236 



J. G. KING AND G. A. SANGER 



Table 3. Oil Vulnerability Index (OVI) for families of birds of the Northeast Pacific marine habi- 

 tats, excluding rare and endangered species in the scoring. 



or less again relates to simplicity. This ap- 

 pears to be the minimum number that will as- 

 sure species separation and that can be neatly 

 displayed. 



The system will be much more useful when 

 it is expanded to the subspecific level. Many 

 Holarctic species are represented in the 

 Northeast Pacific by a single race that would 

 have a much higher OVI than the species as a 

 whole. For example, the OVI for the Peale's 

 peregrine falcon (Falco peregrinus pealei) con- 

 fined to marine habitats within the Pacific re- 

 gion would be high; and the endangered Aleu- 

 tian Canada goose (Branta canadensis leuco- 

 pareia) would score 100 points instead of the 

 34 we show for Canada geese (B. c.). If Tables 

 4 and 5 showed subspecies, the differences in 

 value would be more marked. 



Tables 4 and 5 are for broad geographical 

 areas. A comparison between smaller areas 

 would probably show more dramatic dif- 

 ferences. 



Because the dearth of easily available, ap- 

 plicable information poses a problem in 



evaluating the various factors, our scoring 

 was conservative. Experts on the various 

 avian families can doubtless refine the scor- 

 ing. If this system proves useful, investiga- 

 tors will begin to acquire the information 

 needed for more precise evaluations. Ultimate 

 perfection may never be achieved; however, as 

 with the field guides, the fact of minor profes- 

 sional disagreement should not destroy the 

 system's utility. 



We believe rescoring of all birds on the basis 

 of various projects should be avoided because 

 a standard against which individual projects 

 can be measured is needed. If everyone did 

 their own scoring, there would be no standard, 

 and projects evaluated by different investiga- 

 tors would not be comparable. If a species list 

 for the project area and standard point scores 

 are used, the level of involvement for many 

 species and perhaps for most species will be 

 properly identified. As with any system, there 

 will be exceptions and the assessor will need 

 to deal with these as appropriate. The result 

 will still be to focus attention on those species 



