these are ducks, but many other species are also involved (Riisgard 1979). Oil 

 has caused major losses in populations of Common Eiders in the Danish Waddensea 

 (Joensen 1973), in breeding populations of Common Eiders and Black Scoters in 

 Holland (Swennen and Spaans 1970) , and in populations of the Atlantic Puffin 

 ( Fratercula arctica ) in France (Bourne 1976). Oil is also a major cause of 

 death for Jackass Penguins ( Spheniscus demersus ) in South Africa (Randall et 

 al. 1980). 



Other losses reported include the death of an estimated 25-50% of the Com- 

 mon Loons wintering in Shetland, off Scotland, following the ESSO BERNICLA oil 

 spill on 30 December 1978 (Stowe and Morgan 1979), and the loss of all Mallards, 

 European Coots ( Fulica atra ) , and Moorhens (= Common Gallinule, Gallinula chlor - 

 opus ) following an oiling of the Amer River in the Netherlands; it was estimated 

 that approximately 88% of the Greylag Geese ( Anser anser ) and about 71% of the 

 Bewick's Swans ( Cygnus columbianus bewickii ) would ultimately be lost as well 

 (Belterman 1972). Still other examples of major or significant reductions in 

 avian populations due to oil pollution are given in reviews by Bourne (1968b, 

 1976), Croxall (1975), Vermeer and Vermeer (1975), and Food and Agricultural Or- 

 ganization of the United Nations (1977). 



VARIABILITY IN SPECIES' SUSCEPTIBILITY TO OIL POLLUTION 



Surveys of beached birds are biased indicators of what proportion of a pop- 

 ulation is affected by oiling (Bourne 1976). However, the proportions of spe- 

 cies found oiled gives some idea of differences in susceptibility between dif- 

 ferent groups of birds and also suggests the magnitude of the oil pollution 

 problem for a given area. Such surveys also provide data on seasonal variation 

 in the incidence and extent of oil pollution. Table 1 gives the percentage of 

 beached birds that were oiled in four different areas. Species such as loons, 

 grebes, auks, and seaducks are most affected, whereas more aerial species such 

 as gulls and terns are usually among the least affected. 



REGIONAL DIFFERENCES IN OILING AND MORTALITY OF BEACHED BIRDS 



Although beached bird surveys in the eastern United States have been con- 

 ducted for only a relatively short time, the extent of oiling in birds found 

 dead along the southern Atlantic coast appears low compared with other areas in 

 the United States and elsewhere. Only 4% of 400 birds found dead along the 

 south Atlantic coast from January 1976 through August 1978 were oiled. In con- 

 trast, oiling occurred in 82% of 667 birds found along the Polish Baltic coast 

 from November 1974 to August 1975 (Gorski et al. 1977), in 26% of 162 found 

 along Irish coasts from December 1977 to March 1978 (O'Keeffe 1978), in 79% of 

 3,431 found on the international beached bird surveys in Northwest Europe in 

 January-March 1975 (Lloyd 1976), and in 18% of 2,420 found along the California 

 coast in 1975 (Ainley 1976). 



Bird mortality per mile of beach also tends to be less in the southeastern 

 United States than in other areas (Table 2). Mortality figures for a heavily 

 polluted area, the Polish Baltic coast, (3.2 birds/km or 5.2/mi; Gorski et al. 

 1977) are considerably higher than for anywhere in the southeast. Other 



14 



