Recovery Plan for the Northern Spotted Owl - DRAFT
Recovery Plan for the Northern Spotted Owl - DRAFT Recovery Plan for the Northern Spotted Owl - DRAFT
320
1. IntroductionThe 1990 Status Review Northern Spotted Owl (USDI 1990) provided estimatesof the rate of population change for populations of northern spotted owls innorthern California (Willow Creek and surrounding regional study area) andsouthern Oregon (the Roseburg study area). The population of resident femaleowls in these areas was shown to be declining at a significant rate. By the fallof 1991, there were 2 additional years of capture-recapture data on these twopopulations, and three new areas (Medford in southern Oregon, H.J. Andrewsnear Corvallis, Oregon, and the Olympic Peninsula in northwestern Washington)had sufficient years of capture-recapture data to warrant an intensiveanalysis (Table C. 1). More than 2,000 owls had been marked and theresighting probability for adult females was approximately 0.8 to 0.9 percent.This appendix provides estimates of the rate of population change of resident,territorial females in these five large study areas. Analysis methods (e.g.,model building, model selection, tests of model fit, parameter estimation, andinference procedures concerning the rate of population change) are those usedin USDI (1990) with some extensions. The key references on methodology areBurnham and Anderson (In Press) and Lebreton et al. In Press). The analysesof data were done during September-October 1991, during two intensiveworkshops held in Fort Collins, Colorado. The analyses were completed by sixbiologists working on the northern spotted owl-two French scientists, twoprofessors from Colorado State University with special expertise in the analysisof capture-recapture data, and two U.S. Fish and Wildlife Service employeesfrom the Colorado Cooperative Fish and Wildlife Research Unit.2. Results and DiscussionTwo parameters are of critical interest; A = finite (i.e., annual) rate of change inthe size of the population of females, and $ = annual probability of survival ofadult females. Maximum likelihood estimates of these parameters are shownas A and $, respectively, along with estimates of their precision (i.e., se (A) ande ($)). If the number of resident females is 'stationary," then X = 1, while if thepopulation is declining, then X < 1. Thus, there is interest in testing the nullhypothesis Ho: X < 1 against the alternative hypothesis Ha: X < 1. Proper estimationof X answers the critical question, "Have the resident, territorial femalesreplaced themselves?"/Table C.1. Summary information on the five demographic study areas.TotalApproximate Size Years of IndividualsName of Study Area Marking MarkedNorthwest California 4,000 1985-91 400H.J. Andrews (western Oregon) 116 1987-91 358Medford (southwestern Oregon) 4,050 1985-91 703Roseburg (southwestern Oregon) 1,700 1985-91 589Olympic Peninsula (northwestern Washington) 965 1987-91 302321
- Page 286 and 287: Table A.8. Summary of information n
- Page 288 and 289: predict the power achieved by diffe
- Page 290 and 291: Other studiestached. If dispersing
- Page 292 and 293: impractical at present. We describe
- Page 294 and 295: Conclusionsthe year effect can be i
- Page 296 and 297: 280
- Page 298 and 299: 282
- Page 300 and 301: 284
- Page 302 and 303: owls. Consequently, the issue of wh
- Page 304 and 305: Use of the informationAssessments a
- Page 306 and 307: Recent LiteratureWe might begin by
- Page 308 and 309: Kerms (1989) measured habitat struc
- Page 310 and 311: Hamer (pers. comm.) described 11 ne
- Page 312 and 313: Table B.3. Percent hardwoods in the
- Page 314 and 315: Table B.5. Comparison of habitats u
- Page 316 and 317: Table B.8. Tree density (number of
- Page 318 and 319: and numbers of trees, and percent o
- Page 320 and 321: Under this hypothesis, owl fitness
- Page 322 and 323: suitable habitat for that region (m
- Page 324 and 325: ResultsDiscussionspotted owl habita
- Page 326 and 327: __Discussiondata from 41 sites in t
- Page 328 and 329: Recommendations for Future Research
- Page 330 and 331: 314
- Page 332 and 333: Hamer, T. 1988. Home range size of
- Page 334 and 335: 318
- Page 338 and 339: Parameter Estimatesfor Individual S
- Page 340 and 341: provided in Table C. 5. Study of th
- Page 342 and 343: Table C.6. Summary of statistics re
- Page 344 and 345: 3. ConclusionsThis source of bias i
- Page 346 and 347: 330
- Page 348 and 349: Gray Wolf .........................
- Page 350 and 351: formed during the initial meeting t
- Page 352 and 353: provide habitat for the numerous sp
- Page 354 and 355: The ApproachA committee of the Reco
- Page 356 and 357: The List of Threatened and Endanger
- Page 358 and 359: Mammalsoldest trees in a stand. Eig
- Page 360 and 361: ABBFigure D. 1. Distribution of: a)
- Page 362 and 363: KTable D.3. A list of threatened an
- Page 364 and 365: Fishestheir dispersal capabilities
- Page 366 and 367: OlympicNorthcoastalRockyMountainSou
- Page 368 and 369: continued-StatusabState Considered
- Page 370 and 371: continued-SpeciesColumbia sidebandM
- Page 372 and 373: endemic to the Pacific Northwest).
- Page 374 and 375: ------continued-SpeciesRhyacophila
- Page 376 and 377: continued-SpeciesFed3tatusa bStateW
- Page 378 and 379: StatusasbOld ForestState Associatio
- Page 380 and 381: Summaryspores (Maser et al. 1978b).
- Page 382 and 383: Biology of Owl Prey, Older Forest A
- Page 384 and 385: Woodrats.-The dusky-footed woodrat
1. IntroductionThe 1990 Status Review Nor<strong>the</strong>rn <strong>Spotted</strong> <strong>Owl</strong> (USDI 1990) provided estimatesof <strong>the</strong> rate of population change <strong>for</strong> populations of nor<strong>the</strong>rn spotted owls innor<strong>the</strong>rn Cali<strong>for</strong>nia (Willow Creek and surrounding regional study area) andsou<strong>the</strong>rn Oregon (<strong>the</strong> Roseburg study area). The population of resident femaleowls in <strong>the</strong>se areas was shown to be declining at a significant rate. By <strong>the</strong> fallof 1991, <strong>the</strong>re were 2 additional years of capture-recapture data on <strong>the</strong>se twopopulations, and three new areas (Med<strong>for</strong>d in sou<strong>the</strong>rn Oregon, H.J. Andrewsnear Corvallis, Oregon, and <strong>the</strong> Olympic Peninsula in northwestern Washington)had sufficient years of capture-recapture data to warrant an intensiveanalysis (Table C. 1). More than 2,000 owls had been marked and <strong>the</strong>resighting probability <strong>for</strong> adult females was approximately 0.8 to 0.9 percent.This appendix provides estimates of <strong>the</strong> rate of population change of resident,territorial females in <strong>the</strong>se five large study areas. Analysis methods (e.g.,model building, model selection, tests of model fit, parameter estimation, andinference procedures concerning <strong>the</strong> rate of population change) are those usedin USDI (1990) with some extensions. The key references on methodology areBurnham and Anderson (In Press) and Lebreton et al. In Press). The analysesof data were done during September-October 1991, during two intensiveworkshops held in Fort Collins, Colorado. The analyses were completed by sixbiologists working on <strong>the</strong> nor<strong>the</strong>rn spotted owl-two French scientists, twoprofessors from Colorado State University with special expertise in <strong>the</strong> analysisof capture-recapture data, and two U.S. Fish and Wildlife Service employeesfrom <strong>the</strong> Colorado Cooperative Fish and Wildlife Research Unit.2. Results and DiscussionTwo parameters are of critical interest; A = finite (i.e., annual) rate of change in<strong>the</strong> size of <strong>the</strong> population of females, and $ = annual probability of survival ofadult females. Maximum likelihood estimates of <strong>the</strong>se parameters are shownas A and $, respectively, along with estimates of <strong>the</strong>ir precision (i.e., se (A) ande ($)). If <strong>the</strong> number of resident females is 'stationary," <strong>the</strong>n X = 1, while if <strong>the</strong>population is declining, <strong>the</strong>n X < 1. Thus, <strong>the</strong>re is interest in testing <strong>the</strong> nullhypo<strong>the</strong>sis Ho: X < 1 against <strong>the</strong> alternative hypo<strong>the</strong>sis Ha: X < 1. Proper estimationof X answers <strong>the</strong> critical question, "Have <strong>the</strong> resident, territorial femalesreplaced <strong>the</strong>mselves?"/Table C.1. Summary in<strong>for</strong>mation on <strong>the</strong> five demographic study areas.TotalApproximate Size Years of IndividualsName of Study Area Marking MarkedNorthwest Cali<strong>for</strong>nia 4,000 1985-91 400H.J. Andrews (western Oregon) 116 1987-91 358Med<strong>for</strong>d (southwestern Oregon) 4,050 1985-91 703Roseburg (southwestern Oregon) 1,700 1985-91 589Olympic Peninsula (northwestern Washington) 965 1987-91 302321