Recovery Plan for the Northern Spotted Owl - DRAFT

miles from the contiguous population of owls in the province to the north and27 to 31 miles from the other isolated population in Napa and Sonoma Countiesto the east.Owl habitat in the province is found on a greater variety of ownerships than inany other province of the state. Private industrial land ownerships comprisethe largest single group. The multiplicity of ownerships in Marin, Napa, andSonoma Counties, along with early logging history, agricultural, and residentialland developments have resulted in extensive habitat fragmentation. Coordinationand cooperation will be necessary in achieving recovery in this province.Province Isolation. Owl habitat is contiguous along the northern two-thirdsof the 220-mile boundary between the California Coast and California Klamathprovinces. In the southern one-third, suitable habitat in both provinces isnaturally fragmented, and owl sites are at lower densities. The southern end ofthe province is isolated from other provinces, although the range of the Californiaspotted owl extends to within 110 miles to the south (across San Francisco)and 90 miles to the east (across the Sacramento Valley).Predation and Competition. Great horned owls, red-tailed hawks, andravens occur naturally throughout the province. Natural grasslands areinterspersed throughout the province and their occurrence indicates a historyof contact between grassland and forest species. However, current logging isopening second-growth stands, and when forests are limited this harvestdecreases the area available as refuge from avian predators.Barred owls were first identified in the province in 1981. Seven of the nineknown barred owl sites have been found in the last 3 years. Currently, competitionfrom barred owls in the province appears to be low, but barred owlsoccupy at least one site previously occupied by northern spotted owls, and ahybrid is known to have paired with a northern spotted owl (Gould pers.comm.).Vulnerability to Natural Disturbance. Fire probably is the major, shorttermdisturbance event that would affect forests in the province (Appendix F).Much of the coastal area supports moist redwood and Douglas-fir forests thatdo burn. However, fires are generally smaller and less frequent than those inprovinces farther inland. In the mixed Douglas-fir/hardwood/grassland-zoneon the eastern side of the province, fire is a considerably more frequent event.Wind damage, and insect and drought problems also appear to be relativelyminor in the province.Klamath (Callifornia Portion)The California Klamath province is located between the California Coastprovince and the California Cascades province. It is a continuation of theOregon Klamath province south to the Clear Lake Basin in the Inner CoastRange. The area is mountainous and covered primarily with Douglas-firforests. Mixed Douglas-fir forests are common at lower elevations with Douglas-fir/truefir forest at higher elevations. The province primarily consists offour national forests and includes four major wilderness areas. There are a fewparcels of other public lands and some private forestlands. The private andpublic lands mostly occur near the eastern edge of the province.Low Populations. Owl populations are moderate in this province, whichcontains 750 sites. There have been about 455 pairs verified from 1986through 1990. Suitable habitat contains an average density of 3.7 known owlsites per township.60