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W. H. DRURY 



Goals for Research on 



Population Dynamics of Seabirds 



for Purposes of Conservation 



1. To learn the distribution and relative im- 

 portance of seabird colonies, the number of 

 pairs nesting and nonbreeding individuals at 

 each colony, and the timing of breeding activi- 

 ties for each geographical region. The most 

 important step toward conserving marine 

 birds is to get public ownership and protec- 

 tion for their breeding grounds. 



2. To understand the life cycle of key 

 species. Three needs are clear: 



a. To identify key species whose biological 

 characteristics can conveniently be studied 

 and measured. Studies of these species may 

 be useful in monitoring the "health" of sea- 

 bird breeding areas. 



If it is established that the reproductive 

 success of certain species varies similarly in 

 response to changes in their marine habitat 

 (such as black-legged kittiwakes and horned 

 puffins), one could use key species (black- 

 legged kittiwake) to assess the performance of 

 those species in a colony whose breeding suc- 

 cess is difficult to measure (horned puffin). 



b. To develop efficient and practical ways 

 of censusing and measuring productivity of 

 crevice-, scree-, and hole-nesting species such 

 as puffins and auklets. 



c. To establish annual differences in repro- 

 ductive success and mortality rates by age 

 classes of the key species, and from these to 

 identify rates of population turnover so as to 

 be able to predict the effects of mass mor- 

 talities. 



3. To learn enough about the differences in 

 behavior and productivity among colonies to 

 establish which colonies produce surplus 

 young and which have low productivity. At 

 first, maximum efforts for conservation 

 should be concentrated at those sites which 

 produce surplus young. 



4. To learn about colonial behavior. Two 

 needs are apparent: 



a. To know enough about the lives of indi- 

 vidually marked birds of known age so as to 

 be able to infer the behavior of population ele- 

 ments at all stages of their life cycle. 



b. To know enough about the lives of sub- 

 adult birds to understand what proportion of 



subadults visit and become established at 

 breeding sites, why the subadults visit the 

 breeding sites and what effect their presence 

 has on the territories and breeding success of 

 their neighbors and biological relatives. 



5. To know enough about places where sea- 

 birds, waterfowl, and shorebirds gather on mi- 

 gration and during the winter to identify 

 those areas which need special protection 

 from effects of economic development. 



a. It is important to determine the areas 

 where marine birds gather at sea when they 

 are away from their breeding grounds. What 

 factors of habitat and food supply make cer- 

 tain places preferable to others? What is the 

 relation between gathering grounds and 

 underwater topography (banks and edges of 

 the continental shelf)? What are the seasonal 

 and annual differences in preferred gathering 

 grounds? What special hazards exist, such as 

 unusual extent of sea ice or exceptional 

 storms? 



b. It is important to plot coastal areas 

 where waterfowl and shorebirds gather on mi- 

 gration, for molting, and during the winter. 

 Which open leads in the ice and patches of 

 open water at the mouths of rivers are of 

 especial importance in spring? What shore- 

 lines and beaches act as "leading lines" dur- 

 ing migration? Which capes and points result 

 in concentrated overflights of migrating 

 waterfowl, and hence are locations of un- 

 usually high kills by hunters? What wetlands, 

 bogs, coastal ponds, lakes, and lagoons are 

 used as gathering grounds and to what extent 

 do waterfowl and shorebirds exchange be- 

 tween gathering grounds? How much redun- 

 dancy of wetlands is needed to make the wet- 

 lands system maximally productive for water- 

 fowl and shorebirds? 



Answers to these questions will identify 

 which geographic areas deserve special pro- 

 tection during development. The answers will 

 also identify the kinds of influences which 

 might lower the contribution of each critical 

 area to the survival of seabirds, waterfowl, 

 and shorebirds. Areas identified as important 

 under these categories must be included in 

 policy decisions related to land-use planning 

 and management. 



6. To learn more about the effects of vary- 

 ing quantities of food on breeding behavior 

 and performance: 



