No process designed to identify species at risk is going to satisfy everyone, and that certainly applies to the current document. Many people will question why particular species are not listed. For example, 470 of the 570 species evaluated in the Delphi exercise were considered to be of Moderate or High concern by one or more participants, yet only 72 of them met the Delphi criteria for listing. Others may question the appearance on the list of such widespread and abundant species as the eastern meadowlark and field sparrow, although we believe that their inclusion (based on the BBS criterion) is biologically justified. Overall, we feel that the five-step process yielded a comprehensive and reasonably sound list of species most deserving of additional conservation actions at a national level.
In particular, we feel that the Delphi exercise was a positive addition to the process. The Delphi exercise has been criticized by some reviewers as being too subjective. Although the process requires that participants make subjective value judgments, the selection criteria (i.e., a score of Moderate or High concern by more than 50% of all (minimum of 5) respondents) is conservative enough to ensure considerable confidence in the results. For example, the cumulative Delphi scores of the 72 species selected by this criterion have a much higher proportion of Moderate and High values than those of all other nongame birds combined (71% vs 15%, P < 0.01). Furthermore, the distribution of Delphi scores of 66 (92%) of the 72 selected species differs significantly (P < 0.05) from that of the nongame bird community at large.
Some reviewers commented that the combination of BBS and PIF criteria resulted in a bias against wetland birds. Most wetland birds are poorly monitored by the BBS, thus reducing a species' chance of being selected by this criterion, and the PIF criterion specifically excludes most wetland birds from consideration. Despite this bias, two major groups of wetland birds (herons and non-harvested waterfowl, and rails) are represented on the list by larger numbers of species than expected. To guard against potential biases in future lists, it would be beneficial to include a criterion that uses status information from the The Nature Conservancy's Natural Heritage Program. Consideration should also be given to incorporating information from the International Shorebird Survey and the various colonial waterbird databases.
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