Recovery Plan for the Northern Spotted Owl - DRAFT
Recovery Plan for the Northern Spotted Owl - DRAFT Recovery Plan for the Northern Spotted Owl - DRAFT
Table A.6. Reliability of trend estimates for red-tailed hawks in Wisconsin as afunction of interval Iengtha.NumberPercent of samples Inof Years which the error ( JX~ was:In Sample
analyses to determine effects of sample size, outliers, and autocorrelation butwere unable, with this small sample size, to reach definitive conclusions. Evenif we had, it would probably be difficult to predict the form of the spotted owldata set. For example, survey data on diurnal raptors such as the red-tailedhawk that inhabits open landscapes might be considerably different fromsurvey data for spotted owls. The analysis of Breeding Bird Survey datasuggests that obtaining "reliable" estimates might take 7 years to more than 15years, depending on one's definition of reliable and features of the data set.The analysis, while necessarily crude at present, provides no support forimagining that reliable estimates of trend could be obtained in fewer than 7 or8 years.Conclusions: We caution that these estimates provide only crude approximationsof the sample size requirements, especially concerning number of yearsrequired for reliable trend estimates. As noted earlier, accuracy, for a givennumber of years of survey data, depends on many factors, none of which iswell known at present for spotted owls. The analyses discussed earlier suggestthat a minimum of 8 years probably will be required to obtain trend estimatesreliable enough to be of any practical use, and the time certainly could bemuch longer, particularly if "bad years" have a pronounced effect on trends orif trends exhibit significant nonlinearity.ITable A.7. Number of years required to obtain reliable estimates of long-term trendsfrom sample Breeding Bird Survey data sets.Approximate, minimumnumber of years for 80 percentprobability that ( X- X) was:Species State c0.02 15 9 8Maryland 12 7 6Ohio 15 15 5Oklahoma 1 10 9Black vulture Alabama >15 13 10Florida 10 10 10Red-tailed hawk Kansas 8 7 4Oklahoma 14 8 7Wisconsin 5 13 6Red-shouldered hawk Florida 8 7 6American kestrel New York 8 6 5Ohio 8 8 8Ontario, Canada 13 10 8Osprey Florida 9 8 7Great horned owl Kansas 14 11 9aX. X-= estimate of trend minus true trend.I . 111.1 ...I... I.- 1. I.. I I . .. - - - 11- 1- - -.. .1.111 I1263
- Page 228 and 229: Stepdown Outline1. Management Tasks
- Page 230 and 231: Table 4.1 Abbreviated Cost TableThe
- Page 232 and 233: continued-TaskPriorityResp. PartyCo
- Page 234 and 235: 218
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- Page 238 and 239: and the number of invertebrate anim
- Page 240 and 241: Table 5.2. Numbers of other species
- Page 242 and 243: Amphibians and Reptiles: Larch Moun
- Page 244 and 245: 228
- Page 246 and 247: 230
- Page 248 and 249: Barrows, C. W. 1980. Feeding ecolog
- Page 250 and 251: Clark, R. J., D. G. Smith, and L. H
- Page 252 and 253: Franklin, A. B., J. A. Blakesley, a
- Page 254 and 255: Harestad, A. S., and F. L. Bunnell.
- Page 256 and 257: Lundquist, R. W. and J. M. Mariani.
- Page 258 and 259: O'Halloran, K. 1989. Spotted owl in
- Page 260 and 261: Solis, D. M. 1980. Habitat use by n
- Page 262 and 263: Young, K. D., A. B. Franklin, and J
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- Page 268 and 269: Table A.1. General approaches for e
- Page 270 and 271: complete count of the territorial b
- Page 272 and 273: Table A.3. Powera for various desig
- Page 274 and 275: Table A.4. Illustration of a Markov
- Page 276 and 277: Obviously, these statements hold on
- Page 280 and 281: Demographic AnalysisAs noted earlie
- Page 282 and 283: the estimate (using the simple equa
- Page 284 and 285: however, we know little about the b
- 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
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- 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
Table A.6. Reliability of trend estimates <strong>for</strong> red-tailed hawks in Wisconsin as afunction of interval Iengtha.NumberPercent of samples Inof Years which <strong>the</strong> error ( JX~ was:In Sample
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