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49 <br />PART Il RECOVERY <br />A. Objective and Criteria: To downlist the whooping crane from endangered to <br />threatened status by increasing the wild population to 90 <br />nesting pairs in three separate populations by 2020. <br />Part I described the biology of whooping cranes, the factors that lead to endangerment, and <br />research and management progress to date. Throughout the discussions the Recovery <br />Team has briefly referred to information needs and plans for the future. Although the <br />progress to date has been substantial, much still must be done before the whooping crane <br />can be downlisted from Endangered to Threatened status. The actions proposed in this Plan <br />will, with high probability, result in sufficient improvement in the status of whooping crane <br />populations so that official listing can be changed from Endangered to Threatened. Based <br />on the past history of this species, the low reproductive rate, and threats to habitat required <br />for breeding, migration, and wintering, the whooping crane may never be an abundant <br />species. Preservation of this species will require the interest and concern of an informed <br />public. The present numerical goals for downlisting are best estimates of the numbers for <br />population viability and may need to be modified in the future as additional information <br />becomes available. <br />The first recovery goal for the whooping crane is a change in status from Endangered to <br />Threatened. Based on existing knowledge, the minimum requirements for downlisting are <br />maintenance of the AWP above the current 40 nesting pairs and the establishment of at <br />least two additional, separate and self- sustaining populations, each consisting of 25 nesting <br />pairs. The Service proposes to promote growth of the AWP to 1,000 individuals, a level <br />that is likely to allow survival as a population despite any future catastrophic event. These <br />populations may be migratory or nonmigratory. These goals should be attained for 10 <br />consecutive years before the species is reclassified to Threatened. That goal is unlikely to E <br />be reached before year 2020. A goal for delisting the species will be set prior to <br />downlisting sometime in the 21 st Century. <br />By identifying three self- sustaining wild populations as a requirement for downlisting, the <br />Service recognizes the need for multiple populations for protection against stochastic, <br />catastrophic events in nature. At their 1988 meeting, the recovery team concluded there <br />was no minimum number of birds considered sufficient in the wild as long as there is only <br />one population. Therefore, the Service believes a single wild population remains vulnerable <br />to extinction during one, or a series, of adverse events, regardless of the size of the single <br />population. A single large population cannot substitute for the greater security provided by <br />multiple, discrete populations. <br />To attain reintroduction goals, it is proposed that about 40 captive breeding pairs of <br />whooping cranes be in place by year 2000. The 40 breeding pairs will be comprised of 15 <br />pairs at PWRC, 15 at International Crane Foundation, and 10 at Calgary Zoo. Production <br />from ICF and Patuxent will be the principal source of release birds in the Florida <br />reintroduction effort for the balance of this decade, if that reintroduction seems promising <br />and is continued after the first 2 years of the experiment. However, sources of release bir <br />should be based on the optimal genetic mix to ensure long -term viability of the population. <br />