Recovery Plan for the Northern Spotted Owl - DRAFT

(Delisting Criterion 4: The population is unlikely to need protectionunder the Endangered Species Act during theforeseeablefuture.Hypothesis 1Long-term demographic projections, that include the effects offluctuations in abundance, fecundity, and survivorship, indicatethat there is a high probability of persistence of the population for100 years.Information needed to test hypothesis 1The data collected to answer questions about population anddemographic trends over time can be used in a modeling context torespond to this hypothesis. It is important to emphasize that, withinthe context of metapopulation dynamics, some DCA subpopulationsmay decline for a variety of reasons (e.g., catastrophic events,random demographic events) even when the metapopulation isstable. Therefore, delisting could occur in the province if themetapopulation as a whole were stable even though some DCAswould not be contributing fully for short periods.Hypothesis 2There are sufficient immigrants per generation among DCAs tomaintain demographic stability and genetic diversity.Information needed to test hypothesis 2Data are necessary for the number of immigrants per generationinto DCAs. These data can be collected best in conjunction with thestudies of demographic rates.Hypothesis 3Changes in amount and distribution of northern spotted owl habitatoccur at expected rates and result from expected causes.Information needed to test hypothesis 3Estimates over time of amounts and distribution of various classesof habitat are needed. These estimates must account for the developmentof suitable conditions on some areas and the loss of suitableconditions on others.-11- - -l- -- -- -----...I.........I... ............I.....-......- ... ......................_ 1 ............................ ................ ........................... _-- - ....The Recovery Team makes the following recommendations for study areas andtechniques for collection of information needed for delisting.Demography. Demographic study areas will provide information on demographic(i.e., vital) rates (e.g., age-specific, stage-specific rates of fecundity andsurvival, age at first and last reproduction) and the occurrence of immigration.These are large areas, tens to hundreds of square miles, where as many owlsas possible are banded. Banding is done on adult, subadult, and juvenile owls.Owls are observed on an annual basis on territorial sites, and young areobserved annually on nest sites. These observations are used to determineage-specific or stage-specific fecundity and mortality rates. Procedures fordeveloping some of these estimates are explained further in Appendices A andC. There are currently seven demographic study areas which should form thebasis for assessments of demographic trends within their respective provinces.These study areas are located in the following provinces: Olympic Peninsula;eastern Washington Cascades; western Oregon Cascades; Oregon Coast; andCalifornia Coast. An additional demographic area should be established in thewestern Washington Cascades. Three provinces - western Washington207