SYMPOSIUM SUMMARY 



307 



tailed shearwater, a migrant from the south- 

 ern hemisphere. The rarest species, and the 

 most endangered, is the short-tailed alba- 

 tross, which breeds only on one island in 

 Japan. There are migrants in large numbers 

 from Chile, Australia, New Zealand, and espe- 

 cially the Soviet Union. All of these use the 

 area of ocean and shallow sea that we have 

 been considering as a major area for a sub- 

 stantial part of their annual cycle. 



What more do we need to know about the 

 extent of this resource? In my opinion we 

 should not place high priority on determining 

 the exact numbers of the birds whether 

 there are 25 million or 26 million murres, for 

 example. It would be difficult, if not impos- 

 sible, to determine such numbers in the kind 

 of geographical and climatic area we are con- 

 sidering. Moreover, even if we were to meas- 

 ure the populations with great accuracy and 

 to determine in a few years that they had 

 changed by 10%, we would not be able to 

 draw any conclusions about the reasons for 

 the change or what should be done about it. 



To set priorities for further exploration, I 

 think it is more important to survey in greater 

 detail the general distribution of the breeding 

 colonies. So far, we know the location of only 

 the largest colonies; we know almost nothing 

 about the colonies of a mere 10,000 pairs or 

 less. So I think future surveys should concen- 

 trate on locating the medium-sized colonies 

 and getting some impression of roughly how 

 many smaller colonies there are. It is impor- 

 tant to locate and be sure that we know of all 

 the major colonies that have a considerable 

 number of species; these large, diverse colo- 

 nies should be given priority for conservation. 

 Most important of all, we need to locate and 

 survey the endemic species with some preci- 

 sion. This need is especially great for the 

 species that we suspect are limited to small 

 areas or that may otherwise be particularly 

 vulnerable. 



If we are to measure population changes 

 over the next few decades, it is of course es- 

 sential to have a good base-line survey. How- 

 ever, I do not think it is either practicable or 

 desirable to try to inventory the entire popu- 

 lation of breeding seabirds with great accu- 

 racy. A more realistic and worthwhile pro- 

 gram would be to select some sample colonies 

 and to catalogue these sample areas in some 



detail, preferably with a photographic record, 

 so that they can be resurveyed in later years 

 to determine whether substantial population 

 changes have taken place. Criteria for selec- 

 tion of sample colonies for inclusion in this 

 base-line survey should include not only 

 numerical size and species diversity but also 

 ease of access, ease of observation, and the 

 practicability of obtaining good photographic 

 records. 



Ecology and Functioning 

 of the Resource 



In the opening session of this conference, 

 several speakers reviewed our general knowl- 

 edge of the ecology of seabirds; others sum- 

 marized our specific knowledge of the birds of 

 the North Pacific, Bering, and adjacent seas, 

 and their relation to physical and biological 

 factors in the environment. There is no need 

 to summarize these reviews again here except 

 to point out that information on the relation 

 between the birds and the marine environ- 

 ment is being generated very rapidly. We are 

 beginning to understand the factors that con- 

 trol the breeding distribution of the individual 

 species, their foraging strategies, and their 

 dispersion at sea, at least in summer. How- 

 ever, it is clear from what has been said at this 

 conference that we know much less about 

 their ecology and distribution in winter. This 

 lack of information is important because con- 

 flicting opinions have been expressed as to 

 whether factors operating in the winter range 

 or at the breeding colonies are more critical in 

 limiting population size. 



It is evident from what was said in the open- 

 ing session that the distribution of the birds is 

 very closely related to the distribution of 

 marine resources. It is clearly no accident that 

 the distribution of large numbers of many 

 species of birds coincides with that of the 

 major fisheries. Similarly, it is no accident 

 that there is a relation between the distribu- 

 tion of birds and the extent of the continental 

 shelf. These coincidences, which reflect the 

 fundamental dependence of both birds and 

 fish upon marine productivity, set the stage 

 for existing and further conflicts between con- 

 servation of the birds and human exploitation 

 of other resources of the area. 



