Recovery Plan for the Northern Spotted Owl - DRAFT

3. ConclusionsThis source of bias in x also tends to overestimate X.Sandland and Kirkwood (1981) noted that the recapture probabilities can becorrelated and this leads to biases in the estimate of survival. This effect wastested, but no evidence of this effect was found. This effect is a minor problemwhen recapture probabilities are so high (i.e., 0.80-0.90).Populations of resident, territorial females in all five large study areas havedeclined significantly, at an estimated average rate of 7.5 percent per yearduring the 1985-91 period. The parameter most important in X is the annualsurvival rate of adult females and this parameter has decreased significantlyduring the 1985-91 period. Thus, the rate of population decline has probablyaccelerated.4. Literature CitedBurnham, K.P., and D.R. Anderson. In Press. Data-based selection of anappropriate model: The key to modem data analysis. Transaction of the2001: Wildlife Populations Symposium. l5pp.Hosmer, D.W., and S. Lemeshow, Jr. 1989. Applied logistic regression. JohnWiley and Sons, Inc. New York. 328 pp.Lebreton, J.D., K.P. Burnham, J. Clobert, and D.R. Anderson. In Press.Modeling survival and testing biological hypotheses using marked animals:A unified approach with case studies. Ecological Monograph.Pollock, K.H., J.D. Nichols, C. Brownie, and J.E. Hines. 1990. Statisticalinference for capture-recapture experiments. Wildlife Monograph.107:97 pp.Sandland, R.L., and P. Kirkwood. 1981. Estimation of survival in markedpopulations with possibly dependent sighting probabilities. Biometrika68:531-541.USDI. 1990. Endangered and threatened wildlife and plants; determination ofthreatened status for the northern spotted owl. Federal Register55:26114-26194.328