RECOMMENDATIONS 



POPULATION MONITORING 



This report should be useful to Federal, State, and local governments 

 and private organizations interested in the avian component of the coastal 

 ecosystem in Maine. The value of these data will be increased if inventories 

 can be repeated in the future. For most species, inventories at 3-year 

 intervals will be frequent enough unless ecological or environmental changes 

 indicate a need for more frequent inventories. 



This 2-year inventory demonstrated that not all waterbird colonies are 

 stable in terms of population numbers and colony location. Future inventories 

 will be most useful when they are based on intensive fieldwork to locate new 

 colonies and document disappearance of others. Censuses of only the known 

 largest colonies of each species would be difficult to interpret and extrapolate 

 in terms of total population trends. 



Aerial surveys in fixed-wing aircraft are valuable because they alert 

 observers to the location and size of some of the populations. Ground checks 

 of the colony sites are necessary to determine species composition and 

 estimate nesting pairs. Surveys by helicopter generally are not recommended 

 for the Maine colonies. Aerial photography is useful to estimate populations 

 of some species. Various census techniques should be correlated so that 

 accurate census data can be obtained. Behavioral studies to document nest 

 attentiveness, nesting chronology, and disturbance factors should be made 

 and interpreted to determine how species specific behavior affects population 

 estimates. 



PRODUCTIVITY OF COLONIES 



Censuses of breeding adults should be supplemented with long term 

 studies of the productivity of each species. In Maine the productivity of 

 species at different colony sizes, in different habitat regimes, and 

 geographical areas should be investigated. The large colonies may not always 

 be the ones with the highest productivity. Studies of those species which 

 now nest in abundance should have priority over those species which are on 

 the periphery of their historical breeding range and have sparse populations 

 in Maine. 



HABITAT REQUIREMENTS 



The nesting requirements of breeding waterbirds are fulfilled by 

 numerous islands in the coastal zone of Maine. Perhaps the best recommenda- 

 tion with regard to habitat requirements is to maintain colony sites in their 

 existing condition, except in those situations where predisposing causes for 

 population decline can be recognized, such as overgrazing by sheep. 



Controlled experiments to enhance the nesting substrates for particular 

 species could be attempted. Alcids may be receptive to artificial nesting 

 structures. More raspberry bushes, fallen spruce trees, or wooden shelters 

 might increase eider production by protecting nests from predation. 



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