POPULATION DYNAMICS IN NORTHERN MARINE BIRDS 



135 



a. What are the effects of food abundance 

 in early spring on date of laying, clutch size, 

 and egg size? 



b. What effects do storms have at dif- 

 ferent stages of the reproductive schedule? 



c. What effects do quantitative and quali- 

 tative (species composition of prey) changes in 

 food supply have on the survival of chicks? 



d. What are the similarities and differ- 

 ences between what parents eat and what 

 they feed their chicks? 



Although this is important basic biologi- 

 cal knowledge, it contributes little to conser- 

 vation efforts because food differences result 

 from changes in the ocean over which humans 

 can have little effect. 



7. To learn more about prey species and 

 their availability to marine birds: 



a. To know more about the breeding 

 areas, reproductive rates, growth rates, and 

 routes of dispersal of the major prey food 

 species. In most areas a few species of teleost 

 fish (e.g., Ammodytes) or Crustacea (e.g., 

 copepods, euphausids, mycids, or amphipods) 

 make up most of the food of marine birds. Yet, 

 the barest minimum is known about the biol- 

 ogy of such species. A good first estimate of 

 the "condition" of the marine environment 

 can probably be made by measuring reproduc- 

 tive rates and growth rates of these key prey 

 species. Hence an efficient (though indirect) 

 way to measure those rates may be by moni- 

 toring reproduction of birds. 



b. To know more about the density and 

 distribution of key prey items season by sea- 

 son, and to learn more about the relation of 

 their abundance and distribution to their 

 availability to birds, as Bedard (1969) showed 

 for Calanus to least auklets, and Thysanoessa 

 to crested auklets. 



There are some indications that the popu- 

 lation size of prey items can vary widely with- 

 out having a marked effect on the numbers of 

 their predators. Does commercial fishing for 

 the large, predatory fish have a measurable ef- 

 fect on the food available to marine fish? Do 

 the large pollock and salmon fisheries (high 

 seas) make zooplankton available to smaller 

 alcids? Do marine birds affect a fishery? 



c. To know more about the oceanography 

 of continental shelf waters, more specifically 

 the waters between 6 and 60 m deep. The shal- 

 low waters of continental shelves are some of 



the most productive of sea waters, but are 

 among the least studied. Although some 

 species (black-legged kittiwakes, tufted 

 puffins, and fulmars) move into deep waters, 

 many species of marine birds of northern 

 waters gather in large numbers on preferred 

 feeding grounds at or near the edges of conti- 

 nental shelves during their winter season 

 (Fisher 1952; Tuck 1960). 



8. To know more about the potential effects 

 of proposed developments on seabirds and 

 waterfowl. 



a. To prepare models which will predict 

 probabilities of contamination of breeding 

 and feeding areas (summer, winter, and dur- 

 ing migration) using existing knowledge of 



(1) areas of proposed mineral develop- 

 ment; 



(2) areas that will be influenced by sec- 

 ondary development such as dredging new 

 harbors, laying subsurface pipelines; 



(3) tidal and oceanic currents; 



(4) numbers of marine birds or water- 

 fowl using specific geographic areas and habi- 

 tats (e.g., waters below nesting cliffs, feeding 

 grounds, wintering grounds, and gatherings 

 during migration); 



(5) the distribution and patchiness of 

 habitats (i.e., the redundancy among and 

 within habitats and the degree to which popu- 

 lations exchange between alternative 

 habitats); 



(6) the biological importance of species 

 in local ecosystems (Are they predators whose 

 effects increase diversity?); 



(7) the human importance of the species 

 (Are they endemics? Do they have unusual 

 "charisma" for the public?); 



(8) the vulnerability of the species (Is its 

 distribution restricted? Is it subject to oil pol- 

 lution? Are their preferred grounds near areas 

 of high development potential?); 



(9) the types of biological effects (e.g., 

 oil contamination of plumage, PCB contami- 

 nation of food chains); and 



(10) whether the potential impacts are 

 reversible or irreversible and to what degree. 



b. To understand more of the effects of 

 hunting on the behavior of marine birds and 

 waterfowl on their breeding grounds, and to 

 assess the effects on breeding performance of 

 changes in behavior which result from human 

 activities (such as hunting or studying the 



