Chapter XIX: Part 5: , pages 225-247 in Soviet fisheries investigations in the (4)

Only three marine species are not afforded full protection under the Wildlife Act: two, the black-backed or Dominican gull _(Larus dominicanus)_ and the black shag _(Phalacrocorax carbo)_, are totally unprotected--the first because of its predation on some rare shorebirds during the breeding season and for its attacks on sheep and lambs at a similar time, and the second because of its depredations (seldom serious) on the introduced trout and salmon, mainly in fresh waters--the third species, the southern skua _(Stercorarius skua lonnbergi)_, may be destroyed only when it is actually attacking sheep or lambs, an occasional event confined to the Chatham Islands. Destruction of these three common species is not encouraged by the Wildlife Service except when black-backed gulls become too active among colonies of, say, the fairy tern _(Sterna nereis)_, which is very rare in New Zealand but not elsewhere in its range. Otherwise, control of the species is left in the hands of those most affected by their depredations but whose judgment is usually reasonable.

Marine birds, therefore, are generally satisfactorily protected by law or managed for conservation in New Zealand--especially when one considers the remarkable changes that have occurred in the New Zealand archipelago over the last 200 years. Although the situation could be better, it would certainly have been worse if the Wildlife Service (and other conservation organizations) had not been untiring in keeping the general public and the legislature aware of the issues at stake and seen to it that as much as possible of the necessary conservation work was done--and done before it was too late.

Acknowledgments

I thank my Wildlife Service colleagues, B. D. Bell, M. J. Imber, D. V. Merton, and C. J. R. Robertson, for valuable comments and advice on the preparation of this paper.

References

Atkinson, I. A. E., and B. D. Bell. 1973. Offshore and outlying
islands. Pages 372-392 _in_ G. R. Williams, ed. The natural
history of New Zealand. A. H. & A. W. Reed, Wellington.

Bourne, W. R. P. 1967. Subfossil petrel bones from the Chatham
Islands. Ibis 109:1-7.

Kinsky, F. C. 1970. Annotated checklist of the birds of New
Zealand. A. H. & A. W. Reed, Wellington.

Gibb, J. A., and J. E. C. Flux. 1973. Mammals. Pages 334-371 _in_
G. R. Williams, ed. The natural history of New Zealand. A. H. &
A. W. Reed, Wellington.

Williams, G. R. 1973. Birds. Pages 304-333 _in_ G. R. Williams,
ed. The natural history of New Zealand. A. H. & A. W. Reed,
Wellington.

Williams, G. R. 1977. Marooning--a technique for saving threatened
species from extinction. Int. Zoo Yearb. 17:102-106.

Marine Birds in the Danish Monarchy and Their Conservation

by

Finn Salomonsen

Chief Curator of Birds The Zoological Museum University of Copenhagen Copenhagen, Denmark

Abstract

Most species of seabirds that regularly breed
in Denmark are declining, for a variety of
reasons: shooting; oil pollution; toxic
chemicals; reclamation of land; collecting
of eggs; disturbance at breeding sites
by visitors, motorboats, camping, etc.;
destruction by predators; and others. On the
other hand, the numbers of certain other
species are increasing as a result of climatic
changes (six species), protection (three
species), and increase in food supply (three
species of gulls). In addition to breeding
birds, a total of about 3 million birds occur
in Danish waters as passage migrants or winter
visitors. More than half of the European winter
populations of a number of marine waterfowl
species winter in Denmark. Large numbers of
seabirds spend the summer in Danish waters,
including several hundred thousand immature
gulls and just as many molting waterfowl.

The seabird fauna of the Faroe Islands is
very rich, the immense number of birds
being attracted by the local abundance
of macroplankton and fish. The seabirds
are harvested by man, formerly by fowling
(capturing and shooting), now primarily by
shooting. Until about 1910, more than 400,000
birds were taken annually by fowling. The
Faroese game act is now very restrictive, and
most seabird populations appear to be almost
stable. However, a census in 1972 indicated
that common murres _(Uria aalge)_ have declined
by about 20% to a population of about 600,000.
Shooting and snaring appear to be the primary
causes of the decline; oil pollution and toxic
chemicals do not seem to be contributing to the
population decrease.

In Greenland seabirds provide an important
source of human food; however, because of the
increase in human population and in the use
of guns and speedboats for hunting, and the
absence of a game act, serious overshooting
of seabirds is taking place. A new game act
passed in 1977 should largely alleviate
this overharvest. Oil pollution and toxic
chemicals do not yet play an important part
in influencing the number of seabirds, though
offshore oil drilling is being initiated in
West Greenland. A recently established gigantic
national park, covering 200,000 km² of ice-free
land, is the largest nature reserve in the
world.

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 climate 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 government, 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 important that Greenland is an arctic country, whereas the Faroes and Denmark are boreal. In both Greenland and the Faroes the breeding birds are most significant, from an ecological 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 deposits, now forming meadows, low islets, salt marshes, etc., and these habitats have unfortunately been largely changed in the last hundred years by draining and reclamation. This practice has taken place in Denmark on a much larger scale than in most other countries 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 Jutland, 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, especially in the North Sea, is very rich. This richness of the seas provides suitable conditions for a high diversity of seabirds and ecological types.

Seabirds regularly breeding in Denmark include five species of terns (common tern, _Sterna hirundo_; arctic tern, _S. paradisaea_; least tern, _S. albifrons_; Sandwich tern, _S. sandvicensis_; and gull-billed tern, _Gelochelidon nilota_); seven species of gulls (black-headed gull, _Larus ridibundus_; herring gull, _L. argentatus_; lesser black-backed gull, _L. fuscus_; 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, _Uria aalge_; and razorbill, _Alca torda_); and one species of cormorant (great cormorant, _Phalacrocorax carbo_). Shorebirds have not been included in this review. Some of the species mentioned are partly freshwater birds--for example, the black-headed gull, little gull, mute swan, greylag goose, and the two species of mergansers. The gull-billed tern forages in terrestrial habitats, 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 vulgaris_) on steep clayey slopes or promontories. The common murre and razorbill are restricted to the islet Graesholm in the Christiansø Archipelago, about 24 km east of Bornholm Island in the Baltic, where they breed on small cliffs of Precambrian granite rock.

The estimated number of seabirds of different 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 included. Overall, the number of breeding seabirds 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 the same habitat, usually mixed together, the eider is probably dependent on herring gulls for protection against predators. When the ducklings are fledged, the herring gull acts as a successful predator itself, but the eider nevertheless maintains a close association with herring gulls.

Table 1. _Estimated average number of breeding pairs of seabirds
in Denmark, based on a census in 1970-72._ (Data for terns from
Mardal 1974, and for other species from Sten Asbirk and N. O.
Preuss, personal communications.)

Number of
breeding
Species pairs

_Sterna paradisaea_ 5,750
_S. hirundo_ 900
_S. sandvicensis_ 4,000
_S. albifrons_ 600
_Gelochelidon nilotica_ 105
_Larus marinus_ 300
_L. argentatus_ 60,000
_L. fuscus_ 2,000
_L. canus_ 28,500
_L. ridibundus_ 135,000
_L. minutus_ 25
_Rissa tridactyla_ 125
_Phalacrocorax carbo_ 600
_Somateria mollissima_ 3,800
_Cepphus grylle_ 325
_Alca torda_ 400
_Uria aalge_ 1,100
Total 243,530

More than 90% of the herring gull population breeds on small islands, and a large proportion occurs in a few large colonies. It never breeds in freshwater localities, but is exclusively found as a breeding bird in coastal habitats. The population has particularly increased in the last 5 decades, some colonies reaching their maximum size in the 1960's. Others are still expanding and occupying new breeding grounds. Today the largest colonies are found on the following islands: Saltholm, 20,000-40,000 pairs; Christiansø 9,000 pairs; Hirsholmene, 2,500 pairs; Jordsand, 1,800 pairs; Samsø, 2,000 pairs; Hjelm, 1,500 pairs; and the archipelago south of Funen, a total of 3,500 pairs in several colonies.

Attempts have been made to reduce the breeding population of herring gulls at Hirsholmene and Christiansø sanctuaries (in 1973 and 1974, respectively), to improve conditions for other nesting seabirds. In 1969 the Bird Strike Committee of the Royal Danish Airforce also initiated a program to reduce the number of herring gulls breeding on Saltholm Island, which is near the Kastrup airport in Copenhagen. Nests were sprayed with a formaldehyde oil dye, which resulted in a 33% reduction in population. In Christiansø and Hirsholmene, where the adult breeding birds were poisoned, the effect is not yet known.

The total number of seabirds occurring in the Danish waters as passage migrants and winter visitors is substantially larger than the breeding population, because Denmark is situated on a very important fall migration route for seabirds from Scandinavia, the Baltic countries, northern Russia, and northwestern Siberia. Furthermore, the shallow waters of the Danish seas (less than 10 m deep) that occupy extensive regions bordering the coasts are important feeding grounds for diving ducks. Birds frequenting the seas outside the breeding season include hundreds of thousands, or probably millions, of gulls; numerous ducks (especially diving ducks); swans and brants, _Branta bernicla_; jaegers, _Stercorarius_ spp. (four species); loons, _Gavia_ spp. (four species); grebes, _Podiceps_ spp. (four or five species); gannet, _Morus bassanus_; great cormorant; northern fulmar, _Fulmarus glacialis_; common murre; razorbill; and other species of alcids. To these should be added a number of species of various seabirds, especially gulls, tubenoses, phalaropes, and others which appear as casual or accidental visitors and which are not further mentioned in this paper.

Table 2. _Total numbers of ducks, swans, and coots recorded in
Denmark during a winter census in January 1973 (based on ground
counts and aerial surveys), compared with estimated flyway
populations wintering in western Europe and annual bird harvest
in Denmark (after Joensen 1974:23, 155, 168)._

Estimated winter Average
Census, populations of the annual bag
Species January 1973 Western Europe Flyway in Denmark

_Anas platyrhynchos_ 127,000 1,550,000 380,000
_A. crecca_ 500 260,000 76,000
_A. querquedula_ 11 [67] [68]
_A. acuta_ 100 70,000 13,000
_A. strepera_ 5 [67] [69]
_A. penelope_ 3,000 485,000 44,000
_A. clypeata_ 17 63,000 9,000
_Tadorna tadorna_ 13,000 105,000 [69]
_Aythya ferina_ 7,100 235,000 5,000
_A. fuligula_ 94,700 530,000 35,000
_A. marila_ 80,900 145,000 8,000
_Clangula hyemalis_ 11,000 [67] 11,000
_Melanitta nigra_ 148,100 [67] 18,000
_M. fusca_ 6,700 [67] 9,000
_Somateria mollissima_ 450,800 [67] 136,000
_Bucephala clangula_ 67,000 142,000 25,000
_Mergus serrator_ 11,700 40,000 8,000
_M. merganser_ 23,200 75,000 6,000
_M. albellus_ 206 5,000 [69]
_Cygnus olor_ 48,900 120,000 [69]
_C. cygnus_ 5,700 17,000 [69]
_C. bewickii_ 1,113 6,000 [69]
_Fulica atra_ 142,500 [67] 70,000
Totals 1,243,252 3,848,000 853,000

A comprehensive investigation of the nonbreeding waterfowl in Danish waters was recently undertaken by the Game Biology Station Kalø (Joensen 1974). Aerial surveys of marine ducks indicate that a large percentage of the ducks that winter in European waters do so in the shallow areas of the Danish seas. A census in January 1973 indicated a total of more than 1.2 million birds (Table 2). In a number of other countrywide surveys, undertaken in all winters since 1967, usually 1.0-1.5 million birds have been recorded. Since such censuses usually give minimum numbers, and certain species-especially marine ducks--generally go unrecorded, the normal winter population (November to February) of ducks, swans, and coots in Danish waters can scarcely be less than 2 million birds (Joensen 1974:156). In Table 2, bird numbers in Denmark are compared with the estimated winter populations in western Europe, based on the investigation of Atkinson-Willes (1972). When all the winter censuses in Denmark are compared with those for Europe, as was done by Joensen (1974:156), it is evident that Danish waters support about half of all greater scaup _(Aythya marila)_, common goldeneye _(Bucephala clangula)_, red-breasted merganser, mute, whooper _(Cygnus cygnus)_, and tundra swans _(C. bewickii)_ wintering in Europe; about one-third of the population of tufted duck _(Aythya fuligula)_ and common merganser; and probably also one-third of the population of common eider and coot _(Fulica atra)_.

The wintering population of common eider is very large. According to banding records it makes up the greater part of Baltic breeding birds; however, it is not possible to calculate its percentage contribution to the total European winter population since its size is unknown in most European countries. Although most of the surface-feeding ducks disappear from Denmark waters in winter, extremely large numbers occur there during the fall migration period. For example, it has been estimated that for species like common teal _(Anas crecca)_ and wigeon _(A. penelope)_ about one-third of the West European Flyway population passes Denmark in the fall. Possibly some of the surface-feeding ducks listed in Table 2 for January 1973 were recorded in fresh water and not from the seas, but at the time the census was taken most freshwater lakes were frozen and, therefore, unavailable for water birds.

These breeding seabirds and the off-season visitors do not constitute the total population in Danish waters. Large numbers also occur in summer as nonbreeding birds; most are in two categories: (1) several hundred thousand pre-adult (up to 4-5 years of age) gulls (mostly great black-backed, herring, and lesser black-backed gulls), which feed inshore or at the coast, and (2) large concentrations of waterfowl that carry out a molt migration in Danish waters, particularly in shallow areas. Black scoter _(Melanitta nigra)_, velvet scoter _(M. fusca)_, common eider, and whooper swan are especially numerous, totaling hundreds of thousands of individuals, and probably constituting the majority of the European molting populations of these species. Less numerous, but still totaling thousands of molting birds, are sheld-duck _(Tadorna tadorna)_, common goldeneye, red-breasted merganser, and possibly some other diving ducks. About 3,000 surface-feeding ducks of various species, most of which undoubtedly are local breeding birds undergo wing molt in Danish waters. Comprehensive descriptions of the molt migration, particularly in Denmark, were published by Salomonsen (1968) and Joensen (1973_a_, 1974).

It may then be concluded that very large numbers of seabirds are found in Danish waters in all periods of the year; most feed in the inshore zone and some offshore, but none in the pelagic zone.

_Increase of Seabirds_

Seabirds are affected by several factors related to human activities, most of which pose a threat to them and will eventually reduce their numbers. Some factors, however, tend to increase bird numbers, like climatic changes which, as reported by Salomonsen (1963), have given rise to the immigration to Denmark of great cormorant (in 1938); eared grebe, _Podiceps nigricollis_ (about 1870); red-crested pochard, _Netta rufina_ (1940); common pochard, _Aythya ferina_ (about 1860); tufted duck (about 1900); and common murre (1929). They all still breed in Denmark, having more or less increased in number.

Another reason for increases of certain species is legal protection. Among protected seabirds are the sheld-duck, which has been completely protected since 1931, and particularly the mute swan, of which only 2 or 3 pairs were breeding in Denmark when the species was completely protected in 1926. Since then, mute swans have increased enormously, reaching at least 2,740 pairs in 1966 (Bloch 1971:43), of which large numbers were breeding colonially on small islets of boulders or on sand reefs off the coast (Bloch 1970:152). The gannet has also increased considerably as a fall visitor since about 1945, apparently due to protection in England and other countries.

Finally, some gull populations have increased in size because of an increase in the food supply, consisting especially of wastes from commercial fisheries and garbage dumps. In Denmark, this unnatural food source has caused an enormous increase since about 1925 in herring gulls (from less than 500 pairs to 60,000 pairs), lesser black-backed gulls (all three subspecies, _fuscus_, _intermedius_, and _graelsii_ have immigrated to Denmark), and great black-backed gulls (immigrated to Denmark in 1930). Improved waste disposal practices in recent years have not yet offset the rate of growth of these gull populations. The increase of common eiders, which also started in about 1925, is probably related to the increases in the larger gulls.

_Decrease of Seabirds_

A variety of factors tend to reduce the numbers of seabirds. The most important ones are outlined below, with comments on what has been done or what is expected to be done to reduce the impact of these activities on seabirds and protect this endangered resource.

Shooting of Seabirds

The shooting of seabirds in Denmark is considerable, because the seabirds are extraordinarily numerous, and the number of sportsmen is very large, amounting to about 135,000 (a larger number per capita than in any other country).

The Danish game statistics are excellent--well known to be much more accurate than in most other countries (see Salomonsen 1954; Strandgaard 1964). According to Danish bag records, almost one million ducks, geese, and coots (Joensen 1974:31) and about 100,000-200,000 gulls (Salomonsen 1954:125) are shot each year. The average annual bag of each species of wildfowl is given in Table 2 and the open season for each species of seabirds in Table 3. The open season for dabbling ducks is long, extending from 16 August to 31 December, which means that local birds are persecuted almost as soon as birds-of-the-year are able to fly. This has resulted in a dabbling duck breeding population that is much smaller than what the available food supply could support, and in the large-scale development of artificial rearing of mallards for later shooting. A 5-month hunting season on specialized birds like loons, grebes, and various auks is not good management practice and should be carefully reviewed.

Four other important facts about the shooting of seabirds in Denmark merit inclusion here: (1) there is no bag-limit for any species; (2) in general, all marine areas within territorial limits are open to all Danish sportsmen, and the admission is free; (3) motorboats with a maximum speed of 10 knots are allowed for shooting in the period 1 October-30 April; and (4) the shooting of seabirds is permissible from 1.5 h before sunrise to 1.5 h (in December 1 h) after sunset, whereas for most other birds shooting is prohibited between sunset and sunrise.

Shooting is a national tradition in Denmark, and the large number of sportsmen has considerable political power. Too much influence is given to the representatives of the hunters' organizations, which have the decisive force in game committees dealing with protective measures. It is difficult, therefore, to change the existing system.

Table 3. _Open hunting seasons for seabirds in Denmark, according
to the Game Act of 1967. Species not given in the table are fully
protected._

Hunting period and species

1 August-31 December
_Anser anser_
_A. fabalis_
_A. brachyrhynchus_
_A. albifrons_
_Branta bernicla_[70]
_B. canadensis_

1 August-30 April
_Phalacrocorax carbo_

16 August-31 December
_Anas platyrhynchos_
_A. crecca_
_A. querquedula_
_A. acuta_
_A. penelope_
_A. clypeata_

16 August-29 February
_Aythya ferina_
_Fulica atra_
_Larus ridibundus_
_L. canus_

16 August-30 April
_L. fuscus_
_L. argentatus_
_L. marinus_

1 October-29 February
_Aythya fuligula_
_A. marila_
_Clangula hyemalis_
_Melanitta nigra_
_M. fusca_
_Somateria mollissima_
_Bucephala clangula_
_Mergus serrator_
_M. merganser_
_Gavia stellata_
_G. arctica_
_G. immer_
_Podiceps cristatus_
_Uria aalge_
_U. lomvia_
_Alca torda_

Shooting of seabirds, especially various waterfowl, is popular and intensive. The number of ducks taken by Danish sportsmen is probably in the order of 10-15% of the total kill on the West European Flyway (Joensen 1974:171). Excessive duck shooting can, in some cases, be controlled by banding in the breeding areas; the ensuing results then give rise to strong protests from the Scandinavian countries against the extensive persecution. As stated above, Denmark has (in relation to its size) the largest number of sportsmen of any nation in the world and the most intensive shooting. The number of sportsmen shooting ducks and shorebirds per 100 km² is 278 in Denmark, 28 in Sweden, 37 in Finland, 10 in Poland, 83 in Holland, 164 in Britain, and 129 in Western Germany; the number of ducks shot per 100 km² is 1,856 in Denmark, 39 in Sweden, 68 in Finland, and 129 in Western Germany (Nowak 1973). This shooting is undoubtedly of importance to dabbling duck populations, which are popular as shooting objects everywhere in Europe.

Insofar as marine ducks are concerned, it can be seen in Table 2 that appreciable numbers are shot in Denmark. The same is true for other Scandinavian countries, whereas shooting on the high seas is rather modest in most other European countries. The Danish bag undoubtedly makes up a significant proportion of the total number of marine ducks killed each year, but when the total number of ducks in European waters is considered, the shooting pressure in Denmark appears to be of only minor importance. However, the shooting, particularly when undertaken from motorboats, is so noisy and makes such a disturbance over large areas that the time for seabirds to rest and forage is significantly reduced. It must also be noted that the number of pleasure craft is steadily increasing in the present period of prosperity, and that increasing numbers of sportsmen will probably make use of the free shooting in territorial waters, since it is becoming more and more expensive to lease hunting areas.

To restrict seabird shooting, the Danish Ornithological Society has recently (1975) submitted a proposal to the Danish Government, of which the following points are relevant:

• The open season for dabbling ducks and geese should begin 15 September except for pintail _(Anas strepera)_, shoveler _(A. clypeata)_, wigeon, and pochard--species which should not be hunted until 1 October;

• the open season for all diving ducks, as well as for coot, should end 31 December;

• the open season for the great cormorant should be restricted to the period between 15 September and 31 October;

• murres, razorbill, great-crested grebe _(Podiceps cristatus)_, and all species of loon should be fully protected;

• it should be prohibited to shoot from motorboats less than 1 km from the shoreline, as well as in certain narrow sounds and fjords;

• it should be prohibited to shoot from shooting-punts less than 100 m from the shoreline;

• it should be prohibited to sell waterfowl and shorebirds shot, except for eider ducks and mallards _(Anas platyrhynchos)_; and

• no shooting should be allowed between sunset and one hour before sunrise.

Oil Pollution

Oil pollution incidents constitute one of the greatest dangers to seabird populations in Danish waters. The enormous masses of seabirds present in these waters throughout the year, combined with the fact that Danish waters contain some of the heaviest shipping traffic in the world would give rise to anxiety for oil disasters. The majority of all tanker traffic from the Atlantic and the North Sea to the Baltic passes through the Cattegat and the narrow straits of the Sound, the Great Belt, and the Little Belt, to supply a population of about 100 million people. Up to 100,000 ships pass through these waters each year, half through the Sound.

There have been severe oil pollution disasters every year since about 1935, accompanied by enormous mortalities of seabirds, particularly marine ducks. The Danish Game Biology Station, which has studied these disasters (Joensen 1972_a_, 1972_b_, 1973_b_), has noticed that the number of seabirds involved has increased in recent years, in spite of increased control by Danish authorities.

Unfortunately, it appears that small amounts of oil in the sea, originating from cleaning the tanks of vessels, or from the release of a few tons of oil, are enough to create mass mortality of seabirds when large concentrations of birds are present in the vicinity. Such incidents have passed unnoticed in spite of control measures. In no case has the source of the pollution been traced (Joensen 1972_b_:27). There has not yet been a real "oil disaster" in the Danish waters similar to the _Torrey Canyon_ catastrophe. If such a disaster takes place, the destruction of seabirds will be enormous and immeasurable.

Table 4. _Species composition of 8,304 birds killed by oil and
examined in connection with five pollution disasters in the
Cattegat, 1969-71._ (After Joensen 1972:12.)

Oil incident no.

Species 1 2 3 4 5 Totals

_Gavia stellata_ 1 9 1 4 15
_G. arctica_ 2 2 4 8 16
_Gavia sp._ 4 1 5
_Podiceps grisegena_ 4 1 8 8 21
_P. cristatus_ 1 1
_Phalacrocorax carbo_ 20 20
_Anas platyrhynchos_ 2 2 4
_A. clypeata_ 2 2
_Aythya marila_ 6 2 8
_Clangula hyemalis_ 35 2 26 6 4 73
_Melanitta nigra_ 387 241 521 262 77 1,488
_M. fusca_ 197 33 417 223 119 989
_Somateria mollissima_ 1,683 1,081 947 1,713 19 5,443
_Bucephala clangula_ 3 3 13 9 28
_Mergus serrator_ 48 28 28 2 106
_Cygnus olor_ 10 17 1 28
_C. Cygnus_ 1 1
_Fulica atra_ 1 1 2 5 9
_Larus sp._ 13 13
_Alca torda_ 1 12 1 14
_Uria aalge_ 1 1
_Cepphus grylle_ 1 2 16 19

Total birds examined 2,380 1,362 1,996 2,324 242 8,304

Estimated minimum number
of birds killed 10,000 5,000 12,000 15,000 1,500 43,500

Percent of total birds contributed
by three species[71] 95.3 99.5 94.4 94.6 88.8 95.4

As a result of five of the major oil pollution incidents in the Cattegat from 1969-71, a total of 43,500 birds were killed, of which 8,304 were examined and enumerated (Table 4). Altogether, 21 or 22 species were involved, but 95% of all birds examined were diving ducks: common eider and black and velvet scoters. At present, it has not been possible to identify any decrease in the number of these ducks in Danish waters due to oil pollution. However, if these disasters continue, it can be expected that duck populations of northern Europe and the Baltic area will be severely reduced, and that an overall decline will take place from which the birds may not be able to recover.

A particularly disastrous year was 1972, when large numbers of ducks were killed as a result of rather small oil spills. A tanker disaster in March 1972 off the eastern coast of Jutland, in the northern Cattegat, and another in December 1972 in the Danish Waddensea, both took place in areas critical to major concentrations of sea ducks. A total of more than 60,000 birds were killed, of which about 95% consisted of the same three species of diving ducks mentioned above. These tragic events represent a further increase in the annual mortality of birds caused by oil, and there is reason to believe that a critical upper limit is rapidly being approached.

It appears, however, that the measures taken by pollution control and naval authorities have greatly improved in recent years. In January 1973, when a Polish merchant vessel collided with a Swedish tanker in the Sound, about 300 tons of heavy fuel oil were released into the sea. Several Danish and Swedish ships working in cooperation succeeded in dispersing the oil, and no serious effect on seabird populations took place (Joensen 1973_b_:118). It seems that the best way of cleaning up such oil disasters is through a mechanical removal of the oil, but this is a very expensive and difficult procedure.

Pollution by Toxic Chemicals

Chemical pollution is probably the most ominous threat to seabirds at present. Since all toxic chemicals used in agriculture ultimately end up in the sea, and many large factories release their industrial wastes directly into the sea, the effects of this pollution on marine organisms is attracting a growing interest. Many students have worked on these problems, and the results that concern birds were summarized by Bourne (1972:205). It is known that organochlorine residues have been found in seabirds in all the oceans of the world, including Antarctic waters and Arctic seas (Bogan and Bourne 1972:358). The chemicals most often found in birds are DDE (a metabolite of DDT) and PCB's (polychlorinated biphenyls), a mixture of related chemical compounds often originating from industrial wastes. In addition, some mercury will always be found, sometimes in increased concentrations. The present restrictions on the use of DDT and PCB in Denmark have not yet resulted in a corresponding decrease in the amount of these pesticides in birds.

It is well known that marine pollution reaches a peak in the Baltic. This high level of pollution is reflected in seabirds. For example, analyses have shown that eggs from the colony of common murres on Christiansø in the Baltic contain about 100 times as much DDE and 50 times as much PCB as eggs of murres from the Faroe Islands in the Atlantic Ocean (Dyck 1975).

A similar difference exists in the mercury content in birds examined in the two areas. Feathers of a large sample of black guillemots and murres from the Cattegat and the Baltic had higher mercury levels than those from the Faroe Islands and Greenland. It is interesting that this difference existed over a hundred years ago, as evidenced by the analysis of feathers in museum specimens. The Baltic populations of both species show very significant increases in the mercury content in 1965-70, as compared with the values earlier in this century. Since 1970 there has been a sharp decrease in mercury content, and in 1973 the level was almost as low as it was early in the century. These results indicate that the strict control of mercury discharges enforced in Sweden has resulted in a quick recovery of nearly normal conditions in the Baltic (Somer and Appelquist 1974). However, recent studies by Koeman et al. (1975:286) appear to show that mercury does not accumulate to the same extent in seabirds as it does in seals.

High concentrations of chlorinated hydrocarbon residues accumulate in carnivorous birds and upset the normal breeding behavior by making the eggshells too thin and fragile to survive (Peakall 1970:73; Mueller and Leach 1974:289). In Denmark, shells of herring gull eggs from the Baltic population were thinner, lighter, and more heavily contaminated with DDE and PCB than were shells of eggs from other colonies (Jørgensen and Kraul 1974:173). This further emphasizes the pollution of the Baltic Sea.

Massive mortalities of common murres, such as the one reported in the Irish Sea in the fall of 1969 which was apparently caused partly by malnutrition and PCB poisoning (Parslow and Jefferies 1973:87), are unknown in Danish waters.

It should be added that the pollution of seawater with cadmium, so very dangerous for man, has been high in recent years owing to the increased use of this element in industry, but no analysis of its importance for seabirds in Danish waters has yet been made.

It should also be mentioned that pollution of fresh water in lagoons or lakes near the sea can often cause serious declines in numbers of certain seabirds. This is well illustrated by recent events in the sanctuary Nakskov Indrefjord on the island of Lolland. This landlocked fjord once supported numerous breeding populations of ducks, grebes, and terns, but in recent years a number of species (e.g., eared grebe; common teal; garganey, _Anas querquedula_; pintail; and black tern, _Chlidonias nigra_) have failed to breed and practically all other species have declined in numbers. The main reason for these changes is a severe pollution from the admission of raw sewage from tributaries (Bloch et al. 1972). After several outbreaks 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 pollution, and the control of shooting is reaching an acceptable level. Game management agencies in Denmark and other Scandinavian countries (Norway, Sweden, and Finland) are cooperating on the request of the parliamentary 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 impact of man on the environment is enormous, especially in a country like Denmark, which possesses no raw materials, and where agriculture 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 politicians, 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 activities, 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 diking of coastlands, estuaries, and saltings have had the same effect. This activity is now almost 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 symposium in 1972, prepared some rules for the protection of seabirds, among which is a proposal to stop egg-collecting.

• Common property.--The Nature Conservancy 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 visitors arriving by boat. At the same time, noisy motorboats, bathing parties, or camping visitors frighten the birds, making successful breeding almost impossible. Even ornithologists, bird-banding teams, and bird photographers add to the destruction. The "Bird Island 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 breeding 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 practice of the forestry industry in Denmark of not preserving old trees with holes has considerably diminished the breeding habitat of hole-nesting species like the common merganser. 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 commercial fisheries are depleting so-called industrially important fish stocks such as sand eels _(Ammodytes)_, herrings, and other small fish over large areas of the sea for the production of fish meal. This fishing has undoubtedly been the main reason for the decline in the number of terns--especially sandwich terns which depend on these small fish species for food.

• Unknown factors at sea.--Large numbers of pelagic seabirds, particularly fulmars, kittiwakes, and gannets, are washed up on the western coast of Jutland in certain years (e.g., 1959, Joensen 1961:212). These birds died at sea, for unknown reasons, and apparently as a result of food shortages or oil pollution.

_Conservation_

The threats to seabirds mentioned above are all well known to conservationists, who are attempting to reduce the impact of these factors on seabirds where possible. Insofar as legal protection is concerned, it must be admitted that there are no marine sanctuaries in Denmark, although several discussions have taken place reviewing the possibility of establishing some in critical areas. There are, however, a number of sanctuaries on islands where seabirds breed. In the Sanctuary Act of 1936 these areas were called "Scientific Reserves" because they were the site of scientific investigations of bird life. All admission was forbidden, at least during the breeding season, and all shooting was prohibited, with few exceptions. These sanctuaries were administered by the government's Nature Conservancy.

The following Scientific Reserves are important for seabirds: Hirsholmene Islands (in Cattegat off Frederikshavn), Knotterne Islands (small islets east of Laesø Island), Vejlerne (diked in, landlocked fjords, densely covered with vegetation, at the Lim Fjord), Tipperne Peninsula and Klaegbanken Island (in Ringkøbing Fjord, western Jutland), Varsø Island (Horsens Fjord, eastern Jutland), and Græholm Island (Christiansø Archipelago, in the Baltic off Bornholm). A detailed description of these sites and their erection, bird life, and ornithological value was given by Salomonsen (1945). More recently, two additional Scientific Reserves have been established: Aegholm Islet (south of Sealand), and Hesselø Island in the southern part of Cattegat.

In addition to these scientific sanctuaries, there are game reserves and governmental forest reserves in Denmark. The game reserves are administered by the Ministry of Agriculture, which is also responsible for hunting legislation. The purpose of game reserves is to support and protect the stock of game, which includes migrating birds. Shooting is usually prohibited, but a restricted shooting season is allowed at some reserves. More than 50 game reserves are now present and functioning. Regulations differ widely from reserve to reserve, but entry to some of them is not allowed in the breeding season. Many reserves are important for breeding or migrating waterfowl and some seabirds. In fact, a total of 26 game reserves contain seabirds, the most important of which are the following: Ulvedybet (landlocked fjord at the Lim Fjord), Hjarbaek Fjord (landlocked fjord with brackish water at the Lim Fjord), Felsted Kog (landlocked fjord at Nissum Fjord), Jordsand (large stretches, almost 11,000 ha, of the Danish Waddensea), Stavns Fjord (at Samsø Island), Esrum Lake (in northern Sealand), and Kalvebod Beach (at Amager Island, near Copenhagen).

In the Nature Conservancy Act of 1969, differences between scientific and game reserves were abolished, although regulatory provisions that were in force for the scientific sanctuaries were maintained. Unfortunately, the amalgamation of the two types of reserve has given more power to the hunters' associations, which constitute the majority of the administrative body of the reserves, the so-called Game Commission ("Vildtnævnet"). However, any change in status of the original scientific reserves will not be tolerated by conservationists and other environmental groups in Denmark.

The Faroe Islands

The number of seabirds in the Faroe Islands is greater than in any other region of the North Atlantic, and is closely related to the extraordinary richness of the plankton. The high phytoplankton production is due to a strong vertical mixing of the water in the northeast Atlantic, especially at the slopes of the submarine ridges, where both tidal currents and oceanic currents are usually strong. The resulting upwelling enriches the upper layers of water with large quantities of nutrient salts for the phytoplankton, and this, in turn, produces a teeming life of macroplankton and fish on which the seabirds are dependent (Salomonsen 1955).

The enormous seabird population of the Faroes is apparent from the first description of the islands, "De mensura orbis terrae," a document written in the year 825 by the Irish monk Dicuilus, who described the most characteristic feature of the Faroes as being the fact that "the islands were full of various kinds of marine birds." This richness has remained to the present, and has provided an important source of food for the resident human population, particularly in former times. There are few, if any, countries in the world in which wild-fowling and other exploitations of birdlife have played such a major role as in the Faroes. A number of elaborate and varied bird-catching methods were invented, and these have remained essentially the same for at least the last 500 years. Bird-fowling at great heights on precipitous sea-cliffs was a dangerous venture, and each year lives were lost. The main thing, however, was that food obtained from fowling meant life and death for local inhabitants and so was undertaken in such a well-balanced way that the seabird populations did not decrease or disappear. Some fowling still takes place, but on a reduced scale, since most men are now engaged in the fishery during the summer. Shooting is now of much greater importance than in former times.

The Faroese game acts (from 1897, 1928, and 1954) are very severe and show a broad consideration for birdlife. Practically all terrestrial birds, including shorebirds, are protected, and existing regulations permit people to catch or shoot only common murres, razorbills, puffins, shags _(Phalacrocorax aristotelis)_, fulmars, gannets, parasitic jaegers _(Stercorarius parasiticus)_, and gulls, as well as a few "pest" species like crows _(Corvus corone)_ and ravens _(C. corax)_. The legal right of fowling on a "fowling cliff" belongs to the registered owner of the land on which the cliff is situated. There are some sound restrictive laws for these cliffs. For example, shooting within 3.2 km of any seabird colony is prohibited.

Table 5. _Number of seabirds caught by fowling each year in the
Faroe Islands in the early 1900's._ (From Salomonsen 1935.)

--------------------------------------
Number of birds
Species caught per year
--------------------------------------
_Uria aalge_ 60,000
_Fratercula arctica_ 270,000
_Puffinus puffinus_ 1,500
_Fulmarus glacialis_ 80,000
_Morus bassanus_ 1,300
Total 412,800
--------------------------------------

The annual number of seabirds caught by fowling in the early 1900's (summarized in Table 5) were reported in Salomonsen (1935). This large harvest of birds, taken by fowling year after year for centuries, did not appear to influence the seabird populations, as bird numbers remained stable. However, in recent years, shooting and a special form of snaring of murres have increased dramatically and seem to have endangered the murre population. The annual number of murres killed is estimated to be about 120,000, of which 70,000 are snared and at least 50,000 shot (estimates of birds shot range from 50,000 to 100,000). This total is almost double the number of birds caught during fowling, and because of an apparent decline in murre numbers the provincial government decided to investigate the matter, and in 1972 the Danish Ornithological Society agreed to conduct the study. Figures from the 1972 census of murres (Table 6) show that almost 600,000 birds were counted, from which an estimate of more than 393,000 breeding pairs was calculated (Dyck and Meltofte 1975). In spite of this large number, Dyck and Meltofte (1975) concluded that the Faroese murre population has declined by about 20% during the last 10-15 years. Investigations are under way to monitor further changes in murre numbers, and to determine the trend, and whether reductions in shooting and snaring are necessary to maintain the population.

Oil pollution is practically unknown in Faroese waters, but since drilling for oil will probably take place in the near future, the importance of oil to birds in this region may change. Toxic chemicals do not appear to be involved in the decline in murres. Investigations of concentrations of chemical pollutants in their eggs show that levels of DDE (mean 1.1 ppm), PCB (mean 2.0 ppm), and mercury (mean 0.2 ppm) (Dyck and Meltofte 1975) are relatively low and unlikely to affect reproduction (Dyck and Meltofte 1975). Levels are much smaller than those found in seabirds in Britain, the Baltic, or in albatrosses in the Pacific (Fisher 1973).

Table 6. _Colonies of the common murre,_ Uria aalge, _on the
Faroe Islands, based on a census conducted in 1972._ (After Dyck
and Meltofte 1975.)

----------------------------------------------
Number of
birds Number of
Colony observed pairs[72]
----------------------------------------------
Suderoy 73,945 49,500
Lítla Dímun 13,220 8,800
Stóra Dímun 68,050 45,600
Sandoy 101,710 68,100
Hestur 17,290 11,600
Mykines 14,500 9,700
Vágar 4,224 2,800
Streymoy 27,214 18,200
Eysturoy 10,520 7,000
Kalsoy 14,150 9,500
Vidoy 5,980 4,000
Fugloy 22,730 15,200
------- -------
Totals 587,333 393,200[72]
----------------------------------------------

Greenland

Greenland, which has an area of 2,175,600 km² and extends for a distance of 2,670 km from the northernmost to the southernmost point of the country, is almost a continent by itself. The range of the different species of seabirds, therefore, is greatly varied, and it is necessary to classify them according to the relation between their distributions and the marine zones. A description of the zones of the marine environment in the North Atlantic was given by Salomonsen (1965), and the breeding distributions of seabirds in Greenland based on this system are given in Table 7. The terrestrial area of southernmost West Greenland belongs to the subarctic zone of the boreal province, and one boreal bird species, the black-headed gull, has bred there in recent years. It is, however, as much a freshwater bird as a marine one.

Table 7. _Distributions of seabirds breeding in Greenland in
relation to marine zones._

Marine zone and species[73]

Boreo-panarctic
_Fulmarus glacialis_
_Somateria mollissima_
_Stercorarius parasiticus_
_Rissa tridactyla_
_Sterna paradisaea_
_Cepphus grylle_
_Fratercula arctica_
Panarctic
_Larus hyperboreus_
_Uria lomvia_
_Clangula hyemalis_
_Gavia stellata_
High arctic
_Somateria spectabilis_
_Branta bernicla_ _(hrota)_
_Stercorarius longicaudus_
_Xema sabini_
_Larus thayeri_
_Pagophila eburnea_
_Cepphus grylle_ (_mandti_ group)
_Plautus alle_
_Fratercula arctica_ _(naumanni)_
_Phalaropus fulicarius_
Low arctic
_Larus glaucoides_
_Phalaropus lobatus_
Boreo low arctic
_Mergus serrator_
_Phalacrocorax carbo_ _(carbo)_
_Larus marinus_
_Alca torda_
_Uria aalge_
_Cepphus grylle_ (_grylle_ group)
_Fratercula arctica_ _(arctica)_
Boreal
_Larus ridibundus_

The widely differing ranges of Greenland seabirds are shown in Figs. 1-4 and are based on my new and previously unpublished data. The borderline between the high arctic and low arctic zones is situated in Melville Bay on the west coast, and just south of Scoresby Sound on the east coast; the innermost parts of Scoresby Sound belong to the low arctic zone.

In the low arctic Pacific region the number of seabirds is said to be about 51 million in summer and 8 million in winter (Sowl and Bartonek 1974). No similar estimate is available for low arctic West Greenland, but I suggest that it is much lower in summer and slightly higher in winter.

The human population of Greenland, now numbering about 50,000 individuals, is restricted to the seashore, where all cities and minor outposts are situated. Although shooting seabirds is an ancient tradition in Greenland, the true land-birds, which are few in number, are usually left alone. Seabirds collected by shooting provide an important source of food that the Greenlanders could not do without. Since special shooting and hunting regulations have not been developed in Greenland, these activities often resemble a sort of slaughter rather than true hunting. There is no game act in Greenland, and practically all birds can be shot. This condition is similar to that in Canada, where according to Section 5(7) of the Migratory Birds Regulations (Canadian Wildlife Service, Ottawa 1973) "an Indian or Inuk may at any time, without a permit, take auks, auklets, guillemots, murres, puffins and scoters and their eggs for human food and clothing." Much the same sort of hunting privileges exist for native peoples of Alaska. What is still worse, however, is the enormous illegal shooting of ducks, geese, swans, and cranes that is known to take place in arctic North America, but is largely ignored by police and game authorities. Bartonek et al. (1971) described this situation very well for Alaska. In Greenland, it is not possible any more to distinguish between "native Eskimos" and Greenlanders (including Danes working in the country), but the attitude toward animals among the inhabitants is the same as it has always been--a food source to hunt and kill.

With a rapidly growing human population, and a readily available supply of guns and speedboats for hunting, the whole natural ecosystem is beginning to break down, and it cannot be permitted to continue. The provincial government is aware of this fact, and various legal enactments have been issued from both the government and the local magistrates. However, since the size of the police force (mostly Greenlanders) is small, it is of little help for the preservation of wildlife, and sometimes even the policemen themselves do not know the local ordinances. The result has been that seabirds, previously profusely flourishing, have considerably decreased in number in West Greenland.

I have previously described the shooting and hunting of seabirds in Greenland and the statutory provisions issued to protect them (see Salomonsen 1970). At present, the following seabirds and their eggs are totally protected: whooper swan; common puffin, _Fratercula arctica_; and harlequin duck, _Histrionicus histrionicus_. Some other species have a closed season or are protected in certain parts of the country: snow goose, _Anser caerulescens_; common eider; king eider, _Somateria spectabilis_; great cormorant; dovekie, _Plautus alle_; black guillemot; and thick-billed murre, _Uria lomvia_. Furthermore, all catching and hunting of birds within 2 km of breeding colonies of murres and kittiwakes is prohibited. Bird sanctuaries where hunting, catching, and collecting of eggs and down are prohibited are Avsigsut, Nunatsiaq, and Satuarssunguit islands, which are scattered in Disko Bay, and Tasiussarssuaq Fjord (the inner part of Arfersiorfik Fjord, south of Egedesminde).

However, the Greenland Provincial Council has been alarmed by the serious decline in the numbers of seabirds due to increases in human persecution, and it has decided to introduce a game law similar to those in Denmark and other European countries. The preparation of this legislation was left to me, and a draft of this Greenland game act has been issued (Salomonsen 1974); the new law was passed in parliament in 1977 and went into force on 1 January 1978.

It is not possible to review in detail the different parts of the new law, but certain important points should be mentioned. In northern parts of West Greenland (north of Egedesminde) the sea is ice-covered for 7-8 months a year, and seabird hunting is therefore not possible outside the breeding season. Because of this, it was necessary to allow some hunting of murres, eiders, and immature gulls during the breeding period, but away from nesting locations. Consumption of seabirds is to be limited to local residents, and sales to canneries for shipment to other cities is to cease. Previously, canneries in northwest Greenland exported large numbers of thick-billed murres to South Greenland--e.g., 25,606 birds in 1971; and 30,029 in 1972 (Anonymous 1974:64). This marketing of murres will end.

Other parts of the proposal important for seabirds include:

• A general closed season extending from 15 June to 15 August.

• Prohibition of shooting at breeding colonies of seabirds, as is in force at present (cf. above).

• Eggs of terns and gulls can be collected for food in southwest Greenland to 1 July, and in northwest Greenland to 10 July; fulmar and murre eggs can also be collected in northwest Greenland.

• Each hunter is allowed to shoot or catch 50 birds per day, but the entire bag must be used for human consumption.

• All shooting from speedboats, aircraft, and motor vehicles is prohibited.

• Catching flightless common eiders, king eiders, and oldsquaws _(Clangula hyemalis)_ is prohibited.

• Practically all seabirds and shorebirds can be shot; all other birds (except rock ptarmigan and raven) are totally protected.

The principles of this radical new act must be taught to the population by all possible means of communication, including radio, public meetings, schools, etc.

* * * * *