denmark and other Scandinavian 

 countries (Norway, Sweden, and Finland) are 

 cooperating on the request of the parliamen- 

 tary body of the Nordic Council. If game 

 biologists in these countries could agree on 

 proposed changes in the game acts, owing to 

 the marked decline of a number of bird 

 species, the parliamentary basis for such a 

 legal step would be absolutely certain. 



However, it must be admitted that the im- 

 pact of man on the environment is enormous, 

 especially in a country like Denmark, which 

 possesses no raw materials, and where agri- 

 culture has transformed the whole country. In 

 such a country, the birds have to "face the 

 music," and by this sharing of resources with 

 man, they will inevitably decrease in number. 

 It is the responsibility of biologists and politi- 

 cians, without emotional biases, to find the 

 balance between the requirements of the two 

 spheres of interest. 



Many other dangers that threaten seabirds, 

 some of which are unrelated to human activi- 

 ties, are listed here. 



Land reclamation. Reclamation of land 

 has reduced extensive areas of shallow water, 

 lagoons, marsh land, etc., from seabirds for 

 foraging or breeding places. Draining and dik- 

 ing of coastlands, estuaries, and saltings have 

 had the same effect. This activity is now al- 

 most stopped, as these projects are no longer 

 subsidized by the government. 



Egg-collecting. According to the present 

 game act, collecting gull eggs is permitted 

 until 24 May. This creates much disturbance 

 on the breeding grounds, and eggs of terns 

 and shorebirds are also taken. This practice 

 should be halted. The "Bird Island Group" of 

 the Danish Ornithological Society, in a sym- 

 posium in 1972, prepared some rules for the 



protection of seabirds, among which is a pro- 

 posal to stop egg-collecting. 



Common property. The Nature Conser- 

 vancy Act regards all land not fenced in, even 

 small uninhabited islets, as common property. 

 People have free access to such areas with the 

 result that seabirds breeding in colonies, or 

 separately on islands, are disturbed by visi- 

 tors arriving by boat. At the same time, noisy 

 motorboats, bathing parties, or camping visi- 

 tors frighten the birds, making successful 

 breeding almost impossible. Even ornitholo- 

 gists, bird-banding teams, and bird photog- 

 raphers add to the destruction. The "Bird Is- 

 land Group" of the Danish Ornithological 

 Society has proposed a general prohibition 

 against visitors on important bird islands 

 from 1 March to 15 July to protect the breed- 

 ing seabirds. 



Destruction by predators. Fox, ermine, 

 and stone-marten do not play an essential 

 role. Rats are more important, even on small 

 islands, and have caused destruction of tern 

 and gull colonies. Rat numbers do not decline 

 until a severe winter with much ice occurs, or 

 until high tide kills them all. Large gulls also 

 cause a great deal of destruction, but crows 

 and magpies are unimportant as predators in 

 seabird colonies. Numbers of nonbreeding 

 mute swans or greylag geese may sometimes 

 be a nuisance, trampling eggs and nestlings in 

 seabird colonies. 



Forestry practices. The prevailing prac- 

 tice of the forestry industry in Denmark of 

 not preserving old trees with holes has con- 

 siderably diminished the breeding habitat of 

 hole-nesting species like the common mer- 

 ganser. Artificial nest-boxes have now been 

 established in several areas. 



Sea conditions. During high water, or 

 rough sea, salt water may flood colonies of 

 breeding seabirds nesting on low islets, often 

 reducing the production of young. 



Aircraft disturbance. Disturbances are 

 also caused by noise from jet aircraft flying 

 low, especially in military training areas 

 where air traffic may be heavy. 



Commercial fisheries. Modern commer- 

 cial fisheries are depleting so-called indus- 

 trially important fish stocks such as sand eels 

 (Ammodytes), herrings, and other small fish 

 over large areas of the sea for the production 



